and Revision History
This section should be very instructive
even if Version 2017, Build 1.4 is the first version you've used.
Version 2017, Build 1.4, was completed
September 3, 2017 and has the following changes relative to Version 2017, Build 1.3
- Changes were made so that the latest-entered solar eclipse data is saved on program
shut-down and used by default after the next boot-up.
- The warning for excessive last-30-days rainfall has been changed. This warning -
the purpose of which is to tip off the user to a likely units-choice error in WXSIMATE
- was previously triggered by 30 inches (762 mm) of rain for imported local data.
However, at least one customer recorded over 30 inches of rain from Hurricane/Tropical
Storm Harvey in the Houston, Texas area, so I have now changed the criterion to 60
inches (1524 mm).
Version 2017, Build 1.3 (August 12, 2017) had
the following changes relative to Version 2017, Build 1.2 (described below):
- In light of my discovery that the GFS model apparently does NOT take eclipses
into account (I cannot see, in a couple of forecasts near the path of totality, dips
in either temperature or downward shortwave radiation flux in the three hourly data
which would suggest that), I have made the WXSIM-Lite mix routine ignore GFS 2-meter
temperature data (via fdata.txt) during the eclipse. There will still be a slight
residual GFS influence, via upper air temperatures, advection, and the return to full
usage of the mix after the eclipse is over, but the temperature dip should be more
realistic, and almost as great as without use of any external data.
- Through investigating acorrec.txt file from an autolearn use, I discovered that the
connection between autolearn.exe and wret.exe, when using the last two years of data
option in autolearn, was failing for sites where commas are used as decimal separators.
The main problem with this was too large of a diurnal range of temperature in the
resulting forecasts. I have now fixed this, but you must simultaneously upgrade to
autolearn.exe 3.6 and wret.exe 2017, Build 1.3, as neither will be compatible with
older versions of the other. Both of these new versions are in the WXSIM 2017,
Build 1.3 upgrade (and demo).
Version 2017, Build 1.2, (July 30, 2017) had
the following changes relative to Version 2017, Build 1.1
The solar eclipse form was changed so that the actual month, day, and year of the
eclipse are entered instead of the previous method of giving the number of days into
the forecast. This way, the form does not need to be updated daily as it was before
for an approaching eclipse.
The eclipse data is now stored in an external file called ecdata.txt, so that if
the program is closed it can still 'remember' the eclipse on boot-up. Also, a third
button for accessing this form was added, to the Auto Run and Other Settings form
(it is also accessible from the Interrupt Planner and from tab 1 under Preferences).
Version 2017, Build 1.1, was completed
May 15, 2017 and has the following changes relative to Version 2017, Build 1.0
Data types were added in the
cty.fdt file to enable more versatility with wind speed forecasts for wind turbines
(typically between 40 and 80 meters above the surface). The wind behavior can
now be made even more site-specific than before (allowing for a range of surface
roughness and inversion-proneness) and also can now supply winds at two heights
(one half that of the other, customized one). Note that this feature is available
only if it was included in the customization.
wret.exe can now handle a change
in file names in CumulusMX, where (at elast under Spanish settings) a period
now appears after the month abbreviation. WXSIMATE and WXSIM-Lite also had changes
allowing for this. In each case the name change is auto-detected, so no user
action is required.
ADDITIONAL NOTE: Occasionally users
may encounter Permission Denied (VB error number 70) errors, which shut down
the program. I declined to attempt anticipating all such errors in my error
trapping code, out of concern about interfering with other error trapping routines.
The cause is usually very simple: a WXSIM file is being used by another process,
which CAN be another program in the suite (i.e. WXSIMATE), if that programs
gets stalled somehow or is scheduled to run overlapping with WXSIM. Another
cause of the problem could be if the user has opened a file such as latest.csv
or latestturbine.csv for viewing in Excel, and left that open. Being alert to
these possibilities will likely prevent the error from ever appearing, or at
least make it fairly easy to fix if it ever does.
Version 2017 (Build 1.0, February
18, 2017) had the following changes relative to Version 2016, Build 1.2 (described
- Added the ability to customize
shadowing by mountains, and effects of sloped terrain in general (on solar radiation)
- Fixed a bug which on rare occasions
caused the date to revert to the start date during the forecast (I think only
one user ever reported this, but I was able to reproduce and fix the problem)
- Added an option (under Start/Auto
run and Other Settings) to omit humidity (dew point) bias and WXSIM-Lite corrections,
which keeping all the temeprature stuff. This was mainly motivated by one user
whose station's hygrometer totally failed, but I've seen other questionable
humidity data in users' files before, so this may have some wider application.
- Created WRETMATE, a companion
program (openable either alone or via buttons in wret.exe, autolearn.exe, or
wxsimlite.exe) which allows you to easily manage the large number of old forecast
(.wxf) files which can acculate over time and potentially make WXSIM-Lite or
WRET/Autolearn rather slow in completing their analyses for bias corrections
("learning"). This new program allows you to (reversibly quarantine
archived forecasts that are too old or have non-standard names. It also lets
you randomly cull the list of forecasts down by a percentage of your choice
(i.e. if you were making forecasts every hour, you could trim the analysis set
down to, say, an average of 5 per day, for quicker processing).
(Note: Version 2016, Build 1.3 was experimental and not officially distributed).
Version 2016 (Build 1.2, June 15,
2016) had the following changes relative to Version 2016, Build 1.1 (described
- A new bug (a division by zero
error) had resulted from fix #3 in Build 1.1 (below), for users having selected
the (mostly used in Canada) humidex option. This has now been fixed.
- Protection was added against older
version's customized files producing an invalid property value error in the
GFS upper air temperature bias settng when used with the new version. I had
not actually had reports of this, but ran across it while experimenting with
older files to find the problem in #1.
Version 2016 (Build 1.0, June 14,
2016) had the following changes relative to Version 2016, Build 1.0 (described
- In WXSIM, there were sporadic
reports of "No READY or GFS data found". In some cases, at least,
this was actually not "true"; data WERE found, but were judged to
be "unbelievable". Specifically, every now and then GFS reports
a relative humidity lower than 1%. I did have a filter to reject anything
that low or lower, but have now eased up on the restriction, so WXSIM will
"believe" values as low as 0.01%. These very low RH's seem to happen
only in upper levels of the atmosphere, so they really won't hurt the surface
- In wret.exe, a couple of people
recently reported an error #9 (subscript out of range). I found this to be
because these users had 10,000 or more forecasts archived! I had not considered
that large of a number when dimensioning arrays (up to 9999), but in fact
people running close to 20 forecasts a day for a year and half can indeed
collect that many! That's frankly too many for wret.exe/autolearn to use anyway,
so the oldest forecasts (.wxf) should be placed in another folder for safekeeping.
However, I don't want users to ever have to see the error, so I've "pre-empted"
it, by checking the numebr of forecasts before the error gets a chance to
occur. Now a message box appears, instructing the user to get the number down
under 10,000 by moving the older forecasts to another folder.
- Protections were added in the
functions calculating dew point from vapor pressure, and dew point from temperature
and relative humidity, in order to handle entered or imported relative humidity
values of zero.
Version 2016 (Build 1.0, March 29,
2016) had the following changes relative to Version 2015, Build 2.1 (described
- A bug, which reversed the sign
of 'residual' corrections to minimum temperatures when using WXSIM-Lite, was
corrected. The errors were usually only a few tenths of a degree, but in rare
cases could be large enough to make the 'minimum' higher than the lowest output
- Modifications were made to the
way WXSIM uses learned bias corrections from cor.txt (i.e. created via autolearn.exe)
along with WXSIM-Lite data, so that out-of-range values are not only limited,
but the values to be written into .wxf files are made so that they would not
have led to limit exceedence in the first place.
- WXSIM now modifies ingested WXSIM-Lite
data by taking the values from fdata.txt and applying a climatological filter,
to weakly trend GFS-derived temperatures and dew points toward seasonal normals.
- Changes were made in wret.exe
to modify values from previously used correction factors if these were determined
using earlier versions of WXSIM. This is because a study of about 20 sites'
correction factors with and without autolearn showed biases due to items 1
through 3, above.
- wret.exe was changed to allow
incorporation of learned bias corrections from the same season as present,
from one and two years ago, as analyzed by autolearn using correc.txt. These
data are also adjusted if they come from periods when an earlier version of
WXSIM was used with WXSIM-Lite (i.e. before this current release date, or
more specifically February 20, 2016, when the first beta version was released).
- The checks for lines of bad GFS
data, for both home site and advection, were made much more robust to shield
against implausible (and often error-producing) values being imported into
WXSIM. These bad values have been very rare - usually only one error in 81
lines of data if they happen at all - and are almost never on consecutive
lines, so the algorithms here replace bad values with ones interpolated from
before and after the line with errors. One error in a line is deemed reason
enough to replace ther whole line.
- An error message in wret.exe,
which could result from a corrupt .wxf file, was enhanced with instructions
about how to correct the problem.
- An option (during customization,
so this will not affect existing jobs, unless I custom add the feature to
your cty.fdt file) has been added to model the effect of sloped terrain, so
that solar energy absorbed by the surface takes this into account. Along with
this, shading from mountains (usually just after sunrise or before sunset)
is enabled, with two "mountains" (and "eastern" one and
a "western" one) specifiable. WXSIM tracks solar altitude and azimuth,
and can now "eclipse" the sun at the appropriate times.
- More information was added to
a number of error and irregularity messages (especially the ones reported
by wxerr.exe after a WXSIM run completes), in order to help the user diagnose
- Information was added to the prompt
which appears when the DST (Daylight Saving Time) box is changed. This prompt
offers the opportunity to make the similar settings in wret.exe and wxsimate.exe
the same as in wxsim.exe. However, this change takes effect only if those
programs are closed, as the prompt now indicates. (This setting can be changed
independently in all three programs anyway).
Version 2015 (Build 2.1, completed
November 3, 2015) has the following changes relative to Version 2015, Build
2.0 (described below):
- Options for customization were
added to enable automatic elevation-based adjustment for the 'home' METAR
and (separately) SYNOP sites' imported temperature and dew point values. This
does not affect customers who ordered before October 24, 2015 and will not
often be used in customizations. The purpose of these additions is to enabled
users in mountainous areas, *without* home weather stations, to get useful
initial surface conditions from METAR or SYNOP import.
Version 2015 (Build 2.0, completed
August 8, 2015) had the following changes relative to Version 2015, Build 1.3
- A safeguard was added (actually,
it had been accidentally disabled in some earlier version) to avoid forecast
errors which could result from use of a too-small set of historical data when
using the learning routine (in autolearn or wret) in conjunction with WXSIM-Lite.
- The enhanced nocturnal decoupling
routine (mainly useful for medium-large islands, such as New Zealand) has
been modified, making it slightly stronger (hence colder nighttime lows in
clear, calm conditions) but also phasing it in and out with the seasons, as
it is needed primarily in winter.
- A warning message was added, if
WXSIM imports local station data showing more than 30 inches (762 mm) of precipitation
in the last 30 days, which is a likely consequence of choosing inches as the
units in Weather Display or Cumuls log files, when in fact they are being
recorded in millimeters, in WXSIMATE.
- wret.exe can now function with
autolearn via WXSIMPRO (theoptional multi-sitecontroller program), so that
separate learned bias correction factors can beautomatically determined for
Version 2015 (Build 1.3, March 10,
2015) had the following changes relative to Version 2015, Build 1.2 (described
- Air density at turbine height
was added as a variable to latestturbine.csv (a file produced only for sites
customized for wind turbine predictions).
Version 2015 (Build 1.2, March 10,
2015) had the following changes relative to Version 2015, Build 1.1 (described
- Better error trapping was added
to prevent users from attempting forecast runs using WXSIM-Lite data, if WXSIM-Lite
has not yet been used to produce a forecast.
- A very rare error, which could
produce an 'Invalid property value' error at the very end of a forecast run,
has been addressed and probably corrected (according to initial tests from
the users reporting the error). This resulted from occasional spurious attempts
to open the advection form at or near the end of a forecast run. While the
exact cause of this has not been identified, the protection consists of having
the form unload itself if activated after 98% of the forecast run is complete.
A log file called adv_activate_error_log is now created to document occasions
on which this protection is called upon, even when the error is successfully
- The default bias corrections to
GFS data on the 4th tab under Preferences/Settings have been changed to neutral
values, presuming that the new 0.25 degree GFS data has no known temperature,
cloudiness, or precipitation biases.
- The data retrieval program, wret.exe,
now has a more informative message when it traps errors due to misplaced data
in log files (such as from Weather Display).
Version 2015 (Build 1.1, January
2, 2015) had the following changes relative to Version 2015, Build 1.0 (described
- Better error trapping was added
to prevent users from attempting forecast runs using WXSIM-Lite data, if WXSIM-Lite
has not yet been used to produce a forecast.
- A very rare error, which could
produce an 'Invalid property value' error at the very end of a forecast run,
has been addressed and probably corrected (according to initial tests from
the user reporting the error)
Version 2015 (Build 1.0, December
31, 2014) had the following changes relative to version 12.12.1 (described below):
- First, a new naming convention
has been adopted, using build numbers and major release years, starting with
2015 being released just prior to that year.
- Most importantly, WXSIM has been
modified to use data from the new companion program, WXSIM-Lite. That program
(included in the WXSIM installation and upgrade packages) makes forecasts
using a different approach, in which GFS (and later perhaps additional model
data) is downloaded, adjusted and interpolated in various ways, and then saved
for later comparison to actual data from a personal weather station. WXSIM-Lite
can then analyze the results to build a sophisticated set of bias corrections
to apply to future forecasts, somewhat like WXSIM's own 'learning' routine.
Months of testing have shown WXSIM-Lite's temperature forecasts to be generally
more accurate - by about 15 percent, and maybe more for some sites - than
WXSIM's own forecasts. However, data also suggest that WXSIM's forecasts have
indepent value, especially for short term and nighttime forecasts, so the
potential exists for mixing of WXSIM and WXSIM-Lite forecasts to produce forecasts
better than either alone (though only a bit better than WXSIM-Lite's forecasts).
This new version of WXSIM allows WXSIM-Lite's temperature and dew point forecasts
to influence WXSIM's output to a user-specificied extent. This is almost sure
to produce the biggest single improvement in WXSIM's accuracy in many years.
It is possible (and advantantageous) to use WXSIM's own learning feature concurrently
with incorporation of WXSIM'Lite's data. Information is stored in WXSIM's
forecasts to indicate the extent to which WXSIM-Lite's data was mixed in,
and this information is carefully taken into account in later use of learned
bias corrections. In other words, both programs can 'learn' at the same time
without conflict or any need of second-guessing on the part of the user.
- IMPORTANT NOTES: The ability to
mix in WXSIM-Lite data is available in WXSIM's professional mode only. Also,
the current plan is for WXSIM-Lite's special data to become subscription only
(at a very low rate, but enough to cover server and ongoing development costs)
at a later date, perhaps in late February, 2015. Meanwhile, the data are temporarily
free of charge.
- The Auto Run form under the Start
menu item has been expanded and organized (and renamed as 'Auto Run and Other
Settings'), and now includes access to the form for mixing in WXSIM-Lite data
and also control over end-of-forecast settings formerly accessible only (and
perhaps inconveniently) on the Output form.
- A new option to alter the appearance
of WXSIM's main programs has been added (button on the new 'Auto Run and Other
Settings' form). This allows use of 'XP and later Windows Styles', if you
are using Windows 7 or later (it actually causes some bad display of option
buttons in XP itself). You can toggle back and forth between the style options
to see what you like best.
- Various cosmetic and informational
changes were made, including a new color scheme for WXSIM's Data Entry form.
- Potential use of imported GFS
data has been expanded to include up to 9 days of data (the maximum length
of a WXSIM forecast), instead of the previous 7.5 day maximum. This will become
relevant when the GFS data downloaded by WXSIMATE is changed over to the upcoming
0.25 degree resolution version. The implementation date of this is uncertain
as of this writing, but hopefully will be done by sometime in February, 2015.
- Wording of the convective bulletins
about 'Showers unlikely' and 'Showers very unlikely' has been changed by adding
the word 'Convective', so that contradictory-looking text about showers being
unlikely while (stable) rain is forecast will no longer appear.
- The autolearn.exe program has
been updated to version 2.0, which allows graphs of the history from correc.txt
- The Daylight Saving Time setting
(always a pain in the past, I know) is a bit simpler now. When you change
the check box in WXSIM, it should make the same change in wret.exe and wxsimate.exe
as well (that does not work in reverse, though). I do have a "warning"
system in place, which looks for evidence that the setting does not go with
the computer's clock. It's still a bit complicated, though, because there
are reasons (at least for me) to alter the setting (for example, in wret.exe,
if I'm analyzing old forecasts from another season). So, the change is not
made automatically. However, it should warn you (at least the first time DST
status changes) and you can now make the change globally.
- A small bug was fixed: at the
beginning of the forecast, the advection routine was displaying (though apparently
not actually using) a "normal" temperature (for the time and date),
instead of the actual temperature, as the "home" temperature, against
which actual upwind temperatures are compared to generate an advection profile.
This has been corrected so that the actual temperature at the time is displayed.
Version 12.12.1 (May 3, 2014) had
the following changes relative to Version 12.12 (described below):
- The ability to forecast wind speeds
at specified heights above the ground, for use in forecasting wind turbine
power output, was added. This additional data is displayed, along with other
relevant data, in a new output file called latestturbine.csv. This feature
is not generally available to all users, but is something I can customize
specifically for the site, based on turbine height, surface roughness, and
(optionally) past wind history.
- Warnings and measures have been
added to wret.exe to prevent users from trying to use 'combined' data in the
analysis for learned bias corrections. The purpose of the 'Combine' box on
the comparison to actuals graph is to allow display of hourly-averaged data,
not to develop correction factors.
- A bug in wret.exe, which could
cause an 'Invalid procedure call' error, has been corrected.
- Another bug in wret.exe, which
occasionally and mistakenly caused rejection of data (for developing learned
bias corrections) has been corrected. This was a simply typographical error
in a variable name in my code.
- wret.exe now is able to circumvent
a problem involving reading of WeatherLink data. It seems that occasionally,
the first couple days of the month (for one user, anyway) have some garbled
data, either due to the .wlk files themselves, or perhaps to WXSIMATE's interpretation
of that data (which is binary "gobble-dee-gook"). It now skips over
such stuff until it find reliable data and uses only that. This affects the
autolearn and Auto Select routines, but again, only if you are using WeatherLink.
- wxsim.exe has a change which should
have no effect whatsoever on any existing customization. This is a customizable
feature controlling the extent of mixing in light winds under strong inversions,
primarily in arctic regions. Generally, the problem (based on data from a
site in Yukon, Canada) was that such mixing was too weak, and this change
makes it possible for me to strengthn it, if needed, in customizing.
- An erroneous message telling the
user to uncheck the 'Run optional DOS batch file' (when it was in fact not
checked) in WXSIM has been corrected. Actually, I am not sure if this bug
was present in the official version 12.12, or if it was only in a beta version
since then. Either way, it is now corrected.
- A rarely occurring, but longstanding
(several years!) error #6 ('overflow') in both wxsim.exe and wret.exe has
been solved. This error occurred when the 'Shell' command was called to open
another program (such as wxsim.exe opening wret.exe at the end of a forecast).
I finally discovered that it was a case of my having declared the 'task number'
to be an integer, but occasionally, on some computers, the system would assign
a number bigger than 32767, which is the highest integer allowed. I have now
declared this variable as 'double precision', which should totally sove this
Version 12.12 (February 5, 2014)
hadthe following changes relative to Version 12.11 (described below):
- A more sophisticated treatment
of the learned bias corrections has been implemented. This modifies the "slope
bias correction" in such a way that there is a smooth tail-off in the
effect when departures from normal temperature are greater than the average
amount of departure from normal in the analysis. Something like this existed
in previous version, but the function was discontinuous in slope and did not
reduce the bias sufficiently. This one reduces it to about a third of the
"learned" value when departures are more than about twice the average
amount of departure. Also, a very thorough statistical analysis of thousands
of forecasts, combined with studies using randomly generated data in Excel,
suggested that extending small sample sizes of data to a larger range of conditions
presents a problem: part of the error in error versus forecast departure from
normal is an artifact of using (necessarily) the forecast departure as a basis,
instead of the actual departure as a basis. Essentially, a too-warm forecast
also tends to be an "above normal" forecast. I have now standardized
the slope to be defined as appropriate when standard deviation of departure
from normal is twice the standard deviation of the error itself. Outside this
range, the slope is altered towards being a bit more "extreme" (allowing
greater departures from normal). I believe this change will allow better transition
between seasons, for instance by anticipating the possibility of larger temperature
excursions in the fall, after a monotonous summer.
- Changes were made in wret.exe
to the plots of error versus date and versus departure from normal, to increase
readability and reflect the changes listed in (1), above.
- Bitmap plots, named errdate.bmp
and errdep.bmp, are now made when the plots mentioned in (2) above are viewed,
or when autolearn.exe completes its run of wret.exe.
- The default "distance ratio"
on the advection form was reduced from 1.15 to 1.1, as this now appears to
make more accurate fits for upwind advection profiles.
- An occasional overflow error (Visual
Basic error number 6) resulting from the use of the Cint function in Visual
Basic, with values over 32,767, was corrected by using Int(x+.5) instead.
This error may have existed for a long time, but the change in the distance
ration from 1.15 to 1.1 may have made it more likely to show up.
- A routine intended to better model
mixing out of morning temperature inversions was found to have bad effects
(a brief dip in temperature around noon) on cloudy days with light winds,
mainly in winter at high latitudes. This has been corrected by phasing the
effect out as cloud cover increases.
- Changes were made to hopefully
avert a rare printer error in cases when no printing was requested.
- Changes were made to slightly
reduce the diurnal temperature range and also the rate of air mass modification
in colder than normal weather. This was based on careful study and re-running
of forecasts of historical data, mainly during arctic air outbreaks.
- A sort of climatological filtering
has been applied when GFS model data is being used, so that temperatures past
about 2 days into the forecast are trended slightly towards normal. This "correction"
is actually only about half the theoretically optimum value, so as to preserve
some of the underlying run-to-run variability, but still tone down unrealistic
extremes which crop up at times. The treatment is season and location specific,
by taking into consideration typical standard deviation of error in GFS data
along with typical standard deviation of actual temperature.
- Maximum daily snow depth was added
(to the existing average daily snow depth) in the Supplemental Dat section
in the scrolling text output and in latest.txt.
- Internal changes were made in
the main forecast module to allow room for the additional code.
- The learned bias corrections displayed
under Preferences/Settings in WXSIM are now in familiar units (i.e. degrees
F or C) instead of the cryptic raw values diplsayed in previous versions.
- A failure to clear out old data
had sometimes caused brief (only in the first three hours or less of the forecast)
excursions, mainly in barometric pressure, when using GFS data. This has been
- A very slight increase in the
weighting of the "clear thickness maxiumum" (an estimate of clear
sky maximum temperature based on the thickness of the lowest 130 millibars
or so of the atmosphere) was made, so that daily maximum temperatures will
be constrained slightly (a couple of tenths of a degree, typically) closer
to this figure.
Version 12.11 (January 1, 2014) had
the following changes relative to Version 12.10.2 (described below):
- An oversight in wret.exe caused
(only for users of Cumulus) the Comparison to Actuals, as well
as the learning routines (through Auto Select or autolearn.exe) to jump back
to January, 2013 after December 31, 2013, instead of proceeding to January,
2014. This has been corrected. Since the change involves only wret.exe and
the official release was just yesterday, I am simply repackaging the installer
with this change, rather than renaming the entire version.
- Options for sea surface temperature
on the Diurnal Breeze form were made more simple and explicit. There are now
option buttons for either using default sea temperatures or user-entered ones.
These settings take effect as soon as the OK button is pressed, and are saved
for future runs until changed.
- The default (climatological) sea
temperature now changes with each day of the forecast, rather than retaining
the value from the first day.
- A typographical error in a warning
about far-from-normal sea surface temperatures was corrected: "10.8"
Celsius was changed to "6" Celsius.
- Messages about missing local calibration
data (from localcal.txt) are now deferred to the auxiliary external messaging
program (wxerr.exe) so that they will not interrupt auto runs.
- The 'Offset' and 'Range' factors
in WXSIM were previously simply stored values which the user needed to keep
consistent with 'Dep' and 'Rng' in wret.exe (which are used in developing
learned bias correction factors through Auto Select or autolearn.exe). They
were not - and still are not - used in any way in generating a forecast, but
are written into latest.wxf as a record of the user's intent in wret.exe at
the time of the forecast. Changes have been made so that the values shown
are read, both at forecast time and when the form is opened, from wret.exe's
initialization file, retini.txt. Also, the boxes displaying the two values
in WXSIM are now disabled for user modification, since they need to be enetered
in wret.exe to be used.
- An unused form (gfsadj, whose
functions were incorporated into the tabbed form under Preferences/Settings
several versions ago) was deleted to reduce program size.
- Error trapping was improved in
wret.exe to avoid crashes when latest.wxf is not found.
- Changes were made in the auto
select ("learning") routine of wret.exe to avoid a "file already
open" error that was reported by two users.
- Error trapping was improved in
wret.exe's comparison to actuals and learning routines, by displaying the
last line read from a potentially faulty weather station software log file
in the error message. This allows the user to quickly find and correct the
problem in the log file. The example motivating this change was a case of
a few dates being out of order in a Weather Display log file, which caused
a 'Subscript out of range' error in wret.exe.
- Minor cosmetic changes were made
- Appropriate changes were made
to WXSIM's blue-text help file.
- A bug which allowed the year to
remain the same in .csv files, when January 1 is reached, was fixed. The change
also applies to other routines which are functions of the year, such as climate
and solar forcings.
- A bug similar to that above, involving
the UTC time stamp in the lastret.txt file, was fixed in wret.exe. This also
now has correct output across the change to the new year.
- In wret.exe, bitmap graphics
are now automatically produced for the error as function of date and of departure
from normal graphs when these are displayed. Also, these are briefly displayed,
closed, and graphics created auto,atically by autolearn.exe when that program
- Small wording changes were made
in the output of wret.exe's auto select learning routine.
- Small changes were made in the
advection form's output for quality of the curvature fit. Previously, erroneous
values for "Spd" and "%" were briefly shown (but not actually
used in the final fit). Also, the advection site map now shows the number
of sites actually used for the fit rather than the total number found.
- On the data import form, the number
of sites found for advection was sometimes shown too large by one (when MOS
runs out and the program defaults to GFS). This has been corrected.
- A warning message now appears
in WXSIM if the status of the DST (Daylight Saving Time) box does not match
the status derived from internal data for the computer (derived from a comparison
of the GMT system time and the adjusted time on the computer's clock, considering
WXSIM's time zone information for the site). This message occurs only at start-up
of WXSIM (as an internal message box) or in auto run at the end of a forecast
(as an external message box which does not interfere with the forecast). There
may be some users who run forecasts for sites outside of the computer's time
zone. To accommodate this, there is an option to prevent the message from
appearing after the first time.
- A possible fix to a problem involving
a rare problem of failing to get fresh GFS data on the first run of the day
has been implemented. Actually, the code for this fix existed in the last
two versions, but was probably ineffective because a variable had not been
declared globally; now it has.
- Small cosmetic changes were made
to a couple of forms.
Version 12.10.2, (September 23, 2013)
had the following changes relative to Version 12.10.1 (described below):
- One or more causes of an occasional
error 52 (bad file name or number) were corrected. As of this writing, such
an error is being reported by only one user, with the cause seemingly something
very system-dependent. If such an error is still encountered, two possible
workarounds are UNchecking 'Minimize forms', CHECKING 'Omit log files' (both
these on the Auto Run form), or (an almost certain fix) having WXSIM close
after auto runs, and be reopened by a third-party scheduler.
- Wording was improved to be more
instructive in the case of messages about not not having imported model data.
- A bug which often caused failure
to use local station data in the calibration run was corrected. A separate,
but related error was fixed in WXSIMATE as of version 5.3.2, completely correcting
this type of error (which had only very minor effects on most forecasts).
- Autolearn.exe has been updated
(now version 1.2) to improve clarity of use and avoid common user mistakes
in connection with wret.exe, which also had small improvements in wording.
- wret.exe now formats correc.txt
properly even with regional and language settings using commas as decimal
separators (previously older data was split awkwardly into multiple lines).
Version 12.10.1 (August 16, 2013)
had the following changes relative to Version 12.10 (described below):
- A new program called AutoLearn
has been added to the WXSIM suite. It allows scheduling of automated "learning"
runs (for use in WXSIM's Professional Mode) by wret.exe, and changes were
made in wret.exe to accommodate this. AutoLearn is actually a separate program,
with a registration fee for full-featured use. In demo mode, it has a fixed
10 day analysis period, which is too short for optimal results, but can still
give users a good look at how it works. Note that this is for convenience
only, as manual use of the AutoSelect feature in wret.exe accomplishes the
- WXSIM's response to the learned
bias correction factors has been fine-tuned. Testing revealed that, under
normal use (including GFS and FOUS data and advection), the overall temperature
correction and the "slope" parameter supplied only just over half
the needed correction on the first try, so that a period of time two or three
times the analysis period (which is often months) would be needed for essentially
full response, by which time short-term and even seasonal effects would be
largely blurred out. The range and dew point factors were fairly well-tuned
already, but all four parameters have now been carefully adjusted to yield
full response on the first use, with or without GFS, FOUS, or advection data.
- The range of allowed values in
the 'slope' correction factor (which influences the 'pull' towards climatological
normal temperatures) has been expanded to +/- 40% (instead of the previous
25%), in light of data which showed these more extrme settings are sometimes
needed. However, this usually occurs in rather monotonous weather with few
air mass changes, and extrapolation to more extreme temperature events may
not be warranted. For this reason, the slope factor now contains information
about the range of departures from normal in the anaylsis, and WXSIM uses
this to reduce the effect to no more than +/-20% for temperatures well outside
this range, smoothly transitioning to this figure with increasing departure
- Minor informational and cosmetic
changes were made in both WXSIM and wret.exe. These include parenthetical
information in WXSIM's File menu that retrieving data means opening wret.exe,
and that the Cull/Append routine is seldom used. In wret.exe, departure from
normal is now shown to be an 80%/20% mix of forecast and actual values (in
that order, and as they have been for some time) and instead of average forecast
and actual departure from normal, the mean values for the cooler and warmer
halves of this 80:20 mix are shown.
- Clicking the 'Cumulus' option
on the Comparison to Actuals form now enables entry of text, regardless of
prior choice (previously, it was necessary to have checked Weather Display
first - an oversight in the implementation of Cumulus use for this.
- It was found that, under certain
scheduling conditions, auto run could generate messages that the data were
over 24 hours old, on the first run of the day. This also significantly impacted
the accuracy of those forecasts. Changes have now been made so that this error
should no longer occur (though the message should still appear if the data
actually ARE over 24 hours old).
- I discovered (in studying Finnish
users' data) an odd shape to the diurnal temperature curve in the May-July
period. The temperature would rise quickly in the morning, then warm almost
linearly until a somewhat too-late high temperature (about an hour or two
later than reality). I traced this to an oversight in a very old routine which
estimates the times of day when the temperature should be near the daily mean,
as these figures help inform the onset of mixing with daytime heating. I apparently
had not tested this at these latitudes near the solstice, so the problem has
been there a long time! This has now been fixed. The change to wxsim.exe is
significant if you live more than 45 degrees from the equator and are having
daylight exceeding 15 hours, the difference being very minor until you reach
about 60 degrees latitude, but very important near and north of the arctic
- There is now a trap set for errors
at the end of an auto run run, at the point where WXSIM attempts to boot wret.exe
to make graphics and the lastret.txt file. Such errors have been elusive as
they seem to be sensitive to other processes on the computer, because rebooting
would sometimes prevent the problems (which tended to be intermittent anyway).
It should catch any error #6 (overflow) errors and just act like nothing happened
(which I think will be OK). It might catch others, too, with a message, and
then hopefully keep going. This error may have also led to bad .wxf files
and errors in wret.exe. Incidentally, such errors were the reason for the
'Ext boot' option (check box near the 'Graphic' check box on the Output form).
This option remains, just in case it's still ever needed.
- A change was made which should
prevent a certain 'file already open' error.
- The document 'Evaluating Temperature
Forecast Accuracy in WXSIM'(written on July 6, so that some of the screen
shots are very slightly outdated) was made part of the standard WXSIM distribution
Version 12.10 (June 30, 2013) had
the following changes relative to Version 12.9 (described below):
- The sea breeze routine's warning
system for abnormal sea surface temperatures has been changed so that only
discrepancies larger than 6 Celsius degrees (10.8 Fahrensheit degrees) will
trigger a message that actually interrupts program execution. Discrepanices
greater than 3 Celsius degrees (5.4 Fahrenheit degrees), but no more than
6 C will now trigger only an external message which does not interrupt the
program. Discrepancies larger than 1.5 degrees will be recorded in the file
- Sea level equivalent water temperature,
and also normal default values for water temperature and its sea level equivalent
are now displayed on the diurnal breeze form.
- Small informational and cosmetic
changes were made to the Save Data form.
- Internal changes were made regarding
the reading of registration codes.
- A bug in the soil data routine,
which sometimes caused it to fail to read station data (especially when less
than four depths are used and blanks instead of "999" were entered
in WXSIMATE) was corrected. Slight changes in the extrapolation of moisture
to non-measured depths were made also.
- A message was added to WXSIM's
Soil Data Entry form to prevent users from checking more than 5 agricultural
output variables (though all variables are saved for later viewing in wret.exe).
- Changes were made to the way in
which layer relative humidities from NAM FOUS data (North American users only)
are interpreted as cloud cover. In particular, extensive research showed that,
with steep lapse rates (such as in summer), higher relative humidities are
needed to produce overcast conditions (perhaps because areas of downdrafts
produce clearer patches) in levels 2 and 3. The main effect of this change
is that some overcast or mostly cloudy summer forecasts will now be mostly
or partly cloudy instead.
- It was found that - when FOUS
and READY or GFS data were used together - the averaging was (inappropriately)
somewhat dependent on the time interval (a function of the output interval
and the number if iterations per interval). Changes were made in the way FOUS
influences cloud cover and precipitation, so that these discrepancies are
reduced to a trivial level, especially if the time interval is kept to 10
minutes or (preferably) less. This occurs, for example, with an output interval
of 30 minutes and 3 iterations per interval (while 6 would be better, for
a 5 minute interval).
- An internal typographical error
in WXSIM, which could have (but probably never did) affected sunset times
in unusual circumstances, was corrected.
- Comparison to actuals is now avaiable
in wret.exe for Cumulus. This also makes it possible to use (in professional
mode) the "learning" routine with Cumulus.
- Informational changes (an extra
decimal place, number of forecasts analyzed, time to complete the run, etc.)
were made to the Auto Select results in wret.exe.
- Major improvements were made
to wret.exe's Comparison to Actuals and Auto Select routines. A wealth of
statistical data is (optionally) displayed, both graphically and as text on
the comparison graphs. These include not only net and mean absolute errors,
but root-mean-square errors and standard deviation of error, as averages over
periods ranging from a day to 30 minutes.
- More information was added to
the Auto Select output in wret.exe, such as indicators of four different types
of reasons for data rejection, and user input regarding criteria for rejection.
Also, message boxes have been added for guidance in the use of this routine.
- A UTC date/time stamp was added
to the end of each line of data in lastret.txt (produced by wret.exe), mainly
to help developers of php scripts for displaying WXSIM forecast data graphically.
- Minor formatting changes were
made to lastret.txt's output, including a one decimal place (instead of a
whole number) for sea level pressure in millibars (hectopascals) and an extra
space in front of lifting condensation level if its value reaches or exceeds
10,000 (this should happen only if using feet as units).
- Error handling has been improved
in wret.exe, so that when it encounters a corrupt forecast file (caused by
improper closure of WXSIM - by the user, due to an error, or due to a power
outage), it advises the user of the reason for the error and gives instructions
for how to remedy it (previously it just gave an error message and crashed
- Very minor cosmetic and informational
changes (i.e. punctuation and spelling) were made to both wret.exe and wxsim.exe.
Version 12.9 (March 4, 2013) had
the following changes relative to Version 12.8.11 (described below):
- A protection has been added to
handle the possibility of the site specified in custinit.txt not having corresponding
METAR code and name with any site in cty.fdt. Previously, error messages such
as "Dew point cannot exceed temperature" may have appeared in such
cases (which would be extremely rare, indicating probably file corruption).
- The messages "Dew point cannot
exceed temperature" and "Unrealistic barometric pressure" are
now skipped in auto run mode, while the dew point is quietly set to the temperature
and the barometric pressure to the world-wide sea level mean. These changes
also occur even if the messages do appear (in manual mode).
- The routine for writing the latest.csv
file was inappropriately combining weather types 1 and 2 and writing this
as type 1 (while correctly writing type 2). This has been corrected.
- A check on program startup (upon
loading site data) has been added to see if the computer uses commas as a
decimal separator. If so, the setting 'Use semicolons for .csv files' defaults
to true (checked, on the Auto Run form) in order to avoid errors in the writing
of the .csv files.
- The function for calculating distance
to the sun was fine-tuned, yielding a slightly smaller difference between
perihelion and aphelion and a shift of a bit less than a day. The maximum
effect on solar radiation is at the surface is no more than as 3 watts per
square meter, and resulting temperature effects in the program are on the
order of a tenth of a degree. The main reason for the change was to make solar
radiation outputs as accurate as possible. Also, I did a fresh study of the
solar radiation model, and found that the only changes appropriate were the
- A carefully devised function for
the 11 year solar irradiance cycle was constructed, including an assumption
that over the next cycle or two, the sun may enter a relatively quiet phase,
perhaps approaching that of the Dalton minimum in the early 1800's. The peak-to-valley
variation of about 1 watt per square meter is assumed to decrease to about
0.7 w/m^2, with a drop in the average by about 1 W/m^2. I assumed (with little
basis, other than comparison to the Dalton and Maunder minima) that this dip
may last about 50 years. Actually, direct effects of this on temperature are
trivial (on the order of a tenth of a degree) compared to other sources of
error. I mainly included it in case it is of further interest later.
- The "use global warming"
option has been updated, based on a recent (last 12 years or more) leveling-off
of the previously rising global mean temperature. This "flat" stretch
is documented in both the NASA GISTEMP and Hadley Center HADCRUT data. It
may be partially explained by recent small decreases in solar activity, both
as part of the normal cycle and changes in the cycle itself. To incorporate
this, I applied the solar cycle model described in (6), and also applied a
gentle concave up curvature whereas earlier I had it linear. It still produces
about 3 Celsius degrees of warming between 1965 and 2100, but with only a
slight rise before 2020.
- This is really an addition to
WXSIMATE, not WXSIM per se, but is relevant enough to mention here: WXSIMATE
can now read data from the program Cumulus, by Sandaysoft, in addition to
the previous set of software packages with which it is compatible: Davis WeatherLink,
Brian Hamilton's Weather Display, Ambient's Virtual Weather Station, and Quimisur
(a Spanish company). At this time, the use of Cumulus is limited in three
ways: (1) the "compare to actuals" tool in wret.exe is not functional
for Cumulus, (2) the associated "learning" routine are not functional
in wret.exe, and (3) soil temperature and moisture data are not read. (2)
and (3) are features of WXSIM's professional mode and therefore do not affect
use in standard mode. So, standard mode is very nearly full-featured for use
with Cumulus. I may add some or all of these features in the future, but do
not have any current goals for when this might get done.
- Reports from high-latitude users
(i.e. Finland) indicated that WXSIM was reducing snow depth too rapidly in
sub-freezing weather. Investigation, backed by research such as in this study:
Differences in Compaction Behavior of Three Climate Classes of Snow (PDF)
showed that the main problem was not melting or sublimation, but overly rapid
compaction of the snow under its own weight. Changes were made to generally
reduce this rate, and also make it temperature dependent (slower compaction
at lower temperatures).
- A change was made which should
fix the occasionally reported 'forgetting' of the 'RAOB' and 'READY or GFS'
check box settings on the data import form (assuming the problem found was
the only cause). When unrecognized and not corrected, this problem led to
messages about no model data being found, and the resulting forecasts were
- A variety of messages which previously
interrupted program execution, awaiting a user response, have now been handed
over to a new, small program (included in the WXSIM upgrade and demonstration
packages) dedicated to their display. This allows WXSIM to continue and complete
the forecast and yet assures that the users knows about the problem(s), which
are usually about missing data. The messages are also displayed in a text
file called msglog.txt.
- A program called trimlog.exe has
been included in the package (but not given a Desktop icon at this point).
This is a tool for users of the Weather Display program who may find import
into WXSIMATE to be slow. Trimlog can run on its own scheduler to produce
much smaller versions of the Weather Display log files, allowing import time
to be cut by a factor of almost 10.
Version 12.8.11 (July 16, 2012) had
the following changes relative to Version 12.8.10 (described below):
- The 'suspicious initial wind data'
message in auto run now appears only under more extreme conditions, 32 mile
per hour discrepancy as opposed to 16, though values over 16 are still reduced
to 16 before use.
- A limit was placed on the lapse
rate between levels 3 (approximately 700 mb, for most sites) and 4 (500 mb),
to keep it a bit short of the dry adiabatic lapse rate. The value used is
slightly dependent on surface elevation and is based on considerable research
of historical RAOB soundings. Also, a bug in a beta release of this version
has been corrected in the final one here.
- For sites with actual (not adjusted
to sea level) surface pressures below 970 mb, the Total Totals Index (TT)
has been modified by mixing it with an alternate definition (called HLTT or
High Level Total Totals) in which 700 mb replaced the original 850 mb in the
formula. The K, KO, and Showalter indices are modified similarly but indirectly,
based on the change between TTI and HLTT. This indirect method was used because,
while I did have some data correlating TT, HLTT, and convective threat, I
did not have separate data correlating 700 mb version of the other indices
with such threats. The new indices are equal to the old ones with surface
pressure above 970 mb, and gradually transition to the high level versions
as a surface pressure of 850 mb is reached. This change was made because some
moderate to high elevation sites were getting overly aggressive convective
- The 'reduce superadiabatic' routine
was modified to have less effect for surface pressures below 970 mb (that
is for higher elevation sites). When the previous version was used for these
sites, high temperatures became somewhat too warm and the air too unstable.
The effect now transitions gradually from its original value for surface pressures
above 970 mb, to half that around 945 mb, to very small but non-zero values
at much lower pressures.
- The READY/GFS bias correction
(top of tab 4 under Preferences/Settings) has been modified so that, while
the initial temperature correction is the same as before (with a given setting),
the trend part is reduced to 0.67 of its original value. This was done to
correct a tendency, in long range (over a week) forecasts for too-large of
a drift to occur. For instance, while an input positive value of, say 0.5,
would produce only a modest temperature for the first few days, later in the
forecast the change would become too large. The change shouldproduce more
consistent day-to-day temperatures (aside from a multitude of other effects,
- A bug, which could produce a 'file
already open' error after a message about GFS data being for the wrong site,
has been fixed (the message can still appear, but hopefully not the error
that could follow it).
- Many new avenues of communication
have been opened between WXSIM and the optional multi-site controller program,
WXSIMPRO. One example is a short file called wxsimopen.txt, which should consist
of the number 1 if WXSIM is open, and 0 if it is not. Also, WXSIMPRO can now
optionally have WXSIM default to climatological normal sea surface temperatures
instead of retaining values from an earlier run. Messages related to this
in both programs have had wording changes. Most of these changes are not visible
when not using WXSIMPRO.
- A change was made in the Retirevel
program (wret.exe) to enable the Auto Select routine to successfully bridge
across from one month to another (previously, for VWS data, forecasts spanning
months were rejected from the analysis). Months were already bridged successfully
for Weather Display and WeatherLink data, at least.
Version 12.8.10 (December 19, 2011)
had the following changes relative to Version 12.8.9 (described below):
- A bug, which could occasionally
cause an 'invalid property value' error, has been fixed. This error would
occur if WXSIMATE somehow (perhaps through some kind of interruption) failed
to finish writing the localcal.txt file. It is still possible WXSIMATE may
do this, but there is only a trivial loss of data which would have no perceptible
effect on WXSIM's forecast. Now WXSIM should be able to handle this situation
without error or interruption.
Version 12.8.9 (November 23, 2011)
had the following changes relative to Version 12.8.8 (described below):
- The wret.exe module's 'Auto Select'
routine for determining learned bias correction factors has been improved
in two ways. First, a careful study of the effect of corrections motivated
a change in how the 'tendency towards normal' factor is determined. These
factors should now be slightly more conservative, and accurate, than before.
Second, the heavier weighting of more recent data is now an option (the 'Weight
recent more' box must be checked for this), with the default being to weight
all data equally. The equal weighting is a bit 'safer', but unseasonal spells
may still call for the heavier recent weighting.
- A few places in wret.exe allowed
values to be printed in lastret.txt with enough digits to run columns together
(an earlier attempt to correct this still left loopholes where the figures
100.0 and 10.0 could appear). This has been corrected.
- Minor changes were made to the
help file, such as noting that the NGM model is no longer in production (as
Version 12.8.8 (July 19, 2011, and
August 12 for the wret.exe module), and has the following changes relative to
Version 12.8.7 (described below):
- The default value (and only value
in standard mode) for the minimum level 1-3 sky cover necessary to allow external-model-based
precipitation was changed from the previous 40% to 20%.
- The minimum 12-hour precipitation
probabilities for "possible" and "likely" thunder have
been changed from 15% and 25%, to 10% and 20%, respectively, thus making appearance
of thunder slightly more likely in the plain text output. This would be most
noticeable for precipation probabilities between 10 and 15%, where the former
"Precipitation showery or intermittent" wording will change to "Scattered
- In wret.exe, the number of decimal
places for precipitation rate and total precipitation has been reduced in
the case of large numbers (i.e. 100 mm or more) which would run into other
columns if the original decimal places were retained.
- In wret.exe, horizontal visibility's
units are now dependent on the temperature unit choice instead of the previous
thickness unit choice. When Fahrenheit is in use, visibility units are now
miles; with Celsius, they are in kilometers. Also, if the visibility (in either
unit system) has a value less than 10, one decimal place will be displayed.
(Previously it was a whole number in all cases).
- In wret.exe, you may now check
up to 15 temperature items and 15 'other data' items. As before, only the
first 5 of each will be displayed on the screen, but the entire set will appear
in lastret.txt. Also, some minor formatting changes were made in lastret.txt,
to remove some of the excess spaces when fewer than the maximum number of
items are selected.
- In wret.exe, two new temperature
values were added: the maximum and minimum temperatures from which daily max
and min values are obtained. Around the time of the maximum, the difference
between the new max value and the most likely 1.5 meter temperature (the main
forecast value) is an indication of the amplitude of the largest short-term
fluctuations likely (though the new min value at the time of the max is less
meaningful, and often a bit warmer than the lowest temperature due to short-term
fluctuations). Around the time of the daily minimum, the difference between
the new min value and the 'main' temperature indicates fluctuation amplitude,
with the max value a bit less meaningful. In short, these are simply values
from which daily max and min temperatures can be extracted.
- In both WXSIM and wret.exe, the
upper end of the convective sensitivity adjustment has been extended to +2
instead of the previous +1.
- In both WXSIM and wret.exe, minor
cosmetic changes and changes to the help file were made.
- In both WXSIM and wret.exe, summaries
at the end of the text display now show 24-hour max and min temperatures to
the nearest tenth of a degree, instead of the previous whole degree. This
should not be understood as a claim of higher accuracy, but the decimal places
might be interesting for comparisons or identifying trends in the program's
- In wret.exe, after the message
that too many temperatures (or 'other data') options are checked, the program
will automatixcally uncheck the last item you check, thus preventing errors
that would occur if you proceeded without heeding the message.
- This item was actually present
in 12.8.7, but I forgot to list it below: A check box on the Auto Run form
allows you to have the date listed along with the day of the week in the plain
- Numerous improvements and additions
were made to the agricultural module. Soil moisture is now reported in soil
moisture tension as well as percent by volume, with these being functions
of each other as well as of soil type. Both soil moisture and temperature
can now be imported (via WXSIMATE Version 5.0) from either WeatherLink (for
up to 5 depths) or Weather Display (for one depth, and possibly more in some
later version), and this can work in auto mode as well as manually. Irrigation
can now be planned on the Interrupt Planner, and this, along with soil moisture
tension, can be plotted in wret.exe as well as output in WXSIM itself.
- Several small cosmetic, organizational,
and wording changes were made in wret.exe.
- An occasionally encountered bug
producing a "division by zero " error has been corrected. This problem
most likely occurred only if local calibration data was being used, and required
a rather special set of circumstances, so that it was sporadic in nature.
- In addition to the changes listed
in (12), the algorithm for the default soil moisture (as a function of location,
season, and recent precipitation) has been improved considerably.
- In wret.exe, a bug - which caused
text and lastret.txt display of all soil moistures to be that at depth 1 -
has been corrected.
- Bugs which could cause division
by zero or invalid property value problems were fixed. These were associated
with interpretation of local station calibration data in localcal.txt.
- Output format of certain variables
to lastret.exe in wret.exe, such as severe weather indices, was changed so
that values of -10 or more negative are rounded off to whole numbers, so that
columns of data won't run together.
Version 12.8.7 (June 10, 2011) had
the following change relative to Version 12.8.6 (described below):
- The results of a recent careful
study on thunderstorm activity as a function of various stability parameters
(especially the K and Total Totals indices) using many U.S. surface and upper
air sites' historical data (spanning up to 25 years) - combined with information
from two large studies in Europe (Germany and the Netherlands) was used to
substantially improve WXSIM's convective bulletins. A very thorough description
of this improved algorithm is now included in this manual.
- Slight changes were made in the
wording of convective bulletins. Also, the following plain text convective
output now consists of:
" Precipitation showery or intermittent."
" Scattered showers possible."
" Scattered thundershowers possible."
" Scattered thunderstorms likely."
" Scattered thunderstorms likely, some possibly severe."
" Thunderstorms very likely, some possibly severe."
" Thunderstorms very likely, some severe."
" Severe thunderstorms likely, with possible tornados."
These were removed:
" Thunderstorms likely, some severe."
" High risk of severe thunderstorms and possible tornados."
- The plain text convective bulletins
now take into account thresholds of 12 hour probability of precipitation.
This helps screen out occasional contradictory information (such as thunderstorms
"likely" when rain chances are below 20%), though it may cause some
inconsistency with the scrolling convective bulletins, most likely in that
a few convective bulletins may be more aggressive than the final plain text
output. If this is found to occur frequently, a small downward adjustment
in the convective sensitivity may be in order, since the final plain text
forecast incorporates a bit more information than do the bulletins.
- The automatic level 2 cloud cover
minimum of 60% during precipitation has been reduced to 45%. This could increase
temperatures very slightly on afternoons with light shower activity, but a
recommended slight change in the GFS temperature and cloud cover bias (see
#6, below) may just about exactly cancel this out on average.
- A major review and readjustment
of the routines for finding heights and thicknesses of the various pressure
levels was conducted. The changes made include updating the virtual temperature
calculation to an official published equation (previously it was a fairly
good, empirical one I had developed), including level 3 and 4 relative humidity
values (values up through level 2 were already incorporated, but above that
default values had been used), establishing new ways of averaging the limited
temperature data to best characterize layer average values, and (importantly)
removing an altitude-based correction to the acceleration due to gravity,
so it is now a constant 9.80665 m/s/s, as appears to be standard for the geopotential
(as opposed to geometric) heights that are standard in imported model data.
- A thorough review of GFS temperature
verification results, from this site:
- STATS VSDB
- strongly suggests that a cold
bias which existed a few years ago has been largely corrected. For this reason,
the default value for the upper level temperature bias correction has been
changed from 0.5 to 0 (professional version users will need to change this
manually, but the change will be automatic for standard version users). Also,
verification results from about 1200 forecasts over the last year here in
Atlanta suggest that GFS biases in cloud cover and precipitation (a previous
year of data had suggested the model was too cloudy and wet) have also largely
disappeared, so the bias correction setting for cloud cover, precipitation
intensity, and precipitation intensity skew have been changed from the previous
-3, 90, and 2, to -1, 95, and 1, respectively. This will generally increase
cloud cover by about 4% and precipitation by about 5%. Professional mode users
should consider their own accumulated experience as local effects can be important
- More thorough data on 700 mb
relative humidity in WXSIM was made accessible to wret.exe.
- The forest effect on snow cover
was increased somewhat.
- A bug in wret.exe that caused
values of UV index to be too high was corrected.
- In light of new data, the UV index
algorithms in WXSIM was revised generally downward by about 7 or 8 percent,
and the elevation effect part of this was improved also.
- The UV index algorithm used for
display on the main Data Entry form of WXSIM was found not to be consistent
with the one used in the output. These two instances of UV index now share
a common algorithm.
- An option was added in wret.exe
to include a numerical convective parameter in the lastret.txt file (created
when 'View Text' is selected).
- The default dew point depressions,
as functions of layer cloud cover, were changed for levels 2 through 5. In
particular, cloud cover of less than 10% now gives dew point depressions tending
towards 14, 18, 16, and 15 degrees Celsius for levels 2 through 5 respectively.
This was based on averages of all soundings from Athens, Georgia, for days
with less than 10% average total cloud cover, over a 6 year period.
- A new setting was added to the
Local Data Import form, allowing specification of a minimum sun altitude (default
10 degrees) for using estimated cloud and haze data from WXSIMATE. This is
useful because low sun angles yield relatively unreliable solar-radiation-based
cloud and haze estimates. The setting specifically refers to sun altitude
30 minutes before the forecast initialization time, because the default time
span used in WXSIMATE (for collecting solar radiation data for this purpose)
is the hour leading up to the forecast time.
- A new setting on tab 4 of the
Preferences/Settings form allows specification of a threshold value for combined
level 1 through 3 cloud cover (in percent), below which precipitation will
not be forecast, even if present in FOUS data or on the Interrupt Planner.
This is probably most useful in cases where the orographic downslope effect
is in use; the reduced cloud cover in such cases may well be accompanied by
an elimination of precipitation. The default value (and only value for standard
mode) is now 40%. If precipitation was previously supposed to be forecast
at a certain time, a small increase in cloud cover may be observed in the
forecast as a vestige of what would otherwise have been precipitation.
- The 'Reduce superadiabatic' feature
was modified by weakening the effect slightly, so that even with it active,
the near-surface temperature lapse rate will be allowed to exceed dry adiabatic
by a slight amount - and by slightly more than before.
- The 'enhanced maritime effect'
was expanded to include a reduction in the cooling effect of precipitation,
considering the fact that the nearby or surrounding sea is not made any more
wet by rain falling on it, and thus removing a component of evaporative cooling
that would exist for an inland site.
- A protection was added against
a very rarely encountered report of freezing rain with temperatures well above
Version 12.8.6 (March 11, 2011) had
the following change relative to Version 12.8.5 (described below):
- A protection in wret.exe, against
trying 'comparison to actuals' or 'auto select' when more than 5 items are
checked in either the 'temperature and thicknesses' or the 'other data' section,
has been changed to allow up to 10 items, which is the maximum anyway (5 of
which would show only in lastret.exe). Previously, if such a run was attempted
with more than 5 items checked, the program simply did nothing. Now it will
complete the requested task.
- A safeguard was added in wret.exe
against a 'division by zero' error during an 'auto select' run, in the rare
case that the average departures from normal of the warmer and colder halves
of the data points are identical. Now such an occurrence will simply generate
a slope of zero for the temperature error as a function of departure from
- A new feature was added to Preferences/Settings,
allowing the user to specify a description the density of forest (especially
evergreen) in the surrounding area, for modification of the effect of snow
cover. Some consideration had been given to this already, in the form of a
ground cover parameter included in the customization. However, this appears
not to have been sufficient for describing situations such as dense fir forest
in high northern latitudes, where the dark trees considerably mitigate the
cooling effect of the otherwise high albedo (reflectance) snow cover. Any
setting entered by the user is saved on exit.
- A small problem with snow:water
ratio as used during the calibration run was corrected (it had defaulted to
a value of 2 in most cases). This change will have only a very small effect
Version 12.8.5 (February 19, 2011)
had the following change relative to Version 12.8.4 (described below):
- A sophisticated and carefully
researched new algorithm replaces the former one for estimating wind gusts.
The new routine takes into account the user's choice of definition of gusts
(i.e. higest wind in a 10 minute period, versus highest in a 60 minute period)
and allows adjustment of gust factors by the user, who can also specify the
lowest speed wind gust to be reported in the plain text output.
- A caption, just under the site
information on the Data Entry form, now displays whether professional mode
is OFF or ON, and whether auto run is OFF or ON.
- A bug, which caused small errors
in the drawing of the upwind direction (thick arrow and dotted curve) on the
advection sites map, has been corrected. This would mainly have been noticed
in manual mode (or in auto run if you were watching very closely) and different
flow curvatures were being tried. It did not affect auto run forecasts, but
could have influenced user decisions when experimenting with flow curvature
- A bug, which could cause the program
to get into an endless loop of saying "Calibration Run" if the cor.txt
file was corrupt, has been fixed. Now, such corrupt files (how it got corrupted
is yet to be determined) will be identified as such, the user will be notified
by a message box, and the run will be allowed to complete, using default correction
factors of 0, 1, 0, and 0. At the same time, a more centralized error trapping
method was instituted, to hopefully make identifying any future run time errors
- A protection was added to guard
against unrealistic wind values that could result if either the localcal.txt
or localdat.txt files were somehow corrupted during or after an import of
local station data using WXSIMATE. This protection was added in response to
the only reported case of the problem, which produced a brief period of abnormally
- A bug, which could cause an 'invalid
property value' error if the Stop AM Rain refinement was chosen, has been
fixed. The error probably appeared mainly in the winter season, and this is
a summer season feature, which is probably why the bug took so long to show
up. Note that this feature boots up with default times, except in auto run,
where the settings are remembered from the last run.
- Wind chill wording was changed
to include both the lowest and highest values of each 12 hour forecast period
(when colder than a threshold of -3 C), with the term "ranging from
- The snow remembering routine was
changed to avoid errors which could occur with certain Windows regional settings
which use decimal separators other than periods. If the old format is encountered,
a message will alert the user to this fact, with instructions to temporarily
disable the routine to let a new forecast run, at which point it can be re-enabled.
- Wind gusts over 1 and 10 minute
and 1 and 6 hour periods were added to the display options in the retrieval
- A bug (which may have existed
for many years) involving wind chill in wret.exe was corrected. This bug had
caused erroneous graphical and text display of wind chill values when wind
speed units were other than miles per hour.
- Now up to 10 items from the temperature-related
options, and also 10 from the 'other' data options, can be chosen in wret.exe.
Only 5 from each group can be displayed as text or plots, but the others will
appear in the lastret.txt file. If you do choose more than 5, the program
will decide which 5 to display, as currently there is no mechanism for making
- Choices for data to display in
wret.exe have been rearranged into more logical grouping.
- Protection in the form of a message
box (manual mode only) and reasonable default values was added for extreme
wind speeds from potential misinterpretation of METAR or other ingested wind
- Megajoules per square meter were
added (to Watt x hours per square meter and Langleys) as an option (under
Preferences/Solar Energy Units) for output total daily solar radiation. A
similar addition was made to wret.exe (the retrieval module).
- Precipitation and total solar
radiation units were added to the hard copy printouts available for Plots
Version 12.8.4 (January 11, 2011)
had the following changes relative to Version 12.8.3 (described below):
- A bug, discovered in the 'snow
remembering' routine just introduced, has been fixed.
- The formatting of the snow depth
box on the snow/ice entry form has been changed to round off to the nearest
hundredth (this change prompted by the appearance of decimal values in this
form in some cases after use of the 'snow remembering' routine).
Version 12.8.3 (January 11, 2011)
had the following changes relative to Version 12.8.2 (described below):
- Further testing of item #7 for
12.8.2, below showed errors in the normal diurnal range of some sites. This
turned out to be due to mathematical errors out in about the 12th digit, perhaps
due to to the precision and type of the variables involved. Normally such
a problem would be trivial, but a condition (whether or not the variable's
value was exactly zero) that had been set made the effect much larger. This
has been corrected with a protection against the resulting extreme values.
Now both old customizations and future ones should function properly.
Version 12.8.2 (January 10, 2011)
had the following changes relative to Version 12.8.1 (described below):
- The tolerance for triggering a
message about sea surface temperature being out of range was increased from
2 Celsius degrees (3.6 Fahrenheit degrees) to 3 C (5.4 F).
- A typo ("Relativelymild")
in the plain text output was corrected. Also, freezing rain wording for metric
units had "above ground" added, for consistency with imperial units.
- Wind chill during the daytime
periods in the plain text forecast was changed to reflect the *warmest* value
during the day, with wording such as "Wind chill colder than
- The (somewhat rarely used) READY
data turns out to have changed format slightly at some point, which led to
WXSIM omitting precipitation while parsing. This has been corrected, and simultaneously,
arrays have been expanded to handle the 3-hourly READY data out to 192 (instead
of the previous 180) hours.
- A bug (starting with Version 12.8.1),
which kept wret.exe from recognizing old correction factors in forecasts,
has been corrected.
- Start and ending times for the
forecast run itself were added to the latest.txt (and archived versions) file.
- A parameter has been added for
future customizations that will permit slightly better matching of some sites'
climatological diurnal temperature ranges (thus affecting displayed normal
max and min temperatures).
- A bug (discovered as I was testing
(7), above), which allowed inaccuracies of perhaps a degree or two in the
displayed normal max and min temperatures (by not fully determining the normal
diurnal range as intended) has been corrected. This has virtually no effect
on forecasts and had only a very slight effect on the quality of some customizations.
Earlier customizations affected by this will now show more accurate climatological
- Top layer (the top one centimeter)
soil temperatures are now initialized more accurately due to improved interpolation
and extrapolation algorithms.
- A new parameter, called 'Base
insulating effect', has been added to the soil data form. The need for this
arose as I did additional testing on both summer and winter soil temperatures
in various scenarios, using data from the Soil Climate Analysis System (SCAN).
This appears needed to represent thermal effects (mostly simple insulation,
I believe) apparently due to grass turf ground cover. It should probably be
set to zero for truly bare ground, but otherwise, values around 2 seem about
right for a wide range of conditions.
- A option to 'Initialze with previously
forecast snow cover' (on the first 'tab' of the Preferences/Settings form)
has been added. This allows WXSIM to start a new forecast using the snow cover
from the last forecast run, specific to the date and time of the new forecast.
You can still override this by entering the new snow cover directly, but this
feature will be very useful if you must be away from the computer during a
series of forecasts where snow is accumulating and/or melting. In this case,
the snow/ice cover refinement does not need to be active (hightlighted red),
though is may be.
Version 12.8.1 (December 30, 2010)
had the following changes relative to Version 12.8 (described below):
- The interface for many of the
settings was considerably rearranged, by creating a new form, under a new
item called 'Settings' (under Preferences on the main menu bar). On this form
is a combination of the former text width form, the minimum UV and precip
form, the fog and frost options form, and the model bias form. Some items
from the Interrupt Planner were also duplicated for easy access, especially
for users doing mainly auto runs.
- Sliders were added (to the form
in (1), above - professional mode only) to control the strength of the 'allow
decoupling' and 'additional maritime effect'.
- Site and date specific temperature
variation data has been added to this new form.
- The ability to specify upslope,
downslope, and lake-effect directions for wind has been added. These features,
available only in professional mode, can alter cloud cover and precipitation
amounts derived from imported model data in order to model effects on a scale
smaller than that of the model (mainly GFS) data. Proper use of this feature
will require study on the part of the user over time, and controls are provided
to allow the user to tweak these settings based on accumulated experience.
- Optional wind and temperature
descriptors have been added for the plain text output. The wind part is fairly
straightforward ("breezy" for >12 mph, "windy" for
>17, and "very windy" for >25). The temperature part is very
sophisticated, taking into account not only actual temperature, but also wind
chill values and number of standard deviations from normal specific to the
site and date.
- Wording rules for precipitation
in the plain text output have been changed so that probablilities or amounts
will not be mentioned unless there is a specific reference to precipitation
or at least a chance of convection in the forecast.
- Changes were made to wxsim.exe
which now allow use of newly created (using wret.exe) bias correction factors
without having to restart WXSIM.
- Changes were made in wret.exe
so that, if the "learning" option is turned off in WXSIM, the effective
correction factors for those forecasts will be considered to be the default
- Protections (in the form of message
boxes) were added to wret.exe so that users are much less likely to take an
incorrect sequence of actions which might have led to an error.
- A bug, which could occasionally
carry over precipitation from the end of one forecast to the first line of
text of the next, has been corrected.
- A possible 'Invalid property value'
error when using imported precipitation data has been averted.
- An oversight which on rare occasions
could allow METAR reports of runway condition to be misread as temperature
and dew point (possibly leading to 'dew point cannot exceed temperature' message)
has been fixed.
- Another METAR import bug which
could also very rarely lead to a dew point being read as a barometric pressure
(hence triggering an 'unrealistc barometric pressure' message) has been fixed.
Version 12.8 (November 30, 2010)
had the following changes relative to Version 12.7.5 (described below):
- A new suite of calculations of
agricultural interest, such as soil temperature and moisture, and evapotranspiration,
was implemented, and is available in professional mode. A new menu item in
the main program was added to accommodate user defined choices of output.
These new output variables (23 in all) can also be viewed as plots or text
in the retrieval module (wret.exe). Further refinements and features can be
expected in upcoming versions.
- A message box which was new to
Version 12.7.5, but which I forgot to document below, was causing problems
for some users. This message was intended to detect if another version of
WXSIM was open, and alert the user to that fact. In some cases, the message
appeared inappropriately and interfered with auto runs. This "new"
feature has now been removed, as it may have caused more problems than it
- Two problems with temperature
forecasts for island, coastal, or near coastal areas were addressed (a typical,
but not unique problem region being New Zealand). One is that of too-high
maximum temperature forecasts, mainly in spring. The other is that of too-warm
minimum temperature forecasts on calm clear nights, just about any time of
year, but perhaps most prominently in winter. The first problem was identified
as an inappropriate lack of marine influence when winds were from the "inland"
direction, especially when water is not too far in the direction (as on an
island). The solution is an optional sea-breeze-like influence (but without
modification of wind), which can operate either with or without the existing
sea breeze routine (the effects are roughly additive). The other problem was
addressed by increasing the effects of the existing 'allow decoupling' routine
(check box on the Interrupt Planner), using an additional component to the
routine which specifically increases diurnal temperature range. Both of these
routines are influences by a new input on the form reached by selecting 'Min
UV and Precip, Sea Breeze, and Advection item under parameters. This new item
lets you define a distance to the far side of an island or peninsula, up to
100 miles (161 km) distant.
- A significant problem with the
"learning" routine ('auto select') in wret.exe was discovered and
corrected. This was actually making forecasts *worse* for some users. It manifested
in the slope of the error versus departure from normal line. The earlier "correction"
was exactly backwards, and either made too-extreme forecasts more extreme,
or too-moderate forecasts even more moderate (in terms of departure from normal
seasonal mean temperature). One indication of the problem was frequent appearance
of a message that the slope correction was 'out of range' and would be 'limited'
(which is a good thing, as the limitation kept the problem from getting too
far out of hand.
- A number of cosmetic and display
changes were made in wret.exe, including the addition of mean temperature
of a forecast period on the graph showing temperature errors versus day of
forecast. Also, the "proposed" line on the graph of temperature
error versus departure from normal now has a more clear meaning. It now shows
the correction that will be made in practice if the proposed values are accepted.
- The text width scroll bars in
both wxsim.exe and wret.exe were given greater ranges, in order to accommodate
different font sizes and resolutions that may be available with newer versions
- On the Text Width, Heat Index,
and Frost Options form (under Parameters), users can specify a choice of conditions
under which to display frost as an output in the plain text output. This includes
an option to mention frost only if it is "climatologically significant",
meaning unusual enough for the season to be "newsworthy". This decision
is guided by WXSIM's own internal estimate of the climatological probability
of ground frost occurring on the current date. NOTE - This feature has already
been present since about Version 12.7.2, but I forgot to describe it sufficiently
before. ANOTHER NOTE - I have become aware that, in many countries "frost"
refers speficically to the occurrence of freezing temperatures. This is NOT
the meaning in WXSIM, where it instead refers to a form of condensation (more
properly, "deposition") of water ice onto surfaces like grass or
cars. "Heavy" frost, here, means a lot of the white stuff, not necessarily
especially low temperatures.
Version 12.7.5 (July 2, 2010) had
the following changes relative to Version 12.7.4 (described below):
- Changes were made to the plain
text output decision algorithm, mainly to prevent mention of precipitation
chances below 20 percent when the 'Omit trace amounts or very slight chances
of precipitation' box is checked. This is actually a second attempt at the
fix in 12.7.3, which still had a loophole and was not fully successful.
- A bug was discovered in the sea
breeze routine, in which it wrongly used north as a default water direction
when reactivated during auto run. This has been fixed, as was a closely related
problem involving the mountain/valley breeze routine, where is had been 'forgetting'
the diurnal breeze amplitude.
- The Diurnal Breeze form (containing
both the sea breeze and mountain/valley breeze controls) now had a 'Reset
Defaults' button, which if clicked populates the form with the originally
customized data, including current seasonal sea surface temperature (adjusted
to site level, as always, with a lapse rate of about 3.5 degrees F per 1000
feet or 6.5 degrees C per kilometer).
- There is now a message box which
warns the user if, in auto run, the retrieved (at boot up) water temperature
is different from the default climatological value by more than 4.5 degrees
F (2.5 degrees C). This si intended to prevent the problem of unseasonal default
water temperatures being used in the forecast when users do not reset the
value reasonably often.
- A very small bug, which could
make temperature forecasts on subsequent runs using identical data different
by perhaps a couple tenths of a degree, has been fixed. It was due to an inconsistency
in how the 'air mass temperature' was determined the first time through, versus
on subsequent runs.
Version 12.7.4 (July 1, 2010) had
the following change relative to Version 12.7.3 (described below):
- Change #3 under Version 12.7.2
(below) was discovered to cause an occasional error #5 (invalid procedure
call or argument). This has been corrected, while preserving the new parsing
ability introduced in Version 12.7.2.
Version 12.7.3 (July 1, 2010) had
the following change relative to Version 12.7.2 (described below):
- A change in the plain text output
algorithm, introduced in 12.7.2, caused a change in the output in the case
of using the 'Omit trace amounts or very slight chances of precipitation'
box on the 'Minimum UV Index and Precipitation for Display, etc.' box. It
should now behave as before.
Version 12.7.2 was completed on June
29, 2010 and has the following changes relative to Version 12.7.1 (described
- An isolated instance of failure
to recognize commas as potential decimal separators (in certain Windows regional
settings) was corrected.
- An option (mainly for Canadian
users) to use humidex instead of heat index was added, and can be accessed
under Preferences on the same form as text width. Humidex was also added to
wret.exe's optional outputs.
- METAR barometric pressures failing
to use standard prefixes ("A", "SLP", or "Q")
are now read anyway. Also a default pressure of 29.92 inches of mercury (1013.2
millibars or hectopascals) is now assumed at the beginning of METAR import
in case no pressure reading is found.
- WXSIM now detects other open copies
in the same folder, or instances of failure to close the program properly,
and alerts the user to this with the choice to proceed or quit (and perhaps
either use or close any other open copies).
- WXSIM now optionally includes
frost descriptions in the nighttime forecast periods.
- The frost decision routine was
modified using additional data, including information on the difference between
'grass' temperature (within 10 cm of the surface) and 1.5 meter "shelter
temperature", from hisklim7.pdf
- The plain text output (saved as
plaintext.txt and also incorporated in some other products) now includes (optionally,
if Convective Bulletins are enabled under Preferences) mention of showers,
thunder, or severe weather if WXSIM considers the probability sufficiently
high, even if imported model data doesn't suggest measurable precipitation.
- A new option, activated by checking
the new 'Allow decoupling' box on the Interrupt Planner form, permits WXSIM
to decrease both maritime temperature-moderating influence and the strength
of warm air advection when the strength of (mainly nocturnal) temperature
inversions exceeds a certain, rather weak, threshold value. This effect increases
with the strength of the inversion and is therefore strongest on clear, calm
nights. It is most significant in coastal and near-coastal areas and its main
effect is to lower nighttime low temperature forecasts. This change was motivated
by reports of too-warm overnight lows, mainly in coastal areas, under clear
conditions with light winds.
- Made minor cosmetic and help files
Version 12.7.1 (February 20, 2010)
had the following changes relative to Version 12.7 (described below):
- Provided error handling in case
a printer is not declared. Now, a message will appear explaining the need
to do so, along with instructions for how to do so in control Panel.
- Fixed a bug which could cause
errors in the station precipitation amount in Comparison's in wret.exe for
users of Weather Display
- Made minor cosmetic changes.
Version 12.7 (February 15, 2010)
had the following changes relative to Version 12.6.3 (described below):
- A 'subscript out of range' error
that could have occurred when importing GFS data that is initialized after
the forecast (which can happen only if you are running forecasts after the
fact) has been averted.
- Another 'subscript out of range'
error that could have occurred when importing GFS advection data for a different
site has been averted. A message box will now appear alerting the user to
import fresh GFS advection data relevant to the current site.
- The optional GFS temperature and
dew point plots on the Output form's graph now have correct colors for the
current background color (an earlier coding problem had led to low-contrast
- Thunder and severe convection
outputs (the same ones displayable in wret.exe) are now written to the main
(not 'daily') .csv output file. Column headings help describe these roughly
- An option has been added to the
Auto Run form to execute a user-defined DOS batch file after auto runs or
after the user clicks 'Repeat' after a manual run. Possible uses might include
converting a .bmp file to a more compact format (like .png) using another
program, uploading files to the internet, or a combination of such actions.
A sample batch file, called latestbmppng.bat, is provided in the demo package
to instruct IrfanView Version 3.2 (see www.irfanview.com if you are interested
in obtaining this program) to convert the optionally produced graphic latest.bmp
to latest.png in the c:\wxsim folder.
- An option has been added (to the
Minimum UV Index and Precip form) to adjust the effectiveness of diurnal breezes
(sea breeze or mountain-valley breeze). This affects the diurnal wind vector
component and also (in the case of sea breeze) the direct effect on temperature.
It is strongly recommended that users research their forecast bias histories
before considering any such alterations.
- Another option added to the above
form adjusts the effectiveness of cold or warm advection. It is strongly recommended
that users research their forecast bias histories before considering any such
alterations. The only locations I know of at present that seem to warrantthis
intervention are in southern Greece.
- Various cosmetic changes were
made, including adding program-specific icons to the forms in both wxsim.exe
and wret.exe, and changing the background color of the help forms in both
programs from yellow to a less harsh tannish-orange.
- Changes were made to the vertical
lines on both the regular and comparison plots in wret.exe. On the regular
plots, the bright blue vertical lines (which did not consistently mark days)
were made a darker blue, and with other dark blue lines form an unobtrusive
finer scale (easily interpreted only when showing 2,3,4,6, or 8 days) than
the gray lines marking midnights. The comparison plots' blue lines were removed
and, instead, the dark gray lines now show midnights while the light gray
lines show every six hours.
- The fog sensitivity wording was
changed to put the default value of 45 (instead of the previous 50) in the
middle of the 'normal' range. Also, the description is now highlighted in
red if it is outside the range of 'low-normal' to 'high-normal'. Similar behavior
was also built in to the new diurnal breeze and advection adjustments, (6)
and (7), above.
Version 12.6.3 (November 22, 2009)
had the following changes relative to Version 12.6.2 (described below):
- A change was made to avoid an
'input past end of file' error (#62) when WXSIM tries to access GFS data for
advection, and it's not present. This error generally occurred if the 'GFS
for advection' box in WXSIMATE was not checked (it generally should be checked,
as this is a valuable source of data for most users). Now the program should
silently close the file with missing data without producing an error.
- A cosmetic error introduced accidentally
in 12.6.2 (the 2 PM check box on the auto run form had been shifted in front
of the 1 PM check box, rendering the latter invisible) has been fixed.
Version 12.6.2 (November 21, 2009)
had the following changes relative to Version 12.6.1 (described below):
- The ~Monotone check
box on the advection form was replaced by a Mono scroll bar which
allows mixing of the monotone and not monotone fits in various ratios, from
0% monotone to 100% monotone (in increments of 10%). The default value is
50%, which is generally a good compromise between getting the closest fit
to the data points and avoiding unrealistic extrapolations. This setting is
not saved. The 50% default is also used in auto run, unless Enforce
monotone is checked on the auto run form, or there is a strong inversion.
In these cases, the fit will be 100% monotone, meaning the advection profiles
for temperature and dew point will not have any slope reversals.
- The GFS advection data across
longitude 180 degrees (see #1 below) is now active on Chris McMahons
site, and the feature is now fully operational.
Version 12.6.1 (November 14, 2009)
had the following changes relative to Version 12.6 (described below):
- Support was added for advection
across longitude 180 degrees (such as in New Zealand with winds from the east),
in anticipation of expanded coverage in the GFS files for advection produced
by Chris McMahon.
- Colors were changed for the temperature
and dew point displayed by the 'Show GFS' button on the Output form. Previously
(by mistake) they were not matched properly with the blue or gray backgrounds
of the graph. They now will be displayed with the same colors as WXSIM's forecast
values, but with thicker lines.
- A scale was added for the wind
speed arrows on the advection data maps.
- Minor informational and cosmetic
changes were made to the Auto Run form.
Version 12.6 (September 19, 2009)
had the following changes relative to Version 12.5.4 (described below):
- Support was added for a new set
of GFS data kindly downloaded and culled by Chris McMahon. This is GFS data,
but now for a 20 x 20 degree grid surrounding the home site, so that GFS may
now be used for advection data, both initially and after wind shifts. This
feature should be especially useful for users outside North America (since
they do not have MOS for after wind shifts), but also for North American users
more than 2 or 3 days into a forecast, when MOS runs out. It will also be
helpful for users on islands or near coastlines, as data from ocean locations
will be available (the extent depending on my original allotment of surface
advection sites in the customization).
- GFS data can be used to fill out
the main Data Entry form values, with most of it coming from the new data
set, except for barometric pressure, which uses the previously existing set.
This is not the best way to fill out this form, since local METAR, synoptic,
or home station data would be more timely and accurate. However, for remote
sites with no surface data available, this should initialize the program well
enough for a good forecast in most cases.
- A time series of GFS temperature
and dew point data is now extracted, and can be displayed by clicking the
new 'Show GFS' button on the Output form. This makes an interesting, direct
comparison with WXSIM's own forecast on the Output form's graph.
- Internal changes in the auto run
routine were made, which may reduce or eliminate the possibility of certain
errors (especially number 52, 'Bad file name or number'). This change avoids
opening the FOUS and RAOB data display forms, which should keep things simpler
for Windows as it tries to thread the actions properly.
- A warning was added to all the
options under the Start menu to prevent users from starting a new forecast
without clearing the Ouput form from a prior run. This eliminates one possible
cause of Error #52 (see above).
- A new, very small form consisting
of a progress bar and percentage figure (appearing in the lower left part
of the screen, just above theWindows 'Start' button) has been added, to display
the percentage of the forecast complete so far, as it runs.
- There is now an option to 'Minimize
forms' on the Auto Run form. This causes almost all forms to be minimized
during auto runs. The exceptions are the small progress bar form (see above),
the file import progress bar form (which appears intermittently, and in this
case is moved to the lower left part of the screen, just above the new progress
bar form). And - in the case of 'Run Immediately' - the Data Entry form. In
a scheduled auto run, Data Entry will start out minimized if the program just
booted, and will otherwise remain minimized once it has been manually minimized.
These changes should enable users to perform other tasks on the computer while
WXSIM runs, with only minimal distraction.
- Choice of surface data source
(METAR, SYNOP, or GFS) is now saved only after import of data for the home
site, and no longer after advection data imports. The reason for this is the
complexity of choices now that all these (plus MOS) are now supported.
- The retrieval program wret.exe
now checks for completeness of the initialization file retini.txt to trap
errors resulting from damage (which a few users have seen, though the cause
is at present not known). If damage (usually missing lines) is detected, wret.exe
displays an error message to that effect and then attempts to restore the
file using a backup file, retinibak.txt, which in turn is created as a copy
of retini.txt if the latter is not damaged. Therefore, just one successful
load of the program is sufficient to establish the backup file. Meanwhile,
a copy of any damaged retini.txt file is saved as retinibad.txt.
- A new check box, 'Close program
after auto run', has been added to the Auto Run form. If checked, this will
cause the program to shut down right after the run is finished. The intention
here is to save users, who use System Scheduler (or similar) to open the program,
the trouble of also using such an external program to close WXSIM.
- Changes were made to wret.txt
to allow comparison of precipitation forecast to actual values, and also to
include averages as well as maximum and minimum values in the analysis of
this plus existing items. NOTE: In order to analyze precipitation for past
forecasts, WeatherLink users will need to run Import Data in WXSIMATE for
all past months for which analysis is desired. This is best done by manually
entering a date (make sure the Scheduler is OFF) early in the *following*
month so that a file will be created for the entire previous (desired) month.
Start in the past and work forward one month at a time. After this, the latest
two monthly files will be updated (including precipitation) every time Import
Data is run, so no further corrective actions will be needed.
- A small cosmetic change was made
to allow better readability of weather types in the saved bitmap plots in
- In wret.exe, the default directory
for the WXSIMATE-derived VWS and WeatherLink data files is now forced to the
current (boot-up) directory of wret.exe for using the Comparison feature.
This was already almost the case, but there was a loophole that might have
allowed the path name to change in some cases of analyzing forecasts in other
directories. The forecasts may be located wherever you like, but wxsim.exe,
wret.exe, and wxsimate.exe must all be located in the same folder (usually
- Capacity for number of combined
forecasts in 'Compare to Actuals' in wret.exe has been increased from 999
- A bug that could allow a 'File
already open' error in wret.exe - when changing weather station software types
and/or directories in wret.exe for Compare to Actuals - has been fixed.
- Changes were made in wret.exe
to allow proper display and use of certain items which may have been affected
by regional and language setting in Windows which use commas as a decimal
separator. There now should be no problems in the program related to this.
- A change was made in WXSIM to
hopefully preclude the possibility of a #Nul# value appearing for the diurnal
range multiplier in the .wxf files.
- A change was made to allow a tolerance
of 1 in either direction on 6 digit WXSIM registration codes, due to an apparent
computational uncertainty in the encryption algorithm.
- Changes were made to avoid errors
in case certain small, optional files (such as
skiplog.txt) exist but are empty.
- Clarified language on Auto
Compare form in the Retrieval Module (wret.exe)
- A safeguard was added to prevent
an error which could have occurred while using GFS advection data.
- Specified that the 'Retrieval
Module (wret.exe) not found' error message really require that error code
instead of assuming that this was the only such error that could occur.
Version 12.5.4 (July 8, 2009) had
the following changes relative to Version 12.5.3 (described below):
- A bug which could occur after
pressing 'Start Fresh' on the Output form has been fixed.
- Options were added to the Auto
Run form, allowing omission of either the log files (log.txt and latestlog.txt)
or the comma separated variable files (latest.csv and latestdaily.csv), or
both, from the forecast run. These files are not essential to operation and
their accessing (mainly in auto mode) may trigger sporadic 'Bad file name
or number' errors (#52) on certain computers. The reason for this is not clear,
but may be associated with having a number of other programs (perhaps especially
Terminate Stay Resident, or "TSR" programs) active. If you encounter
such errors, checking one or both of these new boxes may solve the problem.
- The wording of the command buttons
has been altered slightly to be more descriptive, and the (new wording) 'Disable
Auto Run But Keep Settings' button now allows any changes you made to settings
to be saved, both within the current session and on exit, for later boot-ups.
- The 'Activate scheduler on next
boot up' option now not only "sticks" (as it did before) upon leaving
the Auto Run form, but also "stays stuck" when the Auto Run form
Version 12.5.3 (June 29, 2009) had
the following changes relative to Version 12.5.2 (described below):
- A bug, which caused the program
to stall if both the 'skip this screen' and 'start scheduler on next bootup'
options were check, has been fixed.
Version 12.5.2 (June 25, 2009) had
the following changes relative to Version 12.5.1 (described below):
- There is now a search option in
the On-File Sites form, to locate a desired site by METAR, Name, State, or
Country. This is mainly for the me (the author) so that I can more quickly
find sites in my list of over 600. It may also be somewhat useful for the
few users who have several sites.
- The data is now read using separate
commands for month, day, and year, so that more date formats should now be
supported. The two options for display are still MM/DD/YY and DD/MM/YY. (This
change was actually implemented in 12.5.1, but I forgot to include it in the
- There is now an option to archive
forecast files in a directory other than that of the main program. You must
first create the folder. Then, after running a WXSIM forecast, click Save.
Then, on the form that appears, browse to and select the desired folder and
save the forecast to it. This change will be remembered for future saved forecast,
including automatically archived ones.
- There is now a check box on the
splash screen (of the pretty sunset) allow you to skip that screen in the
future. This was already possible in auto mode using the 'Start scheduler
on next boot-up' option, but it can now be done without automatically starting
- A bug, which sometimes caused
errors (mainly #52: 'Bad File Name or Number') in auto run (for those not
booting WXSIM with a third program such as System Scheduler) has been fixed.
Now, running WXSIM continuously through auto runs should be much more reliable
Version 12.5.1 (March 23, 2009) had
the following changes relative to Version 12.5 (described below):
- A bug, which allowed the time
step (determined by output interval and iterations per interval) to influence
the effect of the new temperature (slope) bias correction factor, has been
- Values of the new bias correction
factors, if used, are now included in the log.txt or latestlog.txt files (right
after urban heat island effect).
- A bug, which occasionally allowed
data on a second line of a synoptic report to be mistaken for a station code,
has been fixed.
Version 12.5 (March 21, 2009) had
the following changes relative to Version 12.4.5 (described below):
- WXSIM can now read bias correction
factors, determined from comparisons of archived forecasts with actual results
(if you have a home weather station working with WXSIMATE). These are activated
by checking the 'Use learned bias corrections' box on the form which appears
when you click 'READY/GFS bias factors' on the Import form. Note: This feature
is restricted to the professional mode, which all customers who ordered before
July 23, 2008 already have. Upgrading from standard to professional mode costs
$50 as of this writing.
- The retrieval module now has the
ability to create the correction factors (for temperature and dew point) referred
to above. The relevant new command buttons are 'Set as Earliest Date', 'Auto
Select', and 'Omit'.
- New blue text help items have
been added in wxsim.exe and wret.exe to explain the new learned bias correction
- A change was made to wret.exe's
Weather Display log file parsing mode, to handle uncommon log files which
omit decimal points in zero rainfall values. Previously, this could trigger
an error at line 578. Also, reading of values with commas as decimal separators
was more widely enabled, hopefully avoiding some occasional errors.
- Minor cosmetic changes were made.
- WXSIMATE no longer downloads NGM
FOUS or NGM MOS, as these no longer exist as of March 3, 2009. You can still
import them into WXSIM from old data files in case you ever want to dorun
retrospective historical runs.
Version 12.4.5 (January 17, 2009)
had the following changes relative to Version 12.4.4 (described below):
- A bug in the TTAA (RAOB) parsing
system, which could occasionally result in bad sounding data, has been fixed.
This error involved reading a wind field with a direction of 300 or 305 as
a height field for the 300 mb level.
- TTAA parsing was improved to read
wind speeds of over 100 knots.
- The range of the temperature controls
below the sounding on the upper air form has been increased from +/-20 Celsius
degrees to +/-35. The previous range had allowed occasional invalid property
value errors (#380) in extreme weather, when 1-Click was pressed, or in auto
- An attempt was made to eliminate
errors, mainly overflow (#6), occasionally seen when wret.exe is called in
auto run or by clicking the Repeat button. Specifically, some DoEvents commands
were added to the code, to hopefully get Windows to handle events completely,
in the order the code attempts to execute them. Feedback on whether this attempt
was successful would be helpful, as I cannot seem to replicate the errors.
Version 12.4.4 (January 16, 2009)
had the following changes relative to Version 12.4.3 (described below):
- A typo in wret.exe's sounding
plots was corrected ('850-500 mb thickness' was changed to '1000-850 mb thickness').
- Even more safeguards were instituted
to prevent loss of import file name. Note that if the name is somehow temporarily
lost, the replacement name will be c:\wxsim\wdata.txt, so that is a good name
to use anyway.
- A new check box, labeled 'ext
boot', was added to the Output form as an option under 'Graphic'. If checked,
wret.exe will NOT be run (as it normally would be to make graphics in auto
run or right after clicking "Repeat'); instead wret.exe will simply be
prepared to make the graphics and close the next time it is booted, either
manually or by an external program such as System Scheduler. The reason for
this option is an elusive (perhaps dependent on some unknown condition in
Windows) error (#6, Overflow) that some users have encountered at times. This
new check box provides an alternative way to automatically generate the same
plots and soundings. The help files were also updated accordingly.
- The diagnostic file replog.txt,
which was used to narrow down possible causes of the Overflow error described
above, was omitted.
Version 12.4.3 (January 14, 2009)
had the following changes relative to Version 12.4.2 (described below):
- More protections were instituted
against loss of import file name.
- A bug capable of causing an 'index
out of bounds of array' error, especially in subfreezing weather at sites
near sea level, was fixed.
- The retrieval module's sounding
bitmap naming convention was changed to simple serial numbers, instead of
skipping. You can still specify a skip interval to determine which soundings
are produced, but the numbering is now simpler.
Version 12.4.2 (January 13, 2009)
had the following changes relative to Version 12.4.1 (described below):
- Further work was done to prevent
erroneous reports of missing initial surface data.
- Additional protections were instituted
against loss of import file name and settings.
Version 12.4.1 (January 12, 2009)
had the following changes relative to Version 12.4 (described below):
- A bug (accidentally introduced
in 12.4) which caused occasional repeated lines of text on the output page
has been fixed.
- Another bug, which caused an erroneous
report of missing initial surface data, has been fixed.
- A change was made to further ensure
preservation of import file names in the event of errors, including the file
not being found.
- A new log file, called replog.txt,
was introduced into the code associated with the Output form's Repeat button,
to help track down the cause of a reported overflow error (#6) which I have
not been able to replicate. Any users who encounter this error should send
this file to firstname.lastname@example.org.
Version 12.4 (January 8, 2009) had
the following changes relative to Version 12.3 (described below):
- Snow level was added as an output,
in menu option #8, in the plain text output and as an output to .wxf files.
This item is calculated by working downwards through the atmosphere until
the first freezing level is found, and integrating temperature above freezing
with respct to height until an amount of melting energy, based on the precipitation
rate, in encountered. The heavier precipitation, the further below the freezing
level it melts. Snow level is defined here as the level at which a large majority
(perhaps 90 percent) of the precipitation is snow, though this is a difficult
and somewhat uncertain variable to calculate anyway. However, it should still
be quite useful for users in mountainous areas. Display parameters can be
set on the new, expanded version of the fog sensitivity form, under.
- The precipitation type algorithm
was tweaked in light of further research and to better coordinate with the
new snow level output.
- Slight changes were made to the
melting effect of frozen precipitation. This cooling was reduced by about
10% for sno or snow/rain mixtures. Also, an error which reversed the melting
effects of 'snow/rain' and 'rain/snow' was corrected.
- The latest.csv file (and any archived
or saved versions of it) has been augmented to include freezing level and
snow level. These are listed on the far right side.
- The retrieval module, wret.exe,
was expanded to accommodate snow level, which is now displayed in the 'thickness'
category. The graphical displays in this category are now more precisely labeled
on the plots.
- The sounding plots in the retrieval
module were changed to include snow level, and also to display height, temperature,
and pressure on the graph at the tip of the mouse cursor, to enable more precise
examination of the sounding.
- The retrieval module now allows
production of bitmaps of soundings, by checking both the 'Save Bitmap' and
'Inc Soundings' boxes on the Plots form.
- The retrieval module's bitmaps
are now cropped to reduce the size. They can be converted to other formats,
such as png, by using a third-party program such as IrfanView (www.irfanview.net).
- Changes were made to reduce the
likelihood of an error (other than File not Found or Bad File Name or Number)
causing a deletion of the name of the file to import.
GFS data consisting of zeros (as may happen if that system fails to actually
parse the data) is now treated as being simply absent. This may reduce the
possibility of any errors resulting from such an event.
- Additional notations have been
added to the plain text output to indicate when WXSIM fails to find various
data types - such as GFS, READY, or METAR, SYNOP, or local station data -
to serve as a warning of possible inaccuracy in the forecast.
- An error log (wretlog.txt) was
created for the retrieval module (wret.exe) to help diagnose any future errors
occurring in that program.
Version 12.3 (November 30, 2008)
had the following changes relative to Version 12.2 (described below):
- The boot up default values for
wind speed, haze, and level 2 and 4 cloud cover now represent rough climatological
normals for the site. Also, if no temperature data is manually entered or
imported (via METAR, SYNOP, or from local station data), temperature and dew
point will default to climatological normals for that time of day under the
given wind and cloud conditions. This makes more reasonable auto forecasts
in the rare cases in which data is missing. It also allows for easy production
of climatological normal temperature curves in a research or educational mode.
- Handling of date formats is now
more versatile, allowing use of yyyy-mm-dd format (used in Sweden, Poland,
and perhaps some other places). There are still only two format choices (month/day/year
and day/month/year) under Preferences, but WXSIM will now at least correctly
populate the entry form on boot-up regardless of Windows regional settings.
- A bug which caused errors and
loss of import form settings, after failure to find GFS or READY data in auto
mode, has been fixed. In auto mode, no warning will appear to alert the user
to the lack of data, but a message will be included in the latestlog.txt file
(and the forecast may be rather monotonous).
Version 12.2 (November 12, 2008)
had the following changes relative to Version 12.1 (described below):
- A new feature was added (on the
Interrupt Planner) for specifying the number of hours permitted to pass between
advection prompts. This is intended to facilitate updates to advection data
(mainly using MOS, which is available only for North American sites) in cases
where wind shifts remain below the specified tolerance. A good default figure
is about 30 hours.
- An option was added (on the Output
Form) to specify saving of only the .wxf files when archiving forecasts. This
is intended to minimize disk space usage for users archiving large numbers
of forecasts. Manually saved forecasts will continue to be saved as all five
file types even when automatically archived forecasts aren't.
- Improved error handling and messages
have been provided for the case of clicking 'Get Data' on the Import form
with a blank or non-existent file name in the box.
Version 12.1 (October 4, 2008) had
the following changes relative to Version 12.0 (described below):
- A problem, which could produce
'Invalid property value' errors after importing home weather station data
showing very heavy rain, has been corrected.
- A new safeguard was added, against
bad METAR wind speeds imported during autorun (for the home site). It defaults
them to 7 (mi/hr, km/hr, or whatever your units are), though this can then
be overwritten with your own local station data.
Version 12.0 (July 23, 2008) had
the following changes relative to Version 11.8.7 (described below):
- Slightly increased thresholds
for mentioning fog in the plain text output.
- Expanded use of 'slight chance
of' precipitation to include the lower part of the range previously covered
by 'chance of'.
- Added an option (under Preferences,
along with the existing minimum UV index threshold) for omitting mention of
very light or low probability precipitation from the plaintext output.
- Added site, date, and time information
to the Comments section of saved forecasts.
- Slightly reduced severity of convective
bulletin outputs for Northwest European mode (in both wxsim.exe and wret.exe)..
- Added information on some forms,
including clarification of the use of certain controls.
- Made numerous changes to facilitate
the use of different registration codes for different levels of use: standard
- Changed the demo cty.fdt file
to include just two sites: Atlanta - which illustrates professional mode -
and Marks Point, Australia, which shows standard mode.
- Updated price structuring to cover
four combinations of mode and of level of customization (basic and enhanced).
- Updated surface and upper air
databases used in customizing WXSIM.
- Changed the TM for the intended
WXSIM trademark to ® indicated the recent registration of WXSIM with the
United States Trademark and Patent Office.
Version 11.8.7 (June 27, 2008) had
the following changes relative to Version 11.8.6 (described below):
- Added the ability to read Dobson
unit values for up to 10 days, to be used in UV index calculations. These
values can be obtained from web sites (see blue text help for Ozone on Data
Entry form) and used to create a simple data file. A sample of such a file,
dobunitsAtl.txt, is now included in WXSIM's distribution and upgrade packages.
- The UV index algorithm now includes
reflected radiation off of snow cover, plus some consideration of surface
type (forest, grass, desert, etc.).
- Changed the interpolation scheme
for determining level 1 temperatures from GFS or READY data, in order to avoid
some bad results that could previously occur when surface pressures are very
- Made forecast log show correct
- Allowed for comma as the decimal
separator in the Distance Ratio item on the Advection form.
Version 11.8.6 (February 23, 2008)
had the following changes relative to Version 11.8.5 (described below):
- MOS advection in auto run after
wind shifts now defaults to using smooth curve fit, with 'enforce monotone'
if you so chose on the Auto Run form. Previously, it defaulted to a best fit
line, which appears to have subdued temperature advection after sharp frontal
passages too much.
- The retrieval module (wret.exe,
accessible from the main program via File/Retrieve) now enables comparison
of previous forecast with Ambient's Virtual Weather Station software, in addition
to Weather Display and WeatherLink.
- The help files were updated to
reflect the above changes.
Version 11.8.5 (January 21, 2008)
had the following changes relative to Version 11.8.4 (described below):
- The suffix 'NDV' (No Directional
Variation) is now understood by the METAR parsing routine, as applied to visibility
- The 'maximum distance' value (which
you can control with a scroll bar on the Advection form) now applies to the
cutoff time for advection (when you can choose to continue with a decay).
Previously the maximum distance simply determined which points to leave out
of the curve fit. This change should help limit temperature excursions in
cases of sparse, inappropriately fit data, especially in auto run, when you
are not there to oversee the profile.
- The auto run form has a new check
box option for enforcing the monotone condition on smooth curve fits in initial
regional data advection in auto run mode. Otherwise, WXSIM decides between
monotone and not monotone fits based on the amount of temperature inversion,
with monotone applied only if a significant inversion exists. As in (2) above,
this change is intended to reduce strongly curved advection profiles, which
can result from sparse data (such as near coasts).
- The help files were updated to
reflect (2) and (3) above, and generally explain auto run advection options
Version 11.8.4 (January 14, 2008)
had the following changes relative to Version 11.8.3 (described below):
- Checks were added to prevent use
of regional data advection in auto run mode when no sites (METAR, SYNOP, or
MOS) are found more than one fifth the maximum advection site distance (which
you can set on the Advection form). This should prevent some unrealistic temperature
excursions that were occurring in auto run, mainly for some near-coastal sites.
- Regional data advection is now
weakened in cases of poor flow curvature fits. Specifically, flow fits of
90 percent or better remain as they were. Flow fits below 90 percent are weakened
in such a way that, for example, a 45 percent fit now has 71 percent as much
effect as previously.
- The message box saying that MOS
data has run out now appears even if the user makes repeated attempts to use
this data; previously it had appeared only the first time). In such cases,
the Import form is now closed to allow immediate access to the Advection for,
to allow a new choice.
- The "sleet/mix" precipitation
type no longer contributes to above ground freezing rain accumulation.
- The summary.txt file is now saved
in the directory in which WXSIM was first booted up (usually c:\wxsim), which
could in some cases be different from the current directory at the time the
file is saved.
- The version number in the log
file was updated to 11.8.4 (it had been left as 11.8.2 in Version 11.8.3).
Version 11.8.3 (December 27, 2007)
had the following changes relative to Version 11.8.2 (described below):
- The auto haze routine was improved
based on a recent analysis of up to 25 years of visibility data for a few
U.S. cities. Generally, the haze amount is somewhat less sensitive to wind
speed and recent precipitation than before. Also, a new algorithm allows the
initial (input or imported) visibility and associated haze value to decay
towards the auto haze amount, rather than abruptly changing to it.
- A new output file, called summary.txt,
is now produced with each forecast and placed in the directory with WXSIM.
This file is a copy of the "Summary" , "Supplemental data",
"Nightime lows and daytime highs", and "Totals" which
appear in the original forecast.
- The criteria for the plaintext
output's phrases "temperatures rising after midnight" and "temperatures
falling in the afternoon" have been changed slightly, so that average
temperatures must rise or fall by at least 0.3 Celsius degrees (0.54 Fahrenheit
degrees) to trigger inclusion of these phrases. This will prevent the phrases
from appearing when temperatures are almost steady.
Version 11.8.2 (December 1, 2007)
had the following changes relative to Version 11.8.1 (described below):
- A bug, preventing second and subsequent
scheduled auto runs with WXSIM remaining open, had appeared first in version
11.8. This resulted from a mismatch between a timer in the program and the
way it was being read. It has been fixed.
- A bug which prevented MOS data
from being read on the first try after a "MOS not started yet" message,
has been fixed.
- Additional diagnostic items were
added to the log file.
Version 11.8.1 (November 25, 2007)
had the following changes relative to Version 11.8 (described below):
- A bug introduced by a changed
yesterday was fixed. In particular, users with day/month/year format would
see an error message about the month being greater than 12 pop up incorrectly.
The protection feature still exists, but the problem at boot up has been eliminated.
- Additional small changes were
made to prepare for the multi-site controller under development.
Version 11.8 (November 24, 2007)
had the following changes relative to Version 11.7.3 (described below):
- The algorithm for interpreting
FOUS relative humidities as cloud cover was modified for the second time this
year (see item #5 for Version 11.7.3, below). Specifically, in light of about
two months of additional data, cloud cover was increased slightly - about
halfway back to what it had been before Version 11.7.3.
- Based on data from many users,
including several months' worth that I had collected this year, a change was
made to make spring slightly warmer and fall slightly cooler than before.
- Also based on the data above,
slight changes were made affecting the shape of the diurnal temperature curve.
The main effect that the afternoon high temperature will occur about 10 minutes
- Based partly on the data above,
and also on an extensive review of verification statistics for the GFS model
since the former "parallel" version became the operational (and
improved) one on May 1, 2007, the default model temperature bias adjustment
was changed from +1.0 to +0.5. The blue text help for that item was also changed
to reflect this. Official GFS verification data can be found at STATS
- The program version number is
now included in the log files. Also, most error messages will now be recorded
in these log files.
- An error message will now inform
the user if an attempt is made to enter a date with a month number greater
than 12. This should catch most instances of entering day/month/year dates
when the format under Preferences is month/day/year. If this occurs, the usually
solution would be to change to the date format you want under Preferences.
- A rare error in the routines for
determining how old RAOB or READY/GFS data is has been corrected. Specifically,
in earlier versions, a forecast start time between midnight and 1 AM, using
daylight savings time, was interpreted by these routines as belonging to the
previous day. WXSIM now understands the distinction and should determine the
ages of these data blocks properly.
- Non-visible changes now enable
use with a third program (in addition to WXSIM and WXSIMATE), currently under
development, for sequentially running forecasts for multiple sites.
- A customizable adjustment was
added to account for variations in the evening temperature curve. Most sites
will not need this, but for a few future sites it may improve temperature
- Two minor bug fixes, involving
inconsistency between scrolling and clicking the default frontal codes scroll
bar, were fixed.
- A quick start guide (for both
WXSIM and WXSIMATE), illustrated and in either PDF or Microsoft Word format,
is now available from www.wxsim.com/downloads.
Version 11.7.3 (August 18, 2007)
had the following changes relative to Version 11.7.2 (described below):
- A bug - which could cause an "overflow"
error (error #6) when the Multi-Curve smoothing option was enacted with insufficient
regional data - was corrected.
- A bug - which could cause an "invalid
use of null" error (error #94) when using FOUS without precipitation
simulataneuously with READY/GFS data - has been corrected.
- Latest.txt (and any name under
which you choose to save a forecast) now will contain complete data even if
the "TEXT BOX FULL" message appears on the screen. (That message
is not an error, but simply results from Visual Basic's 32 KB text box size
limit, and can be avoided by choosing either a shorter forecast or a longer
output time interval).
- A couple of typographical or formatting
errors in the introctory material were corrected.
- Changes were made in the way WXSIM
uses FOUS data to predict cloud cover. These changes were based on a careful
study forecast versus actual solar radiation in over 100 forecasts, including
55 re-run forecasts after modifications. The previous algorithm, based on
comparison of FOUS relative humidities with METAR reports, had resulted in
too-thick cloud cover and too-low solar radiation forecasts, which led to
reduced diurnal temperature range during the first day or two of forecasts
for many U.S. users (as elsewhere FOUS is not available). The most significant
error had been too-low summer high temperature forecasts. This correction
should make FOUS a more dependable and useful adjunct to the GFS or READY
component of imported model data.
Version 11.7.2 (June 9, 2007) had
the following changes relative to Version 11.7.1 (described below):
- A bug which prevented the WXSIM
from properly 'remembering' the 'Stop AM Rain' setting was corrected.
- A bug which could cause an error
when WXSIM attempted to use 'remembered' Recent Precip settings was corrected.
- The wording of the message box
regarding 'Yes/No' refinement(s) still being activated and warning that values
must be reset or reviewed (as some may be quite erroneous) has been made more
explanatory. This issue is bypassed when using auto run, with old (but possibly
no longer correct) data in use.
Version 11.7.1 (June 5, 2007) had
the following changes relative to Version 11.7 (described below):
- A bug in 11.7, which left temperature
and precipitation column headings in the new 'daily.csv' file as 'deg F' and
'inches' when metric units were in use, has been corrected so that they will
read 'deg C' and 'mm'.
Version 11.7 (May 31, 2007) had the
following changes relative to Version 11.6.1 (described below):
- A new comma separated variable
(.csv, capable of being imported into spreadsheets such as Excel) file was
introduced, containing a wide variety of data in a daily summary format. This
file, whose name ends with 'daily.csv', complements the existing and much
larger .csv file containing almost all output data.
- Most of the refinements (in particular:
Auto cumuls, auto stratus, auto haze, recent precip, snow/ice cover, recent
temps, diurnal breeze, and stop AM rain) now have settings saved on exit.
This is really intended for use in auto run mode, as these should ideally
be set by the user at run time. To allow the settings to 'stick', the 'Activate
scheduler on next boot-up' box must be checked and the 'Use Above Settings'
button must be clicked on the Auto Run form. One item that is not saved is
the last 24 hours max and min temperatures (which are not recommended for
general use, anyway) on the Recent Temperatures form. Also, the message (appearing
if not in auto mode with scheduler activated and splash sceen skipped) warning
of old diurnal breeze data is separate from the warning about the other refinements.
- Minor cosmetic or instructional
changes were made, and a bug resulting from running comparisons in the retrieval
module (wret.exe) with bad or 'gappy' WeatherLink data was corrected by changes
to WXSIMATE rather than in wxsim.exe or wret.exe.
Version 11.6.1 ( April 7, 2007) had
the following changes relative to Version 11.6 (described below):
- A bug was corrected, which had
caused an error when data was imported after setting a negative precipitation
skew setting in the READY/GFS Bias Factor.
- Meters per second are now displayed
as "m/s" instead of "mps".
- The retrieval module (wret.exe)
was updated to include the changes in WXSIM's UV index.
- The help file wxsimhelp.doc was
updated to include information on the READY/GFS Bias Factors.
Version 11.6 (April 6, 2007) had
the following changes relative to Version 11.5.1 (described below):
- Model data (READY or GFS) imported
to the Interrupt Planner is now subject to bias adjustments on upper temperatures,
cloud cover, and precipitation. To access these settings, click the new "REAGDY/GFS
Bias Factors" button on the Import form. Settings are saved on exit.
- Default frontal codes now include
some consideration of current above or below normal temperatures, so that
a "return to upwind normals" assumes that "normal" includes
a fraction of the home site's departure from normal. This should make default
advection somewhat more accurate than before during periods of abnormal weather,
by allowing a bit more persistence of the abnormality.
- The UV Index algorithm was altered
based on further study of a variety of sources of data. The general effect
will be to lower UV index slightly, mainly with low sun angles.
- The Dobson Units setting on the
Entry form is now saved on exit.
- The lower limit for display of
UV index in the plain text output is now user-defineable, under Preferences
on the Entry form.
- A very slight adjustment was made
in the program, producing a barely noticeable increase in spring temperatures
and drop in autumn temperatures.
- An adjustment was made in the
program to lower dew points very slightly, based on a consensus of user feedback.
- A rare bug - in which an infinite
loop error when negative wind speed in advection sites was encountered - was
corrected. Such erroneous winds are now set to zero.
- A bug, resulting in an "Invalid
Use of Null" error message and occurring with initial precipitation,
- The "No data found for these
sites" message during auto mode has now been more thoroughly suppressed
(see #5 under Version 11.5.1, below).
Version 11.5.1 (March 3, 2007) had
the following changes relative to Version 11.5 (described below):
- The precipitation description
MIX now no longer leads to mention of freezing rain in the plain
text output unless the temperature was actually below freezing at the time.
- Initial snow cover is no longer
included in the first period accumulation in the plain text output.
- A bug, which kept snow accumulation
units on the snow/ice cover entry form from properly switching between centimeters
and inches, has been corrected.
- The isolated METAR signifier T1
now will not be mistaken for the first two characters of an extended temperature
field (which can also start with those two characters).
- (The No data found for these
sites message (after attempting to import regional advection sites)
has been suppressed while in auto mode. In this case advection will default
to either Default (frontal codes) or Neutral, according
to your earlier specification on the Auto Run form. This should prevent many
cases of stalling while in auto run mode.
- Maximum UV index for the day has
been added to the plain text output, as long as it exceeds 5.5.
Version 11.5 (February 10, 2007)
had the following changes relative to Version 11.4 (described below):
- Item #4 in the revisions in Version
11.4, below, was not completely corrected in Version 11.4. A further change
was made in 11.5 so that it will work as intended.
- The METAR signifier "NCD"
is now recognized, as meaning "no clouds".
- Some changes were made to the
FOUS and Interrupt Planner shower options. In particular, the Interrupt Planner
showers now fall one third of the time, rather than one fifth (several versions
back, it had been one third), but about 9 minutes later, in order to display
the precipitation even with one hour output intervals (with one fifth, the
showers were often missed in the output). To partially compensate for the
slightly reduced daytime highs with the longer showers, the increase in cloud
thickness due to precipitation was decreased slightly. Also, FOUS and Interrupt
Planner showers now work together in a complex, but more accurate (than before)
- A minor bug, involving cloud thickness
after precipitation, was corrected.
- Minor cosmetic changes were made.
- Slight tweaks were made to the
advection routine and the diurnal range. The only noticeable difference should
be a slight reduction in the initial strength of advection (or in cases of
very steep temperature gradients), generally amounting to about one or possibly
two degrese Fahrenheit warming at 12-24 hours in strong cold air advection,
for example. These changes were made after extensive testing on historical
and recent operational data in Atlanta, plus consideration of feedback from
users in other regions.
- A change was made in the default
frontal codes routine to slightly decrease temperature gradients. This probably
now makes the default frontal code option superior to neutral advection after
wind shifts, when no MOS data is available.
- The Help item on the Data Entry
form is now more informative, including mention of the wxsimhelp.doc file,
where all the blue-text help items are presented in an organized form.
Version 11.4 was (December 30, 2006)
had the following changes relative to Version 11.3 (described below):
- There is now an option on the
Auto Run dialog form allowing the the Scheduler to activate on the next boot-up
of WXSIM. This allows starting by an external program, such as System Scheduler,
skipping the start-up splash screen, and going straight into auto run mode.
- A log file (latestlog.txt) is
automatically created with each run, showing virtually all significant user
actions (and some program-directed ones). This is intended mainly for diagnosis
of problems, but can also serve as a simple record of how the run was made,
especially as it is archived and time stamped if you choose to archive the
- The menu item 'Customize' was
renamed 'Preferences', to avoid confusion with the customization process involved
with program registration.
- Auto run now distinguishes between
lack of MOS data on wind shifts due to being before, versus after, the start
of the data. Now it will read MOS in spite of an earlier finding that it hasn't
- Precipitation with chances less
than five percent is now not mentioned, either as a weather description, or
as a precipitation amount, in the plain text forecast.
- Persistent moderate to dense fog
now precludes mention of sky condition in the plain text forecast. This is
to avoid such combinations as "Sunny. Dense fog.". Also, a new category,
"moderate fog" was added, along with other slight wording changes.
- Several message boxes regarding
READY data were modified to include the GFS option.
- If used to import local station
data, WXSIMATE now produces a file called locallog.txt, containing the same
information it displays in the program itself. Also, wording of some error
messages in WXSIMATE has been improved.
Version 11.3 (November 8, 2006) had
following changes relative to Version 11.2.3 (described below):
- The ability to use GRIB-derived
GFS model data - downloaded, processed, and made available on the internet
by Chris McMahon - was added. Other changes made to accommodate this were
the expansion of the number of interrupts of each item on the interrupt planner
from 35 to 62, and the ability for WXSIMATE to download site-specific GFS
data for use in WXSIM.
- A couple of related bugs in the
retrieval module (wret.exe), which caused high and low temperatures and dates
to be shifted relative to each other for forecasts made between 11 PM and
midnight, were corrected.
- A bug in the comparison feature
of the retrieval module, which caused a failure to properly read home station
(Weather Display or WeatherLink) in forecasts spanning two months, was corrected.
- Temperatures and dew points in
U.S. METAR reports are now consistently and properly rounded off to whole
number Fahrenheit degrees in reports with the extended temperature section.
Previously, these would sometimes be reported differently by one tenth of
- Temperatures and dew points parsed
from synoptic data now have leading zeros omitted.
- 24 hour max and min temperatures
from local station import are now displayed on the Recent Temperatures form
even if they are not checked for use.
Version 11.2.3 (October 2, 2006)
had following changes relative to Version 11.2.2 (described below):
- Changes were made to accommodate
a recent (September 28) change in the READY datas header. WXSIM can
still recognize the older format as well, in case you want to re-run old forecasts.
- A bug, which could allow certain
METAR station codes to be read as weather type abbreviations, was corrected.
Version 11.2.2 (August 19, 2006)
had the following changes relative to Version 11.2.1 (described below):
- A bug, resulting from the addition
of a few incomplete entries to the NWS's MOS data files, has been fixed. This
had caused a 'Bad sky cover data' message box during MOS import for advection.
WXSIM now ignores these non-standard MOS entries.
- Any actual bad sky cover data
now encountered will default to partly cloudy, instead of clear.
Version 11.2.1 (August 17, 2006)
had the following changes relative to Version 11.2 (described below):
- A bug, which caused the plain
text output wind direction to always be 'north' when the diurnal breeze routine
was in effect, has been fixed.
Version 11.2 (August 12, 2006) had
the following changes relative to Version 11.1 (described below):
- A bug in the retrieval module,
which prevented changing the directory for Weather Display forecast comparison,
has been fixed.
Version 11.1 (August 11, 2006) had
the following changes relative to Version 11.0.2 (described below):
Version 11.0.2 (August 5, 2006) and
has the following changes relative to Version 11.0.1 (described below):
- The retrieval module's comparison
feature was expanded to include input from Davis WeatherLink files, via a
new feature in WXSIMATE which saved files in text format as they are read
for local station import.
- The ability was added to list
the files being compared and/or combined in the retrieval module.
- Compared and/or combined data
in the retrieval module in the retrieval module can now be saved as a spreadsheet-viewable
- The 'Combine' check box now maintains
its state (checked or unchecked) between comparison retrievals in the retrieval
- The second weather text item now
appears in WXSIM's saved forecast .csv files (it was intended to appear in
earlier versions, but failed to).
- The column headings in WXSIM's
saved .csv files are now left-justified (instead of right-justified), to make
them more visible.
- Enabled printing of plain text
forecast with 'Graph and Summaries' option (in addition to the other options).
- A bug, which could cause repeated
dates when retrieving forecasts made using daylight savings time, was fixed.
Version 11.0.1 ( August 2, 2006) had
the following changes relative to Version 11.0 (described below):
- A bug, which kept files from being
archived properly when the 'Quit' button was used, was corrected.
- A bug was fixed in wret.exe, which
had caused occasional scale problems when viewing comparison plots of relative
- On the form for naming saved forecasts,
the default name was changed from 'latest to latest (leading apostrophe removed).
Version 11.0 (July 25, 2006) had
the following changes relative to Version 10.6 (described below):
- An Auto Run option (under the
Start menu) has been added, allowing almost all features of WXSIM to be used
either for an immediate run or at user-prescribed times. In conjunction with
these changes, WXSIMATE can now import data at prescheduled times as well,
and the retrieval module, wret.exe, can be set for brief automatic boot-ups
and shut-downs to save bitmap graphics of forecast plots.
- A plain text forecast, with wording
somewhat similar to zone forecasts from the U.S. National Weather Service,
now appears at the end of the previous text output, and is also saved as a
file called "plaintext.txt".
- A global warming option (with
the option to switch on or off under the Customize menu) has been added. It
affects customized climate data, the world climate data grid, and radiative
properties in the program itself. It is normalized to approximately the year
1995, meaning dates with that year will have neutral effect.
- The default frontal codes algorithms
were improved using a large amount of climate data for several U.S. cities.
- The precipitation probability
algorithms were improved by mixing the existing routine with another, seasonally-dependent
estimate using the relationship between amount of predicted precipitation
and the probability of any measurable amount actually occurring. This relationship
was derived from both historical climate data from several U.S. cities and
results from about 400 forecast-days in Atlanta.
- An option was added to the retrieval
module (wret.exe) to allow comparison of previous forecast data with actual
data logged on home weather stations. Currently it requires the use of Brian
Hamilton's Weather Display program's log files, but I hope at some point to
add support for Davis WeatherLink .wlk files as well. A great deal of statistical
data can be gleaned from this feature, which may help with future customizations
and, in some cases, possible tweaks of existing ones.
- A problem with parsing certain
Italian METARs was corrected.
- WXSIM's Daylight Savings Time
check box's contents are now saved for the next boot-up.
- Several aspects of FOUS use are
better handled now, including dependable disabling of the routine if no data
was imported, and saving of settings for the next boot-up. FOUS can also now
produce more than one wind shift if allowed to do the first one.
- The Search routine on the Advection
form now properly imports MOS (instead of METAR) as the default after wind
shifts and correctly resets the number of sites found to zero in between searches.
- A new, optional setting allows
automatic archiving of forecast data files, using the format fyymmddhh in
front of the .txt., .csv, and .wxf formats. A similar setting in WXSIMATE
allows archiving of data files in the format dyymmddhh.txt.
- The retrieval program now automatically
defaults to the file latest.wxf on boot-up, though you can change the file
to any forecast you've made, as before.
- The apostrophe in front of the
default saved file name "latest" has been removed, as has the one
in front of the retrieved data file name "lastret".
- WXSIMATE can now import local
station data over the internet, given a root URL as the path.
- A couple of background bugs (including
a redundant variable name) were corrected.
- Various minor cosmetic and documentation
changes were made to all three programs: wxsim.exe, wret.exe, and wxsimate.exe.
- The help files and manual were
updated to reflect changes.
- A copy of the custinit.txt file
(which contains your personal boot-up settings for WXSIM) is saved, as custinitbak.txt,
in case the file ever gets corrupted or you wish to return to the settings
you had before a run. To restore the previous values you would simply rename
custinitbak.txt to custinit.txt.
Version 10.6 (January 23, 2006) and
has the following changes relative to Version 10.5 (described below):
- All of the slider controls were
changed to horizontal scroll bars, thus reverting to the form in all versions
prior to 10.0. There are two reasons for this. First, and most importantly,
I learned that installation of Microsoft Office XP or MS Office 03 apparently
deletes (from Windows/System32) the comctl32.ocx which the slider control
requires, thus leading to an error in WXSIM. By switching to the scroll bars,
this error should be avoided. Second, the scroll bars allow finer control
of the values they represent.
- A rarely encountered bug, in which
RAOB data segments could be mistakenly read as buoy data (if the digits happened
to be the same as the WMO synoptic code of the buoy), has been fixed.
- Minor cosmetic changes were made
in a few places.
Version 10.5 (January 16, 2006) had
the following changes relative to Version 10.4 (described below):
- A new control, for 'Maximum Distance'
was added to the advection form. This allows you to limit consideration of
advection site data to only those less than the upwind distance you specify.
In particular, this applies to the various smoothing routines (working on
data points from Regional Data, Two Upwind Sites, Frontal Codes, and Direct
Click) and also to the speed ('Spd') and flow fit ('%') figures found above
the 'Search' button. The straight line (segment) fit is unaffected.
- The 'Difficulty reconciling total
cloud cover with upper level relative humidities' message had been coming
up too often. This is because the GFS READY meteogram data always seems to
start with .000 as the cloud cover, before becoming reasonable with the very
next report. WXSIM now overlooks the problem if it occurs only on the first
entry (which has little effect on the output).
- I discovered that the (rarely
used) 'Two Upwind Sites' advection option was not functioning. This has been
- Minor cosmetic changes were made
to the retrieval module, wret.exe.
- Blue clickable page numbers were
added to the Table of Contents of this manual to allow instant jumps to specific
Version 10.4 (December 29, 2005)
had the following changes relative to Version 10.3 (described below):
- The handling of level 1 temperatures
entered on or imported to the Interrupt Planner was improved. Formerly, the
values were interpreted as actual level 1 temperatures. This is still the
case if you clicked them in yourself, but now READY-based temperatures take
into account the actual pressure level(s) (i.e. 925 mb) and adjust accordingly
to the level 1 pressure in WXSIM at the time.
- A set of options for use of level
1 temperatures (see above) was added. Now the temperatures can be ignored
("0%"), so that WXSIM's own routines are in charge, they can be
fully used ("100%") so that WXSIM will follow them very closely,
or they can be partially considered ("50%") so that WXSIM uses a
compromise between its native figures and those from the Interrupt Planner.
My current thinking is that the "50%" option may be best on average.
However, this is a new option and I am not yet sure if it will be truly advantageous.
It does *not* always yield temperatures halfway between the other two options.
- A bug was fixed involving the
Diurnal Breeze option. In the original changeover to versions 10.6, an oversight
left the Mountain/Valley Breeze routine out of consideration for the default
diurnal breeze (the other option being Sea Breeze, which is the default unless
your customization contains specific topographic data for the Mountain/Valley
Breeze). This has been corrected.
- A slight change was made to the
interpretation of FOUS and READY based winds. In particular, non-100% wind
correction factors now use slightly different factors for winds of different
speeds. Light winds (below about 9 mph) are adjusted by relatively larger
amounts than are stronger winds. This change was motivated by my experience
that wind speed differences are best characterized as a sort of mix of additive
and multiplicative corrections. Places averaging 80% of standard winds, for
example, might show 7.2 mph (80%) when standard winds are 9 mph, but 3.5 mph
when standard winds are 5 mph (70%) and 17 mph when standard winds are 20
- A message box was added to warn
against use of METAR or SYNOP surface data for advection, after the forecast
run has already started, such as after a wind shift interrupt. Such use was
formerly discouraged only by the automatic switch to MOS as the default source
for regional data advection. METAR and SYNOP import at this point are still
allowed, but should be used only rarely, for instance in cases of almost immediate
wind shifts (i.e. an hour or two into the forecast run).
- Various minor cosmetic changes
were made, mainly to some text boxes which weren't wide enough to hold some
of the values that might be encountered.
Version 10.3 (November 23, 2005)
had the following changes relative to Version 10.2 (described below):
- A new option was added to the
regional advection data routine choices. This is 'Multi-curve fit', which
blends two of the 'Smooth curve' solutions - one for the nearest half of the
advection sites and one for the farthest - using a weighted average. The '~Monotone'
box can be checked or left unchecked, as it still applies to the far-half
smooth curve solution.
- A small correction was made to
the root-mean-square fit quality output on the advection form's temperature
and dew point gradient plot (~monotone had previously included a distant non-site
point in the data, slightly altering the values). Also, the gradient plots'
internal resolution has been doubled, sometimes leading to slightly more accurate
- Based on further research and
testing, changes were made to the temperature and dew point advection routines.
The main effect is slight increases in the strength of advection in the stronger
- Help forms now automatically unload
when a new blue-text item is clicked, so that it is not necessary to first
click 'OK' to clear the last help item before choosing another one. This change
was implemented in both wxsim.exe (the main program) and wret.exe (the retrieval
- Minor changes and additions were
made to the help files, to accommodate the new advection option.
- A bug was corrected, which had
kept the file list box on the Cull/Append form from updating when the directory
- A few text boxes on the Entry
form were widened to accommodate the longer displayed text items, which in
some cases had been cut off before.
- The Atlanta sample data in cty.fdt
was updated with a newer version, the most significant change being a small
increase in the default urban heat island effect (for this site only).
Version 10.2 (October 21, 2005) had
the following changes relative to Version 10.1 (described below):
- The range of allowed text widths
(in both the main program and the retrieval module) was increased to accommodate
a very wide range of system conditions.
- A few blue-text help items had
ended up with the wrong links during the change from Version 9.6.5 to Version
10.0. These have now been corrected.
- Label name changes from Version
9.6.5 to Version 10.0 had caused incorrect behavior of the red versus blue
caption highlighting on the advection form. This has been corrected.
- Problems were discovered in the
Import/Cull/Append routine. This caused in some cases severe limitation of
the number of METAR or SYNOP sites culled from downloaded data. This has been
corrected. NOTE: This is an old routine, whose functionality and speed have
been greatly surpassed by similar abilities in the WXSIMATE program.
- A new document, WXSIMHELP.DOC,
has been included in the package. This conveniently displays for direct reading
all of the information in the blue-text help file help2.txt. Many thanks to
Fred van den Bosch for this idea and for organizing it into this format.
Version 10.1 (August 27, 2005) had
the following changes relative to Version 10.0 (described below):
- The location list box was widened
(country names were partially cut off in 10.0).
- UV index is now rounded off to
tenths for all sun altitudes.
- Slight cosmetic changes were made.
- It was discovered that, despite
a message to saying the program was defaulting to Atlanta, users without registration
codes were still able to access their home sites. This has been corrected,
so that the code - obtainable by paying the upgrade fee - is now required.
(The upgrade to 10.0 was a lot of work!).
- Two new items have been added
to the 'Other Data' section of the retrieval module: % Sky Cover (Lev 1, 2)
and Wind Direction. The new sky cover item compliments the existing % Total
Sky Cover item (which combines levels 1-5) by displaying the combined coverage
of just those clouds in levels 1 and 2. The wind direction item allows plotting
of wind direction at all forecast times, instead of just the few times a day
wind vector 'sticks' (which are still included).
- Updated and corrected some help
file items for the retrieval module.
Version 10.0 (August 16, 2005) had
the following changes relative to Version 9.6.5 (described below):
- The entire program (both the
main and retrieval modules) have been converted from the old 16-bit Visual
Basic 2 to 32-bit Visual Basic 6. This should give the program a long future
of compatibility with upcoming versions of Windows. Backwards compatibility
has been maintained so that old data, customizations, and forecasts can be
accessed smoothly from the new program. Also, significant speed increases
resulted, by a factor of about 1.7, so data imports and forecasts
take only about 60% as long as before.
- A new registration and custom
file access method has been implemented. This allows all users full use of
the program in demo mode (i.e. using Atlanta as a default site), while a simple
registration code (provided with registration or upgrade fee) unlocks full
use of customized sites. Also, the last site used is conveniently the default
site at next boot-up.
- The names of the executable files
have changed: wxsim.exe replaces the old wxsimw.exe, and wret.exe replaces
wxrw1.exe. This allows older versions to coexist in the same directory with
the new ones, in case you ever want to compare output or performance.
- The forecast saving routine has
been changed. Now, all forecasts are automatically saved as 'latest, and the
save is applied AFTER the forecast run (like most first time users seem to
expect). There is also a new button on the output form to allow for convenient
saving of forecasts right after a run. Furthermore, there is a warning if
you try to overwrite an existing file.
- A very carefully calibrated correction
has been made for some subtle temperature biases I discovered. Specifically,
there will be a tendency, as compared with earlier versions, for cloudy days
in summer to be warmer, cloudy days in winter to be cooler. Clear days at
all times of year should be very similar to before, with perhaps a trivially
smaller diurnal range.
- Numerous cosmetic changes, including
replacement of many 'scroll bars' with 'sliders', particularly with wind direction,
relative humidity, and cloud cover, where the tick marks are particularly
- Added wind arrow graphics to help
user visualize the entered wind direction.
- Added level 1 temperature as a
variable for the Interrupt Planner and READY input.
- Added adjustment '+' and '-' buttons
the Interrupt Planner to allow quick raising or lowering
of all values of the chosen planned (or imported) item.
- Modified the low level mixing
routine to reduce the likelihood of superadiabatic lapse rates between the
surface and level 1.
- Changed the Interrupt Planner's
saved-file retrieval form so that it now indicates only files with extension
- Improved formatting of printouts
in all modules.
- Slightly reduced the diurnal variation
of thickness and temperatures on the Interrupt Planner.
- Added three new message boxes
to warn (mainly) new users who fail to make use of FOUS, upper air, and/or
READY data, and give them a second chance to use the data if they like. Also,
provided more explanation in the 'Visibility uncertain
' message box.
- Changed the METAR pressure import
algorithm to avoid a bug which could incorrectly show a station pressure as
a surface pressure. Also changed both this and the corresponding synoptic
import routine to ensure precision to 0.1 mb (previously, round -off errors
- Changed METAR routine to allow
more reports with some missing data, such as winds. This may increase the
number of advection sites available for use.
(Note: the next 7 items are specific
to the data retrieval module, wret.exe)
- Corrected various problems associated
with use of Daylight Savings Time, including a situation in which the text
output would repeat the same day of the week as the heading.
- Enhanced the data saving routine
so that actual 24 hour and AM/PM extreme temperatures are recorded for later
retrieval with wret.exe. (The old wxrw1.exe will not properly read these new
files, but the new wret.exe can read the old ones).
- Correction of a bug which had
caused the dates to line up wrong on plots of forecasts initialized just before
midnight, and had also caused the text output to sometimes repeat the same
day of the week over and over.
- Added the WXSIM version number
(10.0) to the caption of the main form.
- Added AM lows/PM highs to the
plots (for new forecasts) and enabled use of the new data (see (2) above))
saved by wxsim.exe.
- Corrected a bug which could confuse
the program's determination of the mouse position on the plots after a printout
- Corrected a small bug in the plotting
routine which would combine all precipitation before the first day displayed
with the first day's precipitation.
Version 9.6.5 (May 21, 2005) had
the following changes relative to Version 9.6.4 (described below):
- A bug, which occasionally produced
an overflow error during import of advection data (probably only with advection
map at the closest zoom setting), has been corrected.
- A message box, instructing the
user to return to neutral advection setting before importing regioanl advection
data after a flow curvature change, has been added in a more appropriate place
Version 9.6.4 (April 23, 2005) had
the following changes relative to Version 9.6.3 (described below):
- A newly encountered format of
METAR data (with "$" signs connecting separate reports) triggered
an error in previous versions. This has been corrected, and the first METAR
report of such a string will now be read.
- Inappropriate triggering (such
as when the error discussed above occured) of a 'file not found' error message
was corrected. If future errors occur, they should now be properly identified
in such messages.
Version 9.6.3 (March 25, 2005) had
the following changes relative to Version 9.6.2 (described below):
- Error trapping and data quality
control were improved for barometric pressure entries.
- Minor information changes were
made to two forms.
Version 9.6.2 (March 21, 2005) had
the following changes relative to Version 9.6.1 (described below):
- A problem reading certain METAR
reports (in particular, Italian ones with an empty wind group "/////KT")
- An additional minor change was
made which should slightly increase the speed of the METAR and SYNOP search
Version 9.6.1 (March 20, 2005) had
the following changes relative to Version 9.6 (described below):
- A bug introduced in Version 9.6
was corrected. This bug had caused an error message when attempting to use
the Diurnal Breeze routine.
- Two types of weather descriptions
were added to the new (with Version 9.6) commas separated variable files.
Version 9.6 (March 19, 2005) had
the following changes relative to Version 9.5.1 (described below):
- A new export file type was added:
comma separated variable (.csv), which can be imported into spreadsheet programs
for users who wish to do their own types of analysis and archiving. The name
of the file (before the extension) is the same as for the .wxf and .txt files
- A few new error traps and message
boxes were added. One concerns the above-mentioned files, and prevents errors
resulting from trying to open file names which are currently in use by other
programs. Another is on the Advection form, where new message boxes help prevent
usage errors (which would not otherwise stop the program, but would degrade
the forecast) such as failing to 'Use' imported data, or failing to re-import
after curved-flow adjustments.
- Small improvements of the help
file were made.
- A couple of minor cosmetic and
informational changes were made.
Version 9.5.1 (January 26, 2005)
had the following changes relative to Version 9.5 (described below):
Version 9.5 (December 29, 2004) had
the following changes relative to Version 9.4 (described below):
- The extended advection map data,
including information for coloring water blue, was inadvertantly omitted from
at least some of the recently released packages (probably startng with Version
9.3). They are included now.
- NOAA just changed the ETA model's
name to NAM. WXSIM can now handle this, and is still able to import old ETA
data as well. All references to 'ETA' in the help files were also changed
- Small changes in the documentation
were made, including the option of paying for WXSIM or WXSIMATE via PayPal.
Version 9.4 (December 14, 2004) had
the following changes relative to Version 9.3 (described below):
- Minimum and maximum relative humidity
for each day was added to the 'Summary' output. Similarly, average relative
humidity for all complete days was added to the 'Totals'.
- Spacing between numbers was improved
in the 'AM Lows and PM Highs' output, so that the values would more dependably
line up underneath the day headings, even in the case of single digit values
(common when using Celsius in winter). The same correction was applied to
the Retrieval module.
- Minor cosmetic changes were made
to both the main module and the retrieval module.
- Minor changes were made in the
help files for both the main module and the retrieval module.
- A change was made to accomodate
'FW' (few clouds) as a sky cover type in the MOS parsing routine. (When encountered
previously, this had triggered a message which said 'Bad sky cover data. Assuming
Version 9.3 (December 10, 2004) had
the following changes relative to Version 9.2 (described below):
- The text box for the name of the
data file to be imported has now been enabled, meaning you can now type directly
into it as an alternative to selecting it from the drive, directory, and file
list boxes below. This may be faster if you save a lot of old data files which
you might have to scroll through. Also, an error trap for bad file names has
- A small bug affecting the displayed
solar and UV radiation on the Data Entry form has been fixed. This bug had
allowed imported READY data to alter to sun angle used in these displays,
though the resulting errors never appeared in forecast output.
- Several, mainly cosmetic changes
were made, including the wording and positions of the Introduction, Registration
and License forms.
- A setup/installation program called
setupwxm.exe was created (using Inno Setup), to serve as the primary mode
of distribution for this new version. A similar setup program, setupwmt.exe,
was created for distribution of WXSIMATE Version 1.4 (compiled on December
Version 9.2 (October 18, 2004) had the
following changes relative to Version 9.1 (described below):
- Changes were made to the algorithm
involving the albedo of snow cover. In particular, it was found that the previous
version overestimated albedo in cases of dry (relatively treeless) sites.
This was improved based on considerable additional study of the effect of
snow cover on both minimum and maximum temperatures. One method was climatological
studies of surface data, using upper air data to control for overall air mass
temperature, for many cities, including Peoria IL, Glasgow MT, Minneapolis
MN, Boulder CO, Flagstaff AZ, Nashville TN, and others. Another was study
of snow swaths, especially from the heavy February 1973 storm across Georgia
and the Carolinas, and also some consideration of a study of Midwestern snow
swaths by David Travis, Steve Curran, and Amy Nielsen (see ams.doc
- Changes were made to ensure compatibility
of local data import with the latest version (1.3) of WXSIMATE.
- Slight cosmetic changes were made,
including a new icon, wider text and list boxes on the Data Import form, and
a more thorough explanatory note on the Save Data form.
- An error trap was added to prevent
runs with zero barometric pressure (i.e. resulting from incomplete METAR data
Version 9.1 (July 31, 2004) had the
following changes relative to Version 9.0 (described below):
- An option to display precipitation
in bar graph form, rather than as color changes of the temperature curve,
- A bug, which could have prevented
the mapping routine from making certain sections of the ocean blue, was fixed.
- A bug which read current precipitation
rate as much higher than actual, when using local data import from home weather
stations (via WXSIMATE), was corrected.
- A more versatile format for the
files localcal.txt and localdat.txt (produced by WXSIMATE) was adopted and
allowed for in WXSIM, so as to avoid errors that occured in German language
Windows settings. This error had resulted from conflicts between periods and
commas as decimal points, and is now avoided by storing values as large integers.
- Slight cosmetic changes were made
to some forms.
Version 9.0 (July 7, 2004) had the following
changes relative to Version 8.9.1 (described below):
- Improvements were made to the
advection map backgrounds. The data now covers the entire world, and some
additional details and resolution have been added - mainly large lakes and
bays, mainly in North America. Also, bodies of water are now displayed blue
(before, all backgrounds were white).
- The program now saves the name
of the last imported data file, and displays it as the default the next time
you use the program. This can save time in selecting the file for import,
especially if you use the same name each time (though if you intend to archive
the data, this may not be the best choice).
Version 8.9.1 (January 24, 2004) had
the following changes relative to Version 8.9 (described below):
- WXSIM can now use data from a
new companion program, WXSIMATE, which can greatly speed and ease collection
of data from internet sources, and also allows import of many data types from
home weather stations (at this point only those using Davis WeatherLink 5.0
and later). WXSIM can also open WXSIMATE if the latter is present in the same
- The calibration run is now able
to use WXSIMATE data to simulate conditions leading up to the present. This
may increase forecast accuracy somewhat, especially on days when large changes
in cloud cover, wind speed, or precipitation have occured since the last 'midpoint'
of the diurnal temperature curve.
- A new 'Refinement' item has been
added: "Stop AM Rain". This addresses a problem that has existed ever since
WXSIM began using external model data several years ago. In particular, much
of the warm season rain in many areas consists of heat-induced afternoon and
evening thundershowers. The 3 or 6 hour resolution model data (NGM, ETA, or
GFS) as used by WXSIM, however, often started rain in the late morning or
early afternoon, prematurely cutting off heating and underforecasting the
high temperature. This new option lets you specify the earliest and latest
times for rain to occur. Carefully devised location and season-dependent default
times are provided, but can be overridden.
- A couple of related bugs involving
the Interrupt Planner, particularly when using READY data or clicking changes,
have been resolved. These sometimes caused parts of the data to dissapear
on subsequent runs.
- Recall of the Monotone and Best
Fit check box values, after clicking 'Use Previous' on the advection form,
may not have worked properly in some earlier versions. This has been fixed.
- The activation indicator for 'Sea
Breeze' at the bottom of the Output form now properly indicates 'Mtn/Vly Breeze'
if the mountain/valley breeze routine is in use instead of the sea breeze
- A very minor bug was discovered,
in which second and later imports of FOUS data would automatically be active
without the user authorizing it by clicking the 'Use FOUS' button. Now, any
additional FOUS imports must be freshly authorized. Also, the 'Clear' button
below the Use FOUS button now says 'Clear FOUS'.
- Several minor cosmetic changes
were made to a number of forms, including enlargement of the raw surface data
view box accessed from the Import form. Also, the 'Scanning for METAR' message
now properly says 'Scanning for MOS' that is the case.
- This is not a change in the program
itself, but note that FSU now provides the buoy data formerly available at
PSU. The new web address is here
- A bug - which prevented most buoy
data in synoptic format from being read - has been corrected. At the same
time, the ability was added to distinguish between rare cases in which a buoy
had the same identifier (synoptic code) as a land station.
- Missing data (such as dew point)
now should show as an 'M' on the advection map and the advection site list
box, instead of '0' or '999', which was the case before.
- A minor, rarely encountered bug
- in which the program failed to remember the latest choice of synoptic versus
METAR as the default surface data type - was corrected.
Version 8.9 (November 8, 2003 had the
following changes relative to Version 8.9(described below):
- The 'Search' routine on the Advection
form (button next to the anticyclonic/cyclonic flow scroll bar) has been improved.
It now more consistently finds an optimum fit to curved flow. It is not any
faster than before, and still may occasionally fail to find the absolute best
fit, but it usually does quite well. You can still adjust the curved flow
manually, as well. The help file was also updated to reflect this change.
- A bug, which caused failure to
read READY data out past about the 6th column, has been corrected. WXSIM now
reads as many columns as the READY meteogram text routine can produce (10
items, or up to 11 columns if 'wind flags' is selected).
- A wider range of text widths has
now been provided, to accommodate practically any computer, settings, and
Windows version possible.
- A change was made to avoid problems
that could occur if GFSX MOS data was present in a file along with METAR to
be imported. In particular, if the GFSX MOS site had the same identifier as
a METAR site being searched, the older version would mistake it for METAR
data, then crash with a 'Subscript Out of Range' error. This problem has been
- A typographical error in the algorithm
for ultraviolet index was corrected. This error was causing too-low UV index
for sun elevations of 15 to 30 degrees, sometimes visible in retrieved data
plots as a pair of spikes near the tail ends of the UVI curve. Theses curves
will now be much more smooth.
- When the default advection routine
('frontal codes') is chosen, new default values of the frontal code will appear.
Before the forecast run, this will be 2 ('gradual turn towards upwind normals'),
but on subsequent shifts, either manual or automatic (i.e. due to READY data)
a new value will be calculated. This will often be a higher value, suggesting
the passage of a front. The most well-defined fronts will be cold fronts indicated
by a large shift to a direction from higher latitudes.
- In the retrieval module (wxrw1.exe),
adjustments were made to the text output format to allow more details of the
'Weather' text description. Previously, the allowance of only 10 was cutting
off the extended information - such as dew, frost, and precipitation type.
Now, all data is shown, except that each of the two 10 character parts of
the weather description is cropped to 9 characters because of space limitations
- The text width range in wxrw1.exe
was also increased, partly to accomodate the longer lines of text, but also
to provide for a wide range of computer setups.
- A new 'Superimpose' button on
the plotted data form in wxrw1.exe now allows plotting of multiple forecasts
on the same graph, for comparison. There is also a new check box allowing
the user to specify whether or not subsequent plots are to use thicker lines,
to distinguish them from earlier ones.
- A minor bug that sometimes caused
omissions of convective bulletins in wxrw1.exe's text output was fixed.
- The starting time of a saved forecast
was added to the identifying information when selecting a file to view in
wxrw1.exe. Also, the text color of this identifying information was changed
from gray to black to improve readability.
Version 8.8.2 (September 5, 2003) had
the following changes relative to Version 8.8.1 (described below):
- Most of the commonly viewed forms
in both the main program (wxsimw.exe) and the retrieval module (wxrw1.exe)
were enlarged significantly, from about 640x480 to 800x600 pixels, allowing
much larger graphics and in many cases more space between controls.
- The optical effects of clouds
were altered slightly, based mainly on careful studies I did using NOAA's
SAMSON data and nearly two solid months of METAR data for KATL correlated
with measurements of solar radiation archived every 10 minutes using a Davis
Vantage Pro weather station I recently installed at Woodward Academy, where
I teach. I also did some analysis of hundreds of forecast I've logged over
the years using WXSIM, to see if days with small-medium diurnal ranges (and
therefore likely partly to mostly cloudy) had these diurnal ranges suppressed
in the forecast; they did, though the effect was slight, but corroborated
the need for at least a small change. The main effect of these changes is
a modest reduction in the default opacity of clouds (including the auto cumulus
and stratus routines as well as clicked and interrupt input and imported METAR
or synoptic data), given areal coverage, especially under partly to mostly
cloudy skies. Some of the reason for this is consideration of sunlight reflected
off the sides of clouds (the cloud gap effect), which had not been previously
taken into account. The main effect here is a small (about 1 degree C or nearly
2 degrees F) increase in diurnal range on partly to mostly cloudy days. Another
small change is that cirrus clouds now have enhanced reflectivity with lower
- While doing the studies above,
I found that clear days had very slightly too much diurnal range, by perhaps
2% (about half a degree F) on average. Slight changes were made to correct
- In conjunction with the studies
mentioned above, in (2), solar radiation (visible, in Watts per square meter)
was made an output, also saved in .wxf files for use in the retrieval module.
The solar radiation is based largely on the Davis data from my school, but
also from the SAMSON data, especially a period of actual (not modeled) measurements
from the Georgia Institute of Technology, mainly in 1981. This output takes
into account sun angle, distance from sun, haze, clouds, and elevation.
- Ultraviolet Index is now also
output, along with solar radiation, in a new output menu suite (#9). UV index
is based largely on data from the Vantage Pro station at my school, but also
from other sources, such as
conditions: UV sensitivity to atmospheric
radiation: Solar erythemal ultraviolet
I developed the models for this
and visible solar radiation largely myself, based on general theory and
empirical fitting of the (SAMSON and Davis) data, but consulted the above
sources for data and general understanding. The UV Index is, as best I can
tell, basically in units of 25 mW per square meter, global, from about 280
to 390 nm, and closely fits the output of the Davis sensor.
- The above visible and UV outputs,
along with a new total sky cover output, are now displayed on the Data Entry
form in boxes whose values change with every adjustment of relevant factors
(time, place date, clouds, haze, fog, etc.). This permits some forecasting
of these items by simply 'playing' with the Entry form's controls, before
making a forecast run. The ozone layer thickness in Dobson Units can be input
here as well. A good source of real time data for this is
Global Ozone Maps
- An extension of the 'weather'
output text was made, so that sky condition (i.e. clouds) is always displayed
(and printed, if you request a printout), even when dew, frost, fog, etc.
are output. To accommodate this, the text window on the Output form was made
wider. One small problem can result from this, however: the greater amount
of data per line of output means the text box can fill a bit sooner than before.
For example, you might find the text box filling up with just 6 days of half-hourly
data, or three days with a 15 minute interval.
- You can now turn the 'convective
bulletins on or off under 'Customize' on the menu bar. Turning it off may
help you squeeze in all the output from a long forecast if you encounter the
situation described in (7) above.
- Several related changes were made
to wxrw1.exe (the retrieval module): Solar radiation handing was greatly improved,
by using the new output from the main program and by re-calculating values
from old forecasts. UV is likewise input and can now be calculated from old
forecast data, except that the ozone layer thickness will then be assumed
as 300 Dobson Units as a default. Up to 5 items (instead of 4) from each set
of output options can now be displayed. Finally, the quality of the printouts
was improved with bolder lines and text.
- The blue-text help files have
been expanded to include the new items in the main program (wxsimw.exe), and
to further describe old ones in the retrieval module (wxrw1.exe). For example,
in wxrw1.exe you can now read descriptions or definitions of the various convective
bulletins and stability indices.
- Now up to 11 columns of READY
data can be read at once, to accommodate recent changes in the READY site.
This allows 10 items, including wind flags (which use two columns) to be imported
at once, making for - at most - two downloads to get all the data WXSIM can
use (previously as many as three might be needed to get all readable data).
- Several changes have been made
to the choices of 'Parameters' on the Entry form's menu bar. Output intervals
of 2 and 3 hours have now been added, as well as new forecast durations of
5, 7, and 8 days. Along with this, the actual iteration interval (output interval
divided by iterations per interval) is now forced to be 30 minutes or less,
to help avoid the small errors that can creep in with larger intervals. Finally,
this same 30 minute or less criterion is applied to export to .wxf files (for
use in the retrieval module), to ensure saving of sufficient data for later
analysis in that module.
- A new button on the Interrupt
Planner opens up a form allowing you to specify timing and magnitude of partial,
annular, or total solar eclipses. The eclipse will then occur automatically
during the forecast run, with resulting changes in various conditions, especially
- The Text Width item under Customize
now opens up a form with a scroll bar, allowing finer control of this item
if text alignment is ever a problem.
- The retrieval module (wxrw1.exe)
now automatically save a text file of the retreived data when you click 'View
Text'. This file is saved under the name 'lastret.txt and into the same directory
from which you retrieved the data (.wxf file). This new text file facilitates
using the output in different ways, such as on a web page. Such posting of
WXSIM output is permitted, as long as the program (WXSIM) and author (me)
are credited. If you want to save images (screen shots) of graphical output,
one way is to use ltPrtScrn and then paste into Paint or some other graphics
- Also in wxrw1.exe, the summary
of overall data (i.e. averages, extremes) is now automatically printed below
any printed plots, along with identification of the units used (which now
also appear in the Text output).
- In the main program, a bug - which
could occasionally cause the program to miss abrupt changes in planned wind
direction or precipitation - was fixed.
- On the Interrupt Planner, the
'Showers' and 'Reduce superadiabatic' check box values, along with the wind
direction tolerance, are saved for subsequent runs in the same session and
for the next boot-up. The same has now been done for the feet/meters and Fahrenheit/Celsius
buttons on the Upper Air form.
- A bug that caused the Interrupt
Planner to forget the last-clicked values for precipitation and wind, when
attempting to add more clicks (without clearing) on subsequent runs, has been
corrected. Along with this, the shower option now uses the end of the forecast
as the end of the shower period if precipitation is started but not altered
(one click only). It operates as before in the much more common case of multiple
- All six calculated stability indices
(instead of just Lifted Index, as before) are now displayed on the Upper Air
- Recent changes in the headings
of some data types on the READY site required corresponding changes in WXSIM's
routine for reading these. WXSIM should now be able to read all the same data
types as before, and still read older data as well.
- A bug on the Recent Precipitation
form, which caused the last month's precipitation to default to a value in
inches when metric units are in effect, has been corrected.
Version 8.8.1 (July 25, 2003) had
the following changes relative to Version 8.8 (described below):
- Based on careful analysis of
additional climatological/historical data, some changes were made to a routine
handling moisture exchanges between the surface and the atmosphere and the
surface (i.e. formation and evaporation of dew or frost). The main result,
in most cases will be slightly more transfer than before, and hence slightly
greater variations in dew point, mainly on clear nights and mornings.
- The 'Dew/Frost' scroll bar on
the Data Entry form now allows somewhat greater amounts than before. The definitions
of 'light', 'moderate', 'heavy', etc. have been changed slightly (i.e. what
was called 'moderate-heavy' might now be called 'moderate'), but - for the
sake of consistency - the numerical values shown will have exactly the same
effects as before.
- Two changes were made concerning
fog formation. First, the tendency to form fog was slightly reduced (in favor
of more moisture consensing out as dew or frost). Second, this 'sensitivity'
or proneness to fog formation can now be customized to the site. There may
be multiple reasons, some perhaps difficult to identify, for site-to-site
(or even time-to-time) variations in this, but such differences appear to
be real. A recommended setting will be included with customization, but the
user can now adjust it (under the 'Customize' menu item on the Data Entry
form) if experience warrants. Any new setting of this is saved on program
- Some changes were made to the
help file, in light of the above changes affecting dew, frost , and fog.
- The METAR and synoptic surface
data import routines were made more versatile, specifically to allow import
of some New Zealand data fields which the program wasn't recognizing properly.
In particular, the program now recognizes kilometers as a valid visibility
unit (previously, only statute miles and meters were recognized) in METAR
data, and now recognizes whole number temperatures and dew points in synoptic
data, in addition to the standard one-decimal place format.
- Slight changes were made to the
registration information, mainly to alert new users to check web sites for
a possible new pricing structure in the fairly near future.
Version 8.8 (July 15, 2003) had
the following changes relative to Version 8.7.2 (described below):
Version 8.7.2 (June 14, 2003) had the
following changes relative to Version 8.7.1 (described below):
- Under Start on the Entry form
there is a new option: Full Start. This combines the actions of Test for Midpoints
and Calibration Run, to save a mouse click. The earlier items are still there
and can be used as before; there are times when the midpoint times are of
intrinsic interest, or when one might want to alter the initialization time
(and corresponding data) in order to change which of the two daily midpoints
starts the calibration run (this being a somewhat 'advanced' manipulation,
- The output is now saved by default,
rather than requiring previous approval. The default file names are 'latest.wxf
and 'latest.txt, but other names can be specified in advance under the File/Save
item, where it is also possible to avoid saving data if desired.
- The choices (check boxes) of
data import types on the Import form are now 'remembered' during the run and
saved upon exit, thus saving most users a few mouse clicks each run.
- The check boxes on the FOUS form
are now checked by default, except for the shower option, which can still
be checked if desired (it is overruled by the shower check box on the Interrupt
Planner if precipitation is entered there).
- A bug has been corrected. The
problem was a bad interpolation between level 1 and 2 for finding the height
of the 925 mb level, when the surface pressure is above 925 mb, which is usually
the case for sites below about 750 meters (2500 feet) elevation. Actually,
the error was negligible with surface pressures in the range of 960-1000 mb,
but often significant above and below that. In most cases this error probably
had no effect other than the erroneous output on the upper air data form.
- Improvements were made other
interpolation algorithms for 925, 850, and 700 mb heights and temperatures,
mainly for stations at relatively high elevations.
- Heights and thicknesses are now
geopotential (as opposed to geometric), with respect to the surface. The previous
algorithms (from a few years ago) were slightly flawed due to an attempt to
make the heights geometric (geopotential is actually more the standard) and
then fit them to radiosonde data, which turned out to be geopotential. The
previous errors, relative to geopotential values, were negligible in the mid
latitudes, except possibly at 300 mb, but were marginally significant at low
and high latitudes (within perhaps 30 degrees of the equator or of the poles).
The present scheme provides very accurate geoptential values.
- A new customization parameter
was introduced in order to better fit climatological normal temperatures,
with dew points also "piggy-backed" into the scheme. The fit was already excellent
in most cases, but for some sites - especially in the western United States
- small discrepancies remained because of a more rapid cool-off in the fall
as compared to the spring warm-up. The new parameter now gives an excellent
fir for these sites as well. It is doubtful that any sites already customized
suffered more than about half a degree F error because of the earlier inadequacy
(and that mainly just in the spring or fall).
- It was found that, in the 'Other'
location option (as opposed to custom sites), entered climatological normals
would revert to default values after one run, with no warning. This has been
changed to preserve the user-entered values through multiple runs, and also
to re-prompt for new data if the date is changed while the 'Other' option
is still in effect.
- The manual was expanded to include
detailed instructions on collecting data from the Internet and examples and
explanations of such data.
- A new form, with a message for
new users, was added. Further viewings can be prevented by leaving a check
in the 'Don't show this message again' box.
- The program's starting form now
sports a graphic: a photograph taken by the author in July, 2002, from the
top of Mt. Tamalpais near San Francisco. The view shows sunset over a deck
of stratus in the the marine layer inversion over the cold waters of the Pacific.
Temperatures at the time were about 10 degrees F warmer atop the 2500 foot
mountain that at sea level! If you don't want to see the picture on startup,
or if you want to make the space (901 KB) available, you can delete it without
affecting the program.
- A bug in the retieval module
(wxrw1.exe), that labeled every day 'Monday' when retrieving data stored in
day/month/year format, was corrected.
- Provisions were made to avoid
possible problems involving the use of commas (i.e. as done in many European
countries) versus periods as the decimal point symbol. It was not clearly
established that any errors were beings produced this way, but the change
was made to help preclude the possibility.
- A problem was discovered involving
the interaction of the program with some Windows environments. In particular,
Windows 2000 under Dutch settings and Windows XP under U.S. settings, were
found in sporadic cases to misread READY wind direction data, sometimes causing
errors (Invalid Property Value, Overflow, or simply making the wind direction
north when it wasn't). A work-around was implemented (it wasn't a 'bug' in
WXSIM, per se) and the problem is now apparently corrected.
Version 8.7.1 (March 9, 2003) had
the following changes relative to Version 8.6 (described below):
- A bug that could very occasionally
read METAR data as MAPS soundings was corrected.
- In the retrieval program, saving
of settings upon exit now includes the new 850-700 mb thickness and freezing
- The precipitation type algorithm
was modified to take into account more details of the vertical temperature
profile. Numerous schemes for precipitation-type decisions were reviewed and
an effort was made to make WXSIM's decisions closer to the consensus of these
others. Results will be very similar to before, but with some rain and sleet
mixture situations now replaced by rain and snow mixtures. Also, sleet occuring
in dry surface conditions will more readily turn to rain in certain situations
as the air approaches saturation.
- Some new precipitation descriptions
were added, including distinguishing between primarily rain mixed with some
snow (RN/SNW) and primarily snow mixed with some rain (SNW/RN).
- The algorithm for determining
upper boundary layer temperatures was found to yield too-warm values in many
precipitation scenarios. This was corrected to make more likely lapse rates
in the boundary layer during precipitation.
- 850-700 mb thickness (often useful
in distinguishing between rain and snow) was added as an output on both the
Upper Air form and in the text output. It is also included when saving data,
for later recall with File/Retrieve.
- Freezing level (above both sea
level and ground level) was added as an output on both the Upper Air form
and in the text output. It is also included when saving data, for later recall
- The Retrieval module was modified
to include 850-700 mb thickness and freezing level.
- Changes and additions to the
help file were made in light of the above changes.
- The map file was augmented to
include all of South America.
Version 8.6 was (January 29, 2003)
had the following changes relative to Version 8.5 (described below):
Version 8.5 (December 27, 2002) had
the following changes relative to Version 8.4.2 (described below):
- Routines involving mixing in
the lower atmosphere were modified to allow greater surface warming than before
under certain conditions (conducive to mixing) involving warm air in levels
1 and 2. Similarly, more mixing (than before) with cool air in levels 1 and
2 is now allowed, keeping temperatures closer to WXSIM's thickness-based maximum
- Three new features were added
to the advection options. First, a best fit straight line fit was added to
the existing options. Second, data points are now plotted along with the curves
on the upwind gradient graph. Finally, a new 'distance ratio' adjustment option
was added to the Regional Data routine. Previously, data from stations varying
in upwind distance by a factor of less than 1.3:1 were averaged together.
The default is now 1.15:1, which is generally better due to the large number
of advection sites now included in most customizations, and also allows finer
resolution of changes in the slope. This factor can now be adjusted from 1:1
(no averaging) to 1.3:1 (the old value).
- New help items were added for
the above features.
- User-made changes in the Interrupt
Planner's wind direction change tolerance (default is still 40 degrees) are
now saved until (but not after) exiting the program, allowing for slightly
quicker repeat forecast runs.
- Changes were made to accommodate
the new READY meteogram text format (the old data can still be read, in case
you want to run old files). Small changes were also needed even for the supposedly
'old' format available until February 1, 2003, as there were actually some
small labeling changes even there. There is now no need to remove headings,
and mixing of model data can still be done, by simply listing the multiple
models in the same file.
- A major new addition is the ability
to read NGM, AVN, and/or ETA MOS data for advection sites, simply by selecting
the 'MOS' option and importing from the appropriate file. This is generally
not advisable at program initialization, but can be a big help later in the
forecast run if wind shifts occur. WXSIM will read the MOS files for each
site (they can be listed in any order), interpolating between 3-hourly reports
and averaging (successively weighting average so far equally with new values)
if multiple MOS products are found for the same site.
- A change was made in the reading
of '6 hour' precipitation totals in 3-hour output READY data (such as AVN
short range). I had assumed previously that the values listed in the file
were actually 6 hour totals, but I've been informed by Glenn Rolph (the site's
webmaster) that the figures are derived by subtraction of successive 3-hourly
data, so that, in effect, they are 3 hourly totals. This means that, until
now, WXSIM's precipitation totals - when derived from 3-hourly AVN data -
were only about half of what they should have been (perhaps more like 3/4
if FOUS products were used in the run as well). Now WXSIM should mirror the
AVN totals listed on READY's meteogram graphic (unless FOUS data is mixed
in). The AVN datasets are being renamed GFS, but they should be read by WXSIM
in the same way as the AVN.
Version 8.4.2 (May 31, 2002) had the
following changes relative to Version 8.4.1 (described below):
- Maps of coastlines, lakes, and
political boundaries now appear with the regional data advection routine.
Also, the number of different METAR or synoptic stations for which data is
found now appears at the bottom of the map when surface data is imported.
- The ability to zoom in and out
on the regional data advection map is now triggered by simply changing the
gradient plot scale ('+' and '-' buttons on the lower right of the frame).
Also, a new, closer scale (out to just 300 miles or 500 km) is now available.
- A new 'Search' button in the
Cyclonic/Anticyclonic flow section of the Advection form triggers an automated
search for the best fit to curved flow. It first varies the curvature to maximize
the 'percent' fit (of station wind directions to the modeled flow), then re-imports
data in case this change brings new stations into 'view'. After varying curvature
to optimize the fit again, it goes through the process one more time in an
attempt to further optimize the fit. The two additional imports do not trigger
loading of the Import form, sparing the user additional mouse-clicks.
- The help files were ammended
to explain the 'Search' feature described above.
- Message boxes now appear to advise
the user if no imported advection data exists when the Search, Use All, or
Ignore buttons are clicked.
- The Default (frontal codes) advection
routine was changed to more accurately calculate longitudes and latitudes
of upwind points. The previous routine, which had some inaccuracies in certain
directions and didn't operate well near the poles, was replaced with a great-circle
routine (new equations adapted mainly from
Ed Williams' Aviation Formulary
- Small improvements were made
in the effects ground moisture, more properly including the effects of rain
in the last month as well as the last week and last day. The changes show
up in the Estimated Max temperature (on the Upper Air form) as well as in
the forecast run, but rarely amount to more than about one degree F (0.6 degrees
C) compared to Version 8.4.2. The changes were based on new studies of 1961-1990
data from stations in the southeast U.S. as well as an ongoing verification
study in Atlanta.
- A bug which could cause an error
during 24-hour darkness or light in the arctic or antarctic was fixed. This
bug may have surfaced in recent editions, because the issue had been addressed
- A bug that sometimes caused misreporting
of AM lows was fixed. This bug occured very rarely, when certain combinations
of starting time, output interval, and iterations per interval were used.
- A bug that prevented proper updating
of the relative humidity and wet bulb entries (on the Data Entry form) upon
import of METAR data, when Celsius degrees were in use, was fixed. The bug
did not actually affect the program's output, but only the display.
- A bug which failed to adjust
imported METAR sea level pressures and altimeter readings to station altitude,
when the station pressure option was on, was fixed. There was no problem if
sea level pressure was selected, but if import was done while station pressure
was selected, significant output errors could result (at least for stations
significantly above sea level). Now the adjustment is made as needed. Incidentally,
synoptic reports were properly read anyway, since both station and sea level
pressure are routinely reported; here WXSIM simply uses the one whose option
- A decimal place was added to
the imported millibar (hectopascal) pressure diplay on the Entry form, so
that tenths are now displayed.
- Displays of vapor pressure and
mixing ratio were added to the temperature and humidity section of the Data
Entry form, and small cosmetic changes were made to the form to help the new
items fit. These new items are simply displays, and are not currently direct
inputs or outputs of the program.
- A small bug which occasionally
prevented display of the first regional data advection site on the map was
Version 8.4.1 (May 4, 2002) had the
following changes relative to Version 8.2.9 (described below):
- A bug that prevented complete
culling of synoptic and METAR files in some cases (for recent, large customizations)
- A change was made to enable import
of a certain (European, primarily?) RAOB format that had been rendered unreadable
by a recent change on FSU's interactive text web page.
- A small change to the retrieval
program (wxrw1.exe) now saves the user's choice of North American or Northwest
European stability indices upon exit.
Version 8.2.9 was completed on March
3, 2002 and had the following changes relative to Version 8.2.6 (described below):
- WXSIM can now read NGM and ETA
FOUS data from FSU's newly (May 3) reorganized web page, which presents the
data with leading spaces not present before. WXSIM can still read any format
that it could before. The new FSU page is here
- A bug, which caused an error
when modifying forecast (.wxf) files saved to a floppy disk, was corrected
in the retireval program (wxrw1.exe).
- The effect of the 'Reduce superadiabatic'
option on the planner was reduced by a bit less than 40%. Its effect is now
quite small in most cases, but it is still recommended, and is checked by
- A message box that appeared upon
attempted changes to preciptiation on the interrupt planner, when cloud cover
was insufficient, has been omitted. This change allows easy removal of READY
model-based precipitation that the user deems unrealistic.
- Precipitation now makes less
difference in solar radiation reaching the ground than before. This allows
at least light precipitation with partial sunshine.
- The high temperature routine
now assumes more random fluctuation than before with broken to overcast cloud
cover, adding about a degree F to highs in many such cases. This routine is
calibrated on the assumption that input or imported (from external model data)
cloud cover changes have a time resolution of about 3-6 hours.
- The retrieval program was modified
to use the new high temperature routine. This required use of the haze variable,
so modifications were made to both wxrw1.exe and wxsimw.exe to include this
data in .wxf files. The new wxrw1.exe can still read old .wxf files.
- A bug that caused the main program
(wxsimw.exe) to assign 12:00 AM to the previous day's date was fixed.
- The text box in the Import form
showing the number of METAR sites found was expanded to accommodate 3 digit
- In the retrieval program (wxrw1.exe),
a bug that (rarely) caused a one day shift of the date, day of week, and low
and high temperatures relative to the plots was fixed. Also, occasional displays
of these items for days with no data were eliminated.
- A few internal changes were made
in both programs: code was moved between modules in wxsimw.exe to avoid memory
problems during compiling, and some unused code in wxrw1.exe was removed to
reduce file size.
- A choice of text and graphical
output background colors (blue or gray) was added. It can be found under the
menu item 'Customize' on he Data Entry form.
- Day of the week was added to
most graphical and text output items, both in the main program and in the
- Various small cosmetic changes
were made in both the main and retieval programs, including printouts.
- A bug in the new Mountain/Valley
breeze routine was corrected (uphill and downhill had been switched).
- The user can now change diurnal
breeze base wind directions on the advection form, though this is generally
not necessary. An addition to the base wind message box now alerts the user
to this possibility.
- A feature was added enabling
customization of the amount of nighttime fluctuation in temperatures, to better
deduce minimum temperatures from the regular output. Also, the retrieval program
was modified slightly to accept this parameter from the main program.
- A new Mountain/Valley Breeze
routine was added. It and the Sea Breeze routine are now options (mutually
exclusive) under the new refinement item 'Diurnal Breeze'. New blue-text halp
features describe these options.
- Diurnal breezes (above) are allowed
to operate even with planned wind speed and direction, with the planned changes
acting on the base (no diurnal component) wind.
- Changing date or location with
sea breeze in effect now cancels the routine, so that updated water temperatures
can be verified or input before reactivating it.
Version 8.2.6 was completed on February
24, 2002 and had the following changes relative to Version 8.2.5:
- A change was made to improve
operation of the 'Reduce superadiabatic' option when FOUS data is also in
- A bug in the regional advection
routine was corrected. This started with a misnamed variable in Version 8.2.4
and caused fairly small, but sometimes significant errors in the adjustment
of data for advection sites. It tended, in general, to reduce the effectiveness
of both cold and warm air advection.
- Fairly small adjustments, motivated
by testing on both recent and historical data, were made involving the handling
of unseasonably cold air. In particular, the diurnal temperature range in
cold air masses was increased slightly, and the rate of air mass modification
(in this case, warming) was made more dependent on the depth of the cold air
mass; deeper cold air now modifies more slowly relative to shallow cold air
than before (though shallow cold air may now modify more quickly than in earlier
Version 8.2.5 was (February 18, 2002)
had the following changes relative to Version 8.2.4:
- 900 or 950 mb relative humidities
can now be imported from READY as a substitute for 925 mb, which is not available
in some models (i.e. ETA 91 km).
- A message box now appears after
READY import if multiple models were found and mixed. It also tells which
items were averaged.
- A bug, which sometimes made the
import form look for home site data when it should be seeking advection data,
was corrected. This bug had occured if multiple attempts to access the import
form were made from the advection form.
- A shower toggle interrupt item
was added. Pressing 'p' (or accessing Interrupts/Precipitation/Toggle Showers)
during the forecast run toggles the FOUS and/or Interrupt Planner shower option
on and off.
- The following changes were made
to the Retrieval program: Up to 10 days of data can be retrieved, and the
last choice of skew versus rectangular detailed sounding plots is saved on
Version 8.2.4, finalized January 20,
2002, has the following changes relative to Version 8.1 (described below):
- READY data import now allows
multiple models, such as AVN 111 km and ETA 40 km to be imported at the same
time, with any repeated items being averaged. The data must have the same
time interval (i.e. 3 hours).
- 1000 mb winds (i.e. from the
MRF model) may now be imported from READY. The wind speed is adjusted to make
it more representative of 10 meter winds.
- READY relative humidities are
now used to determine clouds even without Total Cloud Cover being imported.
- Optionally (using a check box
on the Interrupt Planner), 850 mb temperatures on the planner can be partially
overridden in the case of super-adiabatic lapse rates. This allows WXSIM more
'say' in surface temperatures when external model data is producing 850 mb
(or 700 mb for sites above 2500 feet) temperatures that would otherwise drive
- Four new help topics were added
to the Interrupt Planner form.
- Three bugs were fixed: part of
a low level mixing routine was found to be time-interval dependent, and was
made independent of it. An error that occured if location was switched while
Sea Breeze was active was fixed, by deactivating Sea Breeze upon location
change. Also, an error that occured if Snow Cover was activated - but no snow
entered - was fixed.
- Under rare circumstances, earlier
versions could have an Invalid Property Value error during the calibration
run if heavy precipitation was entered on the Recent Precip form, ending some
time shortly after the last midpoint. This has been corrected.
- All data import check boxes other
than surface data are now disabled when accessing the Import form from the
Advection form. This prevents certain errors that could occur if model or
upper air data were brought in at this (late) point. These items should be
entered before the calibration run.
- Changes have been made in the
handling of snow, specifically: the albedo algorithm has been changed to include
the effects of dark ground cover (part of the customization), the rate of
compression/settling of deep snow has been increased, effective insultation
from the ground has been made a function of snow/water ratio (fluffy snow
insulates better), the melting rate has been made more dependent on ground
temperature (especially via the 'last 4 days' user input), and freezing rain
now accumulates at a much reduced rate on top of snow, greatly decreasing
the average snow/water ratio of the snow/ice pack.
- Some display-related bugs involving
the fog, haze, and current precipitation inputs have been fixed: using 'Repeat'
now completely reverts these and the visibility to the previously entered
values and the visibility now properly reverts to 50 miles if fog is set back
to zero with no other visibility restrictions (it was getting stuck at 40).
- A message box now warns of certain
READY import problems (resulting mainly from inappropriate spaces in the data)
instead of the program locking up while trying to read it.
- Internal changes were made to
reduce memory requirements. A beneficial side effect is that the water temperature
used with the sea breeze routine now updates readily with date or location
changes (it used to require turning off and back on to erase the old temperature).
- The ability to model curved (cyclonic
or anticyclonic) flow has been added to the Regional Data advection routine.
The goodness of the fit to winds at upwind sites is reported so that the user
can adjust the flow to more closely match that indicated by surface reports.
- A text file of program output
is automatically generated and saved whenever a forecast (as a .wxf file)
is saved. The full forecast is saved (no '60 hour' option anymore).
- To allow the user to better characterize
soil moisture, the 'recent Precip' form has been modified to allow input of
the rainfall in the last month (in addition to the last 24 hours and the last
week, as was already provided). The effect is that greater extremes of soil
moisture (i.e. very dry with resulting large diurnal temperature range and
tendency toward lower dew points) can be modeled. Also, small changes in the
soil moisture description output were made to take into account to some extent
the site's normal annual precipitation; for instance, 'very dry' for a usually
moist site might be only 'fairly dry' for a normally dry location.
- A subtle but in some cases significant
change was made to an air mass modification rate parameter. In particular,
it was found (using mainly 25 years of hourly data for Atlanta, Georgia and
Peoria, Illinois) that WXSIM was tending to modify air masses (warm up cold
spells and cool off warm spells) too quickly, mainly in the fall and the spring.
The existing error was smaller in summer and very small in winter, so the
applied correction is seasonally and somewhat site-dependent.
- Small changes were made to the
routines for estimating maximum and minimum temperatures based on the modeled
temperature output. The main change involves low temperatures in clear conditions
with light winds. A study of minimum temperatures relative to lowest reported
hourly values and to temperatures at the usually coldest hour (i.e. 7 AM in
many cases) showed that most stations have short term (in between hours) fluctuations
of about 1 degree Fahrenheit in such cases - more than what WXSIM had previously
assumed. Also, it was found that winter clear day fluctuations near the time
of afternoon maximum temperature are a bit smaller than previously assumed.
The changes were made to best model the latest data.
- A very slight increase in downward
infrared radiation was incorporated, mainly to offset some the the effects
of the changes described above, but it might also be considered to represent
a small amount of 'global warming'. The change is only a few tenths of a degree
- The dimensioning of several arrays
associated with advection was increased so that WXSIM can now handle up to
48 (previously 28) upwind sites near a particular direction and a total of
300 (previously 175) overall advection sites. This allows room for the extra
sites that may 'come into view' when using the new curved flow option and
also allows for somewhat larger advection site databases in future customizations.
- The dimensioning of some arrays
associated with the Interrupt Planner and READY meteogram import was increased
so that 35 (previously 25) data points can handled for each variable. This
allows import of the full 84 hours of 3-hourly 40 km ETA data now avalable
on the READY site (only 60 were available until recently). This change also
allows more manual clicks on the Planner.
- A METAR import bug was found:
WXSIM to misinterpret a certain field of digits mixed with slashes as a temperature
and a dew point. This seems to be rare and present only in certain European
METARS, but the bug is now corrected.
- The U.S. National Weather Service
recently released a new wind chill algorithm for official use. It is generally
more 'conservative' (not as cold) as the old one. WXSIM now uses this new
- The changes in WXSIM's extreme
temperatures and wind chill are also now incorporated into the Data Retieval
module. To enable the new low temperature algorithm in the retrieval program,
a slight change was made in the format of the saved .wxf files (they now include
a temperature inversion parameter). The new program can still read the older
formats, as well as the new one.
Version 8.1 (July 3, 2001), had
the following changes relative to Version 7.3 (described below):
Version 7.3, finalized April 12, 2001,
includes one change from Version 7.2.9, in response to a small change in the format
of READY meteogram data: the year is now four digits instead of two. Version 7.3
properly reads the new format as well as the older ones.
- The algorithm for finding lifted
and Showalter indices was improved. The new values are generally a bit more
negative than before, the difference being close to 3 for LI and 1 or 2 for
- Adjustments to the convective
outlooks were made, based partly on the above changes and also some re-weighting
of the indices for the Northwest European outlooks (Boyden and KO were given
- A new feature was added to the
upper air sounding graphs on both the main program (wxsimw.exe) and the retrieval
module (wxrw1.exe): lifted parcel traces from the surface (yellow) and level
2 (green). These include both dry and saturated adiabatic effects and provide
a visualization of stability. The temperature and dew point lines were also
made more bold for easier viewing.
- The slant of the skew-T graph
in wxrw1.exe was made more standard.
- A new (fifth) advection option,
which allows direct clicking of upwind temperature and dew point profiles
onto the graph.
- A new 'Ignore' button, allowing
the user to weed out suspect data by highlighting the site in the regional
data list box and clicking the button, which also executes the 'Use All' function
- Level 1 and level 4 clouds are
now phased out of READY data (unless you click them back in) on the Interrupt
Planner, to allow more accurate overall cloud cover based on the model data
in levels 2, 3, and 5. A similar effect is now also available for NGM and
ETA FOUS, by checking the appropriate box on the FOUS usage setup form.
- The Interrupt Planner's Shower
option now produces rain of 5 times the intensity for 1/5 of the time (instead
of 3 times, 1/3 of the time), to allow more accurate overall cloud cover in
shower situations. A bug which caused excessive rainfall when this was combined
with FOUS data was also corrected.
- Handling of upper air temperatures,
when using 850 mb temperature and 1000-500 mb thickness on the Interrupt Planner,
was improved. (Previously it had sometimes concentrated the adjustments too
much in level 4; level 3 now adjusts as well to produce a smoother sounding
- A new output menu option (#7)
has been added, including sea level pressure and three new stability index
outputs: K, Total Totals, and Showalter (which was also added to the RAOB
- Convective bulletins, giving a
text description of the likelihood of showers and thunderstorms, including
their likely severity, have been added to the text output. These appear as
- Import of 850 mb (700 mb for sites
above 2500 feet) relative humidity from the READY site is now supported. This
helps with the new stability indices (above).
- The 850 mb (700 mb for sites above
2500 feet) relative humidity data and/or (depending on which options are in
use) FOUS humidities are now used in determining the level 2 dew point. This
may have small effects on surface temeprature and dew point, especially in
- Improvements were made in the
FOUS-based cloud algorithm.
- A shower option was added to the
FOUS setup form, and interaction between FOUS and READY precipitation routines
was improved to produce precipitation amounts near the average of the two
when both are in use, even with the READY shower routine in effect.
- Two bugs were corrected: Variable
wind directions in synoptic reports are now imported properly. Also, there
had been an incorrect message stating that data (FOUS, RAOB, or READY) was
over 24 hours old in the case of 00Z data from the first day of a month used
in the evening of the last day of the previous month (and this only for west
longitude time zones). This bug was corrected as well.
- There were more adaptations to
changing READY data formats (see below).
Version 7.2.9 (April 3, 2001) included
three changes from Version 7.2.8:
Version 7.2.8 (finalized March 17, 2001)
corrected a problem which allowed the duration of READY data to interfere with
that of FOUS data. Version 7.2.7 (March 17, 2001) allowed for import of new, slightly
differently formatted (in the date/time section - already corrected in version
7.2.6 - and now also in the forecast hour line) READY meteogram data, though it
can still import the older formats, too. Version 7.2.5 (January 25, 2001) added
the option of dots as date separators, as used in some parts of Europe. Also,
an oversight, which had allowed the chosen time interval to influence the effect
of the (optional) Recent Temperatures/Last 4 Days input, was corrected. Version
7.2.3 (January 11, 2001) corrected a rarely encountered division by zero error
that happened when importing READY meteogram data if the V component of wind was
exactly 0.00. Version 7.2.2 (January 9, 2001) improved handling of the effect
of nearby moderate-sized bodies of water for certain sites. Version 7.2.1 (December
31, 2000) corrected a minor RAOB import bug in Version 7.2 that had caused erroneous
1000 mb heights when that height was below sea level.
- An inappropriate 'stop' command
that was executed when retrieving saved interrupt planner files was omitted.
- Two changes were made to permit
use in Italian (and perhaps some other) regional Windows settings: dot (in
addition to colon) time separators are now allowed, and some default text
box content that caused a crash - due to conflict involving decimal points
versus commas - was changed to avoid such problems.
- A new parameter was added to help
model large seasonal changes in vegetation effects for future customizations.
(This has no effect on previous customizations.)
Version 7.2, finalized December
27, 2000, contained significant new features and changes:
Version 7.1.3, finalized November 5,
2000, contained the following changes from 7.1:
- An option was added to import
a variety a model (especially AVN and ETA) meteogram data from NOAA's READY
site and place it on the Interrupt Planner for possible use in the program.
This is especially significant because it now allows import and use of model
data (mainly AVN) worldwide (not just North America).
- Handling of advection over upwind
mountains was improved by taking into account the effects of condensation
on the windward side, which may reduce dew point and raise temperature.
- 850 mb (or 700 mb for sites above
2500 feet) temperature was added to the Interrupt Planner, and its scale adjusts
along with 1000-500 mb thickness's scale (see #1 below).
- Several minor adjustments and
additions were made, involving higher altitude sites. These include better
reading of RAOB and SYNOP data, and and adjustment to the interrupt planner's
thickness' diurnal range.
- ETA and NGM FOUS data can now
be averaged in with data (including that from the READY site) on the Interrupt
Planner, and because of this, no planner items are disabled.
- Preciptation on the Interrupt
Planner can now be specified to occur in showers, of 3 times the intensity
and 1/3 the duration of the continuous rain otherwise planned.
- Small changes were made to avoid
errors due to certain non-U.S. Windows settings. These include recognition
during boot-up of year-first date formats and a font and command change in
the on-file site list box.
- The option of different scales
for 1000-500 mb thickness on the Interrupt Planner was added.
- A bug - which improperly intialized
the interrupt planner's thickness after advection data import with FOUS having
also been imported - was corrected.
- Import of yet another variation
on TTAA RAOB data was enabled.
- A bug which had allowed the 'Start
Fresh' option to shut down the program was corrected.
- Rewording was done to permit free
distribution of this manual.
Version 7.1.2 was finalized on September
16, 2000, enabling use of another format of TTAA data, in which all lines after
the first are indented. Also, a bug which caused inaccurate initialization of
1000-500 mb thickness on the interrupt planner (only when FOUS and advection
METAR were both imported) was corrected.
Version 7.1.1 was finalized on September
11, 2000, correcting a bug that caused the program to shut down when using the
'Start Fresh' option. The only changes from 7.0 to 7.1 were two bug corrections:
a problem with RAOB import when using French Regional Windows settings was corrected,
and a text alignment problem when using a certain graphics mode was corrected
by expanding the text width options.
Version 7.0 was finalized on August
18, 2000, and included the following improvements over Version 6.4:
Version 6.4 was finalized on February
19, 2000, and included the following improvements over Version 6.0:
- A form with a clickable graph
for planning changes in cloud cover, wind, pressure, precipitation, and thickness
was added, greatly reducing the need for interrupting the program as it runs.
This includes the ability to save plans to file for later use.
- Some improvements in the 'Other'
(not on file) site routine, though customization remains essential for accurate
- Various minor changes, such as
wording, certain default choices, and the addition of sea level pressure (as
preferred over altimeter setting) in METAR import.
- Revisions and improvements to
the retrieval program (WXRW1.EXE), including minor bug corrections, the addition
of a comments section, and saving of settings on exit.
- The ability to import synoptic
data (in addition to METAR) was added.
- A new upper air adjustment button
(called '1-Click') was added. This automatically determines how recent the
RAOB and/or ETA/NGM FOUS data is and adjusts WXSIM's upper air profile accordingly
- including a diurnal adjustment for RAOB data.
- The FOUS and RAOB buttons, as
well as the new '1-Click' button described above, now adjust level 1 and 2
dew points as well as temperatures.
- The 'Use Previous' functions on
the Upper Air and Advection forms were modified to make them complete in recalling
all previous data, whereas before, a small amount of information had been
lost (namely, the 'fixed' dew points for upper air, and the 'monotone' option
- ETA or NGM FOUS data is now recognized
at times other than 00Z or 12Z (as ETA has recently begun generating output
at 06Z and 18Z as well) and is mixed with any older data appropriately (including
a new default ETA/NGM weighting factor).
- The standard of using commas for
decimal points (in certain European countries) is now supported, if Windows
is set accordingly.
Version 6.0 included several advancements
made since the release of V5.4 about a year ago, as follows:
- The ability to use NGM and ETA
FOUS data for relative humidity (to model changes in cloud cover), wind, and
precipitation was added.
- Synchronization between ETA and
NGM FOUS data 12 hours apart is now more properly done.
- The program now uses a mean boundary
layer wind direction estimate in combination with the actual surface wind
for advection and other purposes. (This is usually different from before by
less than 15 degrees).
- The advection site data plotting
routine includes an output consisting of a weighted average wind velocity
for the advection sites along with the home site, to give a better picture
of the overall wind flow and permit appropriate adjustments to wind direction
- The effect of snow cover on temperature
was studied in greater depth than before, using 25 years of data for Peoria,
IL and Nashville, TN, and eight years of data for Flagstaff, AZ. In light
of this new data, the cooling effect was reduced by about 20-30% relative
- The effect of recent rainfall
on subsequent diurnal temperature ranges was studied in greater detail than
before, using 20 years of data for Atlanta, GA. As a result, improvements
were made in WXSIM's algorithms, including correction of a minor bug.
- The above results were also incorporated
into the low-level-thickness derived Estimated Maximum Temperature.
- Descriptive terms for precipitation
intensity were brought into close agreement with those outlined in the Federal
Meteorological Handbook #1.
- The visibility algorithm was modified
in light of further research, particularly regarding restrictions due to various
types and intensities of of precipitation. In addition, a message box was
added to warn the user when the visibility reported in a METAR for the home
site is 10SM or 9999, which are often defaults used (such as with automated
observing equipment) when the visibility is actually greater.
- Estimated Maximum Temperature
and Visibility were added as output variables, in output menu formats 2 and
- An option called '~Monotone' (approximately
monotone) was added to the smooth curve advection data fit. If checked (as
it - in effect - was in version 6.0), a very distant data point with climatological
normals is included, causing the upwind gradient curves to be either constantly
increasing or constantly decreasing in most cases. If not checked, advection
may change sign from warm to cold (i.e. a cold frontal passage preceded by
warming) or vice versa.
- A couple of minor bugs were fixed.
Between Version 4.0 and 5.4, a MAJOR data collection and program calibration effort
was undertaken. This involved many years' (up to 30 in one case) worth of hourly
surface data from several stations, correlated with upper air data using a program
written especially for this purpose. (The data sources were the National Climatic
Data Center's SAMSON CDROM and North American Upper Air Data 1946-1996 CDROM.
I wrote the extraction and analysis program).
- Upwind advection sites and (if
data was imported) simple station model plots for these sites are now plotted
to help you visualize the sources of the advection data.
- There is now an option for smooth,
least-squares regression fits for advection data, regardless of the number
of sites chosen.
- There is now an option to select
and use all imported METAR and buoy data with a single mouse-click.
- Certain types of ocean buoy data
(namely, the format used on Penn State's web page) can now be imported and
- A new 'status' bar at the bottom
of the data output form keeps the user informed as to whether or not various
features (i.e. advection, FOUS, sea breeze, auto cumulus, etc.) are currently
V5.4 included many improvements made since the release of V4.0 about two years
ago, as follows:
- A new low-level-thickness-based
maximum temperature routine
- Additions to the help files and
the user's guide
- Improved handling of slowing of
cold air advection by mountains
- Maximum daily temperatures at
high latitudes in winter, especially with snow cover, were found to be occuring
too early in the afternoon. This has been corrected to fit recent data analysis.
- Increased versatility has been
added to the customization process to better fit the diurnal temperature curve
for arid sites and to better model diurnal wind variations at specific sites.
- The data import feature has been
modified slightly to eliminate confusion between METAR and other types of
data having station ID in the same field.
- More thorough screening is now
available for 'weeding out' in-between-hours METAR reports if desired.
- A bug that sometimes inappropriately
deactivated the low stratus routine was corrected, and associated default
upper level dew point routines were refined slightly.
- Improved upper air temperature
- Improved initialization of boundary
- Ability to re-generate advection
data and upper air adjustments from previous run
- Quick new method of driving initial
upper air temperatures towards FOUS or RAOB values
- Ability to read RUC-2 analysis
- Ability to cull through large
files to extract relevant data and create smaller, more appropriate files
- Much improved ability to import
data from web pages with no copying or pasting needed.