Forecast Laboratory 2015
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Practice your forecasting skills with Forecast Laboratory 2015!  It tests your ability to forecast weather severe storms will occur later in the day.  It contains thousands of charts for 450 spring and early summer days from 2010 to 2014 -- including big outbreaks, ordinary scenarios, and null events.  It is an upgraded version of our 2006 release and includes numerous SPC charts, hourly radar, and much more.

Forecast Laboratory operates in one of three modes: case study mode, chase mode, and site mode.  Here's the difference.  Case Study mode is strictly for browsing the charts without the gameplay.  Chase mode tests your ability to select a target location, and is the equivalent of doing storm chase forecasting.  Site mode considers only a single fixed location on the map, and tests your ability to anticipate whether severe weather will occur there, simulating forecast operations at a single airfield or city.

A sample of the outbreaks included
As this covers spring 2010 through spring 2014, this simulation includes:
* The April 22, 2010 Kansas tornado outbreak
* The April 30, 2010 high risk day in Arkansas, with tornadoes in the Boston Mountains
* The May 10, 2010 Norman, OK tornado
* The May 19, 2010 high risk day in Oklahoma
* The May 22, 2011 Joplin, MO F5 tornado
* The April 3, 2012 Dallas-Fort Worth tornado, bringing tornadoes to Arlington and DFW Airport
* The April 14, 2012 high risk day in Kansas, one supercell spawning a long-tracked tornado near Wichita
* The May 15, 2013 North Texas outbreak of 15 tornadoes, with one damaging cluster near Granbury
* The May 20, 2013 Moore, OK tornado, which brought yet another year of devastation to the city
* The May 31, 2013 El Reno, OK tornado, the widest on record, which claimed 4 storm chasers
* The April 27, 2014 high risk day for Arkansas and the Mayflower, AR tornado
* The June 4, 2014 high risk day in Kansas
* ... and hundreds of other storm days.

When these dates are sneaked into your forecast lineup, will you forecast them correctly?  Only with Forecast Laboratory 2015 will you know the answer.

Special notes

* There are two surface charts provided on each day: one for the southern plains and one for the northern plains.  The forecaster may use either or both of these charts as needed.

* The forecast always terminates at 0200 UTC (around 9 pm) and the day is scored.  This means that nighttime tornadoes (such as the Greensburg tornado) will not be counted in the game score.  It is assumed that you cease chasing at dusk for safety reasons.

Case study mode

If you choose case study mode, the program will not function as a game.  You will be able to review all of the spring cases between 2010 and 2014 at your leisure.  You may also continue past 0200 UTC for the Summary panel to see nighttime activity, as the tornado/hail/wind plots will work 24 hours a day.  However to keep the size of the data package under 4 GB the other products will be unavailable.

Chase mode

When you start, a random day appears on your screen.  You are presented with the full spectrum of 1200 UTC (morning) charts, including mesoscale surface maps, soundings, NCEP upper air plots, radar, and satellite imagery.  You can send them to your printer to do a hand analysis.

After you’ve perused the charts, you need to pick a base city for your chasemobile from one of 12 major cities.  Then start it on its way towards the target!

When you’re ready, advance hour by hour and watch all the charts change.  Your target might shift.  Don’t forget to adjust the position of the chasemobile!  It can be a tricky decision, because you can’t move it more than 50 miles each hour.

As severe weather unfolds, you’ll see reports stream in from locations close to your chasemobile.  A karma rating keeps track of how good or disappointing your chase is doing, comparing your own success and what’s going on just over the horizon.

At 0100 UTC (8 pm CDT) the game ends and your chase is scored.  How did you do?  Fortunately, you can try again!  There are 487 scenarios left for you to try.

Site mode

When you start, a random day appears on your screen.  You are presented with the full spectrum of 1200 UTC (morning) charts, including mesoscale surface maps, soundings, NCEP upper air plots, radar, and satellite imagery.  You can send them to your printer to do a hand analysis.

One of the first things you need to do is pick a forecast location.  This can be a simulated city, airfield, or home location.  Your job will be to issue either a watch or a warning for either tornadoes or severe weather (large hail and high wind).  Be aware that you can only issue ONE watch and ONE warning each day.  You can't cancel it later.  Also it will be valid through the remainder of the day.  Here are the differences:

* Watch.  A watch is usually issued about 2 to 3 hours in advance of severe weather (i.e. 2 to 3 hours of leadtime).  It is great to have even more leadtime than this, as your leadtime will be scored.  But don't get too confident because if you issue them too early before you've really had a chance to see the pattern, you will likely cry wolf one too many times and it will show in your false alarm ratio (FAR) numbers.

* Warning.  A warning is usually issued about 15 to 30 minutes in advance of severe weather and has very high confidence that the condition will occur.  You will not be scored on leadtime, and since high-resolution radar is not provided, you may issue them whenever you are confident of severe weather.  However you need to be quite sure the weather condition will occur.  A high false alarm rate (FAR) will send you to the unemployment line!  It should be said, however, that this dataset offers limited ability to discriminate between nontornado and tornadic supercells, so for most users it may be advisable to issue only severe warnings and ignore the tornado warning score statistics.  Tornadoes are counted as verifying a severe warning.

If you run multiple simulations, Forecast Laboratory will keep track of your skill statistics.  You may access these under Forecast > Show Score.  These scores are kept until Forecast Laboratory is closed.

The products
	Although we have strived to offer a large number of products, data for certain hours is omitted from this package to conserve space.  For example, satellite images are only available at 1500, 1800, 2100, and 000 UTC, and the SPC upper air products (except 925 mb) are only available at 1200 and 1800 UTC.

Forecast -- This panel is used in the game modes for moving your chase vehicle and monitoring reports of severe weather up until the current hour.  Red triangles indicate a tornado report, green triangles indicate a large hail report (1 inch or larger), and blue squares indicate a high wind report (50 kt or more).  Faded icons present a summary of all severe weather reported today before the current hour.

Surface data -- The surface mesoanalysis charts are provided every hour, generated from the METAR data feed that day.  There are two charts provided for your convenience, a north and a south chart, covering different areas of the Plains.  Isobars are not included so that you can practice analyzing for highs, lows, and boundaries.  You are encouraged to print charts when possible and analyze them in detail.  Around each station plot, you find temperature (°F) at the top left, visibility in statute miles and weather at center left (if significant), dewpoint (°F) at lower left, altimeter setting (units, tenths, hundredths place of inches of mercury) at the top right, wind gust (if present) in knots at center right, and ceiling (if present) at lower right signified by C and thousands and hundreds of feet AGL.  A ceiling is the lowest cloud layer covering more than half the sky.  The shading at the center of the plot shows total sky coverage.  The coloring tells you how bad the visibility and ceiling are: red means IFR (instrument flight rules, i.e. poor visibility or low ceiling) and blue means MVFR (marginal visual flight rules, i.e. a marginal ceiling or marginal visibility).  A square plot indicates an automated station.  The wind shaft faces into the wind, with long feathers indicating 10 kt and short ones 5 kt.

Radar mosaic (hourly) -- This product is a mosaic of all national radar sites, showing composite reflectivity (echoes at all levels).  This should be used to look for convective systems and check for initiation, not to assess individual storms for tornado or severe weather potential. 

Sat (vis) (every 3 hours) -- This shows a high-resolution visible image of the Great Plains.  The 1200 UTC image is not provided since the Great Plains are normally dark at that time.

NCEP 200/300/500/700/850 (1200Z only) -- These are official upper-air plots produced by NCEP (National Centers for Environmental Prediction) in the DIFAX format, which has been in use for nearly 50 years.  The advantage of this chart is that it uses all available sources, including SATOB and AIREP reports, so it is frequently much more valuable than typical upper air charts found on the Internet.  Also this chart contains observed data that include radiosonde plots, however the height/wind/temperature contours are plotted with first-guess model data.  Note that the dashed lines on the 500 mb NCEP chart are isotherms, not vorticity lines (see the SPC chart for vorticity).

SPC 300/500/700/850/925 (1200Z and 1800Z only, 925 mb is hourly) -- These are similar to the NCEP upper air charts except that they do not consist of observed data but rather are generated with hourly plots from high resolution aviation models such as the RUC and Rapid Refresh.  The 500 mb SPC chart offers absolute vorticity (field of dashed lines), which is useful for finding short wave troughs.

Soundings -- In this window you can look over soundings for 18 stations across the Great Plains.  Change the station by using the dropdown box at the bottom of the screen ("Sounding station").  Forecast Laboratory also includes 1800 UTC special soundings, if available, and much like in real-world forecasting operations you will not know whether a station will be producing a special sounding.  On a moderate or high-risk day there is about a 25% possibility a station of interest will have a special sounding.  At 1800 UTC onward, look at the time stamp at the top; if it says 18Z it is a special sounding observed at 1800Z.  The 0000 UTC soundings are not provided to conserve space and because most of your targeting will have be completed by the time these soundings are available.

SFC div/vort -- This is an SPC graphic showing divergence/convergence and vorticity of the surface wind field, as obtained from a blend of observed data and model data.  Convergence, which is the most favorable ingredient for severe weather, is delineated by red solid lines.  Divergence, the opposite of convergence, is outlined by blue dashed lines.  Isolated supercells strongly favor circular, slowly-moving convergence centers, while linear convergence axes are associated with squall lines (especially if a large temperature gradient exists, like along a front).  Cyclonic relative vorticity (reddish shading) helps show where mesolows and synoptic lows may exist, and they may be co-located with convergence centers.

MLCAPE/CINH -- This SPC graphic shows mixed-layer instability (MLCAPE) in j/kg (red shading) and convective inhibition (bluish shading).  Be aware that this data originates from high-resolution models and not directly from observed data.

Pressure change -- This is an SPC graphic that shows 2-hour surface pressure change in millibars per 2 hours.  Dashed blue lines indicate pressure falls.

SRH (0-1 km) -- This is an SPC graphic showing storm-relative helicity in the 0-1 km AGL layer, the most sensitive layer for tornado prediction.

SPC summary (every 3 hours) -- If playing the simulation and "Allow Help From SPC" is checked, you can access the SPC summary to see what the current thinking is at SPC.  The Day 1 risk area will be plotted, any watches in effect will be plotted as boxes, and warnings from local NWS offices will be shown using colored shading.  Blue is used for severe warnings and red for tornado warnings.  There is also a radar composite.

Changes in the 2015 version
* Five years of coverage, 2010-2014.
* Larger maps have been regenerated from scratch for today's bigger screens.
* Sophisticated scoring algorithm for Site Mode.
* Numerous SPC products have been added.