Isolated thunderstorms developed over the region producing some small hail. Some one inch hail was reported with the stronger storms.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS LSX wrote it up.
Isolated thunderstorms developed over the region producing some small hail. Some one inch hail was reported with the stronger storms.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS St. Louis, MO wrote its last area forecast discussion before the first event at Dec 12, 6:11 PM CST, 19 minutes earlier.
AREA FORECAST DISCUSSION...UPDATED AVIATION NATIONAL WEATHER SERVICE ST LOUIS MO 611 PM CST SAT DEC 12 2009 .DISCUSSION... /408 PM CST SAT DEC 12 2009/ SHORT TERM (TONIGHT THROUGH MON)...-SHRA WITH OCCASIONAL SLEET HAVE DVLPD ACROSS MO/IL THIS AFTN IN WAA REGIME AHEAD OF FAST MOVING SHORTWAVE TROF LOCATED OVER WRN KS AT 19Z PER WATER VAPOR IMAGERY AND REGIONAL PROFILER/VWP OBS. THIS TROF WILL MOVE QUICKLY ACROSS THE REGION TONIGHT. MORNING RAOBS AND BUFR SOUNDINGS SHOW TEMPS REMAIN ABOVE FREEZING THROUGH A DEEP ENOUGH LAYER THAT PRECIP SHOULD CONTINUE TO FALL PRIMARILY AS RAIN. THIS SHORTWAVE WILL PUSH A WEAK CDFNT INTO NRN MO TOMORROW WHERE IT IS EXPECTED TO STALL. NEXT WX MAKER FOR THE BISTATE REGION IS A SHORTWAVE TROF LOCATED OFF THE NRN CA COAST PER 19Z WATER VAPOR IMAGERY. THIS FEATURE IS FCST TO MOVE ONSHORE AND CROSS THE ROCKIES ON SUN NIGHT WITH ASSOCIATED SFC LOW DEEPENING OVER THE PLAINS BEFORE MOVING NEWD ON MON. THERE IS SOME MODEL DISAGREEMENT ON SFC LOW PLACEMENT BY 12Z MON WITH SREF/GEM DEPICTING THE CIRCULATION CENTER OVER THE IL/IA BORDER WHILE NAM/LOCAL WRF/ECMWF/GFS PLACE THE SFC LOW OVER NWRN MO. STALLED BDRY IS EXPECTED TO MOVE N AS A WMFNT BEFORE THIS LOW DRAGS AN ARCTIC CDFNT THROUGH THE BISTATE REGION LATE MON AFTN THROUGH EARLY TUE. WITH LTL MOISTURE AND LIMITED ASCENT...MODEL DISAGREEMENT ON SFC LOW PLACEMENT PRIMARILY AFFECTS FROPA TIMING AND ASSOCIATED WIND SHIFT. TEMPS WILL REMAIN NEARLY STEADY ON SUN NIGHT DUE TO WAA BEFORE FALLING RAPIDLY AFTER FROPA ON MON. SFC HIGH WILL BUILD IN TO THE REGION BEHIND THE FRONT ON TUE. EXTENDED (TUE THROUGH SAT)...EXTENDED PD BEGINS WITH SFC HIGH SLIDING SEWD FM THE NRN PLAINS BEHIND AFOREMENTIONED ARCTIC CDFNT...THUS MAINTAINED BELOW NORMAL TEMPERATURES FOR TUE-WED FOLLOWED BY A MODERATING TREND. BY WED...UL PATTN WILL TRANSITION TO A TROF OVER THE ERN US AND A RIDGE OVER THE WRN US...PLACING THE CWA UNDER NW FLOW ALOFT. ECMWF/GFS SHOW A FEW SHORTWAVE TROF PASSAGES FARTHER N DURING THIS PD. KEPT THE EXTENDED PD DRY GIVEN THE DIFFICULTY MODELS HAVE WITH TIMING SHORTWAVE TROFS IN NW FLOW ALOFT AND THAT THESE FEATURES APPEAR TO STAY N OF THE AREA. KANOFSKY && .AVIATION... /546 PM CST SAT DEC 12 2009/ FOR THE 00Z TAFS... PRIMARY CONCERN FOR AVIATORS TONIGHT WILL BE IFR CIGS OVERSPREADING THE AREA BY MIDNIGHT. CIGS AS LOW AS 500FT ARE ALREADY BEING REPORTED OVER SOUTHWEST MO...AND THESE LOW CLOUDS WILL BE MOVING UP OVER THE AREA THROUGH THE EVENING HOURS. IFR CIGS ARE LIKELY OVER THE AREA BY MIDNIGHT...AND CONDITIONS COULD DROP TO LIFR BEFORE SUNRISE SUNDAY MORNING. GFS GUIDANCE IS FAR TOO OPTIMISTIC FOR IMPROVEMENT ON SUNDAY...AND I THINK WELL STAY PRETTY LOW THROUGH THE MORNING. TERMINAL FORECASTS BRING CIGS UP ABOVE 10000FT DURING THE AFTERNOON...BUT EVEN THIS MIGHT BE TOO OPTIMISTIC AND WILL REEVALUATE SUNDAYS CEILING FORECAST FOR THE 06Z TAF UPDATE. ELSEWHERE AND OTHERWISE...SCATTERED SHOWERS WILL CONTINUE ALONG AND EAST OF THE I-44/I-55 CORRIDOR WITH MORE ISOLATED PRECIP WEST. WATCH OUT FOR LLWS THIS EVENING AS A 40-50KT LOW LEVEL JET RAMPS UP...AND A FEW THUNDERSTORMS WILL ALSO BE POSSIBLE ALONG AND EAST OF I-44 DUE TO THE JET AS WELL. CARNEY && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && WFO LSX
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE ST LOUIS MO 415 PM CST SAT DEC 12 2009 ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027- 034>036-041-042-047>052-059>065-072>075-084-085-099-131130- GREENE IL-MACOUPIN IL-MONTGOMERY IL-BOND IL-FAYETTE IL-CLINTON IL- MARION IL-WASHINGTON IL-RANDOLPH IL-ADAMS IL-BROWN IL-PIKE IL- CALHOUN IL-JERSEY IL-MADISON IL-ST. CLAIR IL-MONROE IL-KNOX-LEWIS- SHELBY-MARION-MONROE-RALLS-PIKE-BOONE-AUDRAIN-MONITEAU-COLE-OSAGE- CALLAWAY-MONTGOMERY-LINCOLN-GASCONADE-WARREN-ST. CHARLES-FRANKLIN- ST. LOUIS-ST. LOUIS CITY-JEFFERSON-CRAWFORD-WASHINGTON- ST. FRANCOIS-STE. GENEVIEVE-IRON-MADISON-REYNOLDS- 415 PM CST SAT DEC 12 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN AND CENTRAL MISSOURI AS WELL AS WEST CENTRAL AND SOUTHWEST ILLINOIS. .DAY ONE...TONIGHT NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED TONIGHT. && FOR A GRAPHICAL VERSION OF THIS INFORMATION SEE OUR WEBPAGE AT (LOWERCASE)... HTTP://WWW.WEATHER.GOV/LSX/?N=HWO1 KANOFSKY
The St Louis radar (KLSX), 64 km away, was scanning. The volume nearest the first event began at 00:29 UTC.
1 hail. Local standard time, as filed.
Brief period of quarter sized hail with intermixed smaller hail fell at Meramec State Park.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Missouri in 2009Every state in 2009This day in weather historyWarnings in Missouri, December 2009
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 208170.