An intense low pressure system moved northeast across northern Illinois early Wednesday morning and continued to strengthened as it pushed across Lake Michigan and the lower portion of Michigan. This intense low pressure resulted in very strong winds across much of central Indiana late Wednesday morning and early afternoon.
Every event with a place to put it; 5 filed by county or forecast zone are drawn at its center, in a lighter ring. 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 IND wrote it up.
An intense low pressure system moved northeast across northern Illinois early Wednesday morning and continued to strengthened as it pushed across Lake Michigan and the lower portion of Michigan. This intense low pressure resulted in very strong winds across much of central Indiana late Wednesday morning and early afternoon.
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 Indianapolis, IN wrote its last area forecast discussion before the first event at Dec 9, 10:15 AM EST, 49 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE INDIANAPOLIS IN 1015 AM EST WED DEC 9 2009 .UPDATE...FOR THIS AFTERNOON. ZONES WERE UPDATED TO PUT MORE EMPHASIS ON FALLING TEMPERATURES FOR THIS AFTERNOON. TEMPERATURES OVER WESTERN ILLINOIS AND CENTRAL MISSOURI HAVE FALLEN INTO THE UPPER TEENS AND NAM 2 METER TEMPERATURES ARE FORECASTER TO BE AS LOW AS 20 DEGREES IN SOME AREAS BY 00Z. PRECIPITATION HAS ALREADY CHANGED TO SNOW SHOWERS FROM INDY AND WESTWARD AND ANY RAIN SHOWERS SHOULD CHANGE TO ALL SNOW ELSEWHERE IN A FEW HOURS. VISIBILITIES WERE FROM 1 TO 2 MILES FROM LAFAYETTE TO CENTRAL ILLINOIS. THIS AREA SHOULD MOVE THROUGH QUICKLY...BUT SNOW AMOUNTS UP TO A THIRD OF AN INCH MAY OCCUR ACROSS OUR NORTHERN SECTIONS. && .SHORT TERM... A POWERFUL LOW PRESSURE SYSTEM HAS FINALLY MOVED INTO THE MIDWEST...AND IS PRODUCING AN ARRAY OF WEATHER FROM THE DEEP SOUTH TO THE UPPER MIDWEST. SHOWERS AND THUNDERSTORMS HAVE FORMED ALONG A COLD FRONT STRETCHING FROM THE OHIO VALLEY TO THE GULF OF MEXICO. FURTHER NORTH...HEAVY SNOW AND STRONG WINDS ARE MOVING THROUGH THE GREAT LAKES AREA. THE SYSTEM CONTINUES TO DEEPEN WITH PRESSURE DROPS OF OVER 30 MB. THE MAIN FOCUS OF FORECAST PERIOD IS THE PRECIPITATION TYPE/TIMING THIS MORNING AND THE HIGH WINDS. NO CHANGES WERE MADE TO THE TIMING/TYPE OF PRECIPITATION TODAY. FORECAST IS STILL ON TRACK FOR RAIN THROUGH THE EARLY MORNING HOURS AS TEMPERATURES HOLD STEADY IN THE MID 40S THROUGH MID MORNING. THE WESTERN PORTIONS OF FORECAST AREA COULD STILL SEE A MIXTURE OF RAIN/SNOW BY LATE MORNING AS COLD AIR BEGINS FILTERING INTO INDIANA. THE RAIN/SNOW MIX WILL TRANSITION TO ALL SNOW ACROSS ENTIRE FORECAST AREA AFTER NOON AS TEMPERATURES BEGIN PLUMMETING. HOWEVER...THERE COULD BE A LULL IN PRECIPITATION BETWEEN THE WED 15Z/18Z TIME FRAME AS ISENTROPIC LIFT SHUTS DOWN AND DRY SLOT MOVES INTO AREA. HOWEVER...WRAPAROUND MOISTURE WILL MOVE ACROSS INDIANA AROUND WED 18Z WHEN PRECIPITATION WILL TRANSITION TO ALL SNOW. SNOW ACCUMULATIONS WILL BE MINIMAL THOUGH AS MOISTURE QUICKLY MOVES TO THE NORTHEAST. WINDS ARE CURRENTLY GUSTING TO 40 MPH OVER PORTIONS OF THE AREA. STILL TORN ON WHETHER TO ISSUE THE HIGH WIND WARNING. THE PRESSURE GRADIENT AND UPPER LEVEL JET APPEAR TO BE THE STRONGEST JUST SOUTH OF COUNTY WARNING AREA. BUT...GUSTS ARE ALREADY UP TO 40 MPH AND WILL GET STRONGER THIS AFTERNOON. WILL MONITOR THIS SITUATION. DANGEROUS WINDCHILLS ARE STILL EXPECTED THROUGH FRIDAY WITH TEMPERATURES WELL BELOW ZERO. A WINDCHILL ADVISORY MAY HAVE TO BE ISSUED AFTER NEW MODELS COME IN. THERE IS TOO MUCH DISCREPANCY RIGHT NOW TO ISSUE ADVISORY. THE CANADIAN SEEMED TOO COLD YESTERDAY...BUT THE NAM HAS NOW COME INTO AGREEMENT WITH IT...LEAVING THE GFS AS THE OUTLIER. TRENDED WELL BELOW GUIDANCE DUE TO HOW FAST NAM HAS COME INTO AGREEMENT WITH GEM. HOWEVER...GEM IS STILL ON ITS OWN WITH REGARD TO FRIDAY NIGHT LOWS...FORECASTING SINGLE DIGITS WHILE OTHER MODELS ARE INDICATING LOW 20S. LONG TERM.../FRIDAY THROUGH TUESDAY/ IN THE EXTENDED PERIOD...ARCTIC AIR WILL BE ENTRENCHED ACROSS THE NORTHERN TIER STATES...WHILE A MOIST AND RATHER ACTIVE PATTERN OCCURS ACROSS THE SOUTHERN U.S. ON FRIDAY HIGH PRESSURE WILL MOVE FROM THE OHIO VALLEY TO MID ATLANTIC STATES. THE EUROPEAN...GEM AND GFS MODELS MOVE AN UPPER LEVEL DISTURBANCE ACROSS THE DEEP SOUTH LATE FRIDAY AND FRIDAY NIGHT. THE EUROPEAN BRINGS MOISTURE FROM THIS SYSTEM AS FAR NORTH AS INDIANA LATE FRIDAY NIGHT AND SATURDAY...WHILE THE GEM...GFS MODELS KEEP PRECIPITATION SUPPRESSED TO THE SOUTH. HPC WENT CLOSE TO THE EUROPEAN. BUT WITH THE GEM AND GFS COMING IN DRIER WILL DOWNPLAY PRECIPITATION A LITTLE. THIS SOUTHERN SYSTEM MOVES ON TO THE EAST BY SUNDAY. THE EUROPEAN BRINGS AN UPPER LEVEL DISTURBANCE ACROSS OUR AREA BY MONDAY. BOTH THE GFS AND GEM SHOW VERY LITTLE MOISTURE NORTH OF THE OHIO RIVER...SO WILL DOWNPLAY PRECIPITATION CHANCES AGAIN TO A SLIGHT CHANCE LATER SUNDAY NIGHT AND MONDAY. THE 12Z GFS DEVELOPS A STRONG UPPER TROUGH ACROSS OUR REGION BY TUESDAY. IT ALSO TAKES A STRONG SURFACE LOW FROM THE NORTHERN GULF TO THE MID ATLANTIC STATES AND IN TURN SPREADS PRECIPITATION ACROSS OUR REGION. I HAVE LOW CONFIDENCE ON THIS AND WILL MENTION SLIGHT CHANCES OF PRECIPITATION MONDAY NIGHT AND THEN KEEP TUESDAY DRY. AS FAR AS TEMPERATURES ARE CONCERNED...I TRENDED A FEW DEGREES BELOW HPC NUMBERS...BUT NOT QUITE AS COLD AS MEX. ON MONDAY NIGHT ...I WENT SLIGHTLY WARMER THAN HPC TEMPERATURES AS THERE COULD BE QUITE A BIT OF CLOUDINESS ACROSS OUR REGION. && .AVIATION DISCUSSION...FOR THE 12Z TAFS A MAJOR WEATHER PROBLEM FOR AVIATION TODAY WILL BE EXTREMELY STRONG WIND. A VERY STRONG LOW PRESSURE SYSTEM WILL MOVE THROUGH THE GREAT LAKES AREA TODAY. THE VERY TIGHT PRESSURE GRADIENT WILL GIVE WIND GUSTS UP TO 45 KTS. WIND DIRECTION WILL BE FROM THE SW THIS MORNING SHIFTING TO THE WEST DURING THE LATE AFTERNOON. MVFR CEILINGS WILL OCCUR ACROSS THE AREA. SNOW WAS WRAPPING AROUND THE LOW. THIS WILL MOVE INTO INDIANA LATER IN THE MORNING. THE SNOW SHOULD NOT DECREASE VSBYS BELOW MVFR LEVELS. AS THE LOW CONTINUES TO PULL NE THE WINDS WILL DECREASE. BY 04Z WINDSPEEDS WILL ONLY BR AROUND 20 KTS. THE SNOW WILL MOVE OUT BUT MVFR CEILINGS WILL REMAIN. && .IND WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 1 AM EST THURSDAY FOR INZ021-028>031-035>049- 051>057-060>065-067>072. && UPDATE...JH SHORT TERM...TDUD LONG TERM...JH AVIATION...SH
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE INDIANAPOLIS IN 426 AM EST WED DEC 9 2009 INZ021-028>031-035>049-051>057-060>065-067>072-100930- CARROLL-WARREN-TIPPECANOE-CLINTON-HOWARD-FOUNTAIN-MONTGOMERY- BOONE-TIPTON-HAMILTON-MADISON-DELAWARE-RANDOLPH-VERMILLION-PARKE- PUTNAM-HENDRICKS-MARION-HANCOCK-HENRY-VIGO-CLAY-OWEN-MORGAN- JOHNSON-SHELBY-RUSH-SULLIVAN-GREENE-MONROE-BROWN-BARTHOLOMEW- DECATUR-KNOX-DAVIESS-MARTIN-LAWRENCE-JACKSON-JENNINGS- 426 AM EST WED DEC 9 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL INDIANA. .DAY ONE...TODAY AND TONIGHT. SUSTAINED WEST/SOUTHWESTERLY WINDS OF 30 TO 40 MPH AND GUSTS IN EXCESS OF 55 MPH ARE EXPECTED THROUGH THIS EVENING. LIGHT SNOW ACCUMULATIONS OF LESS THAN AN INCH ARE POSSIBLE LATE WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT. BITTER COLD WEATHER WILL MOVE IN TONIGHT WITH WIND CHILLS BELOW ZERO OVER NORTHERN SECTIONS...AND SINGLE DIGITS OVER THE SOUTHERN AREAS. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. BITTER COLD WEATHER WILL CONTINUE THROUGH FRIDAY MORNING. WIND CHILLS WILL STAY BELOW ZERO. A MIX OF RAIN AND SNOW ARE POSSIBLE ON SATURDAY AND MONDAY. CONTINUE TO MONITOR THESE DEVELOPING WEATHER SITUATIONS WITH NOAA ALL HAZARDS RADIO OR YOUR LOCAL MEDIA. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGE TO REPORT STRONG WIND GUST MEASUREMENTS OR WIND DAMAGE. && MORE INFORMATION...ALONG WITH OTHER WEATHER...HYDROLOGICAL AND CLIMATE INFORMATION CAN BE FOUND...AT HTTP://WEATHER.GOV/IND (ALL LOWERCASE) 77
The national radar mosaic for the moment the first event began.
4 strong wind, 1 high wind. Local standard time, as filed.
A non-thunderstorm wind gust of 54 MPH was measured by the ASOS at the Indianapolis International Airport.
A non-thunderstorm wind gust of 51 MPH was measured by the ASOS at Terre Haute.
A non-thunderstorm wind gust of 54 MPH was measured by the AWOS at Kokomo.
A non-thunderstorm wind gust of 59 MPH was measured by the AWOS at Mount Comfort, approximately 5 miles ESE of Lawrence.
A non-thunderstorm wind gust of 54 MPH was estimated by an emergency manager, approximately 6 miles N of Anderson.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Indiana in 2009Every state in 2009This day in weather historyWarnings in Indiana, 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: 203982, 203983, 203984, 203985, 203987.