With numerous old outflow boundaries over the area from the morning thunderstorm activity, additional thunderstorms developed over the region during the afternoon and early evening hours of August 4th.
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.
With numerous old outflow boundaries over the area from the morning thunderstorm activity, additional thunderstorms developed over the region during the afternoon and early evening hours of August 4th.
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 Aug 4, 11:55 AM CST, 1 hour 30 minutes earlier.
AREA FORECAST DISCUSSION...UPDATED AVIATION NATIONAL WEATHER SERVICE ST LOUIS MO 1255 PM CDT TUE AUG 4 2009 .UPDATE... /952 AM CDT TUE AUG 4 2009/ PRECIP SHOULD CONTINUE TO WANE AS MCS UNDERGOES TYPICAL DIURNAL WEAKENING. WEAKENING TREND HAS ALSO PUT AN END TO THE HEAVY RAIN THREAT...SO HAVE DROPPED FFA. UPDATE FOR THE REST OF THIS MORNING ESSENTIALLY EXTRAPOLATION OF ONGOING RADAR TRENDS. NO CHANGES TO AFTERNOON ATTM...AND WELL SAVE AFTN TWEEKS UNTIL WE SEE HOW REST OF THIS MORNING SHAKES OUT. TRUETT && .DISCUSSION... /404 AM CDT TUE AUG 4 2009/ TODAY...ELEVATED CONVECTION FINALLY BEGINNING TO DEVELOP ACROSS NORTHERN MISSOURI AND SOUTHERN IOWA WITH BEST ORGANIZATION AT 3 AM NOTED ACROSS NORTHWEST MISSOURI. ONLY MODEL THAT SEEMS TO HAVE ANY KIND OF HANDLE ON THE CURRENT SITUATION IS THE 4KM NCEP WRF...WHICH BRINGS THE DEVELOPING MCS THROUGH THE NORTHERN HALF OF THE CWA DURING THE MORNING. BELIEVE THIS CONVECTIVE ACTIVITY WILL EXIT CWA TO THE EAST DURING THE AFTERNOON WITH TEMPERATURES RECOVERING QUICKLY. STILL CANT RULE OUT REDEVELOPMENT THIS AFTERNOON AS ATMOSPHERE TRIES TO RECOVER IN THE WAKE OF THE MCS. DESPITE THE LACK OF RAINFALL OVERNIGHT...BELIEVE IT IS PRUDENT TO EXTEND THE EXISTING FLASH FLOOD WATCH UNTIL 18Z...AS PWATS REMAIN NEAR 2 INCHES...AND LOCALLY HEAVY RAINFALL COULD CAUSE SOME PROBLEMS THIS MORNING. CVKING WEDNESDAY...PRIMARY CONCERN FOR WED IS CONVECTION CHANCES UNDER CONTINUED NORTHWEST FLOW ALOFT WITH THETAE BDRY SINKING SWD THROUGH THE REGION. WHILE SOME SCATTERED THUNDERSTORMS ARE POSSIBLE DURING THE DAY /ESPECIALLY ALONG REMNANT OUTFLOW BDRYS/...THE BEST CHANCE FOR ORGANIZED CONVECTION APPEARS TO BE IN THE LATE AFTERNOON AND EVENING. ECMWF/UKMET/GFS SOLUTIONS SUGGEST A SHORTWAVE TROF WILL APPROACH THE BISTATE REGION ON WEDNESDAY AFTERNOON AND EVENING. FORCING FROM THIS SHORTWAVE IN AN WILL AID THUNDERSTORM DEVELOPMENT IN AN UNSTABLE ATMOSPHERE. WENT WITH CHC POPS FOR WEDNESDAY EVENING GIVEN THE USUAL UNCERTAINTIES WITH EMBEDDED SHORTWAVES IN NW FLOW ALOFT AND RECENT MODEL DIFFICULTIES WITH THUNDERSTORM PLACEMENT. THURSDAY THROUGH SATURDAY...ECMWF AND GFS CONTINUE TO ADVERTISE A PATTERN CHANGE WITH THE WRN CONUS RIDGE FINALLY PROGRESSING E INTO THE CENTRAL US. INITIALLY RELUCTANT TO BUY INTO THIS SOLUTION SINCE BOTH MODELS HAVE RESOLUTELY SHOWN THIS SAME DAY 5-7 PATTERN SHIFT FOR THE LAST SEVERAL DAYS...BUT WATER VAPOR IMAGERY DOES SHOW THAT THE DEFORMATION ZONE W OF THE PACIFIC COAST CUTOFF LOW IS BECOMING LESS WELL DEFINED...INDICATING THAT A PATTERN SHIFT MAY ALREADY BE OCCURRING. BEGAN NUDGING HIGH TEMPERATURES SLIGHTLY UPWARD BUT NOT AS HIGH AS MOS GUIDANCE. WHEN THE PATTERN SHIFT MATERIALIZES...HOT WEATHER WILL RETURN TO THE BISTATE REGION WITH HEAT INDEX VALUES OVER 100 DEGREES POSSIBLE OVER THE WEEKEND. KANOFSKY && .AVIATION... /1246 PM CDT TUE AUG 4 2009/ FOR THE 18Z TAFS... PRIMARY CONCERN FOR AVIATION INTERESTS THROUGH THE AFTERNOON AND EARLY EVENING WILL BE CONVECTION. ATMOSPHERE REMAINS VERY UNSTABLE GENERALLY SOUTH OF THE I-70 CORRIDOR. CONVECTIVE DEBRIS CLOUDS ARE BREAKING UP ALLOWING FOR SOME SURFACE HEATING...AND AN OUTFLOW BOUNDARY FROM EARLIER CONVECTION IS DRIFTING SOUTH OF THE MISSOURI RIVER AT THIS TIME. THEREFORE I THINK WELL SEE SCATTERED STRONG TO SEVERE THUNDERSTORMS REDEVELOP SOUTH OF THE MISSOURI RIVER LATER THIS AFTERNOON AND CONTINUE INTO THE EARLY EVENING. COULD SEE SOME FOG DEVELOP LATE TONIGHT AFTER THE CLOUDS CLEAR OUT...BUT AM NOT CONFIDENT ENOUGH AT THIS TIME TO INCLUDE IT IN THE TERMINAL FORECASTS. ELSEWHERE AND OTHERWISE...VFR CONDITIONS WILL PREVAIL OUTSIDE OF THUNDERSTORMS WITH VARIABLE WINDS...BECOMING NORTH- NORTHEAST TONIGHT AS A WEAK COLD FRONT DRIFTS THROUGH THE AREA. CARNEY && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && WFO LSX
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE ST LOUIS MO 1024 AM CDT TUE AUG 4 2009 ILZ058>060-064-065-069-070-074-079-095>102-MOZ018-019-026-027- 034>036-041-042-047>052-059>065-072>075-084-085-099-051145- 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- 1024 AM CDT TUE AUG 4 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN AND CENTRAL MISSOURI AS WELL AS WEST CENTRAL AND SOUTHWEST ILLINOIS. .DAY ONE...TODAY AND TONIGHT THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE ACROSS THE AREA FOR THE REST OF THE DAY...INTO THE EVENING HOURS. SOME OF THE STORMS COULD BE SEVERE. THE PRIMARY SEVERE WEATHER THREATS ARE DAMAGING WIND GUSTS IN EXCESS OF 60 MPH AND LARGE HAIL. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THERE IS A CHANCE OF THUNDERSTORMS ON WEDNESDAY AND THURSDAY WHILE A FRONTAL BOUNDARY REMAINS IN PLACE ACROSS MISSOURI AND ILLINOIS. SOME OF THE THUNDERSTORMS COULD BE SEVERE WITH LOCALLY HEAVY RAINFALL. ALTHOUGH MOST OF THE SUMMER HAS BEEN COOLER THAN NORMAL...MORE TYPICAL LEVELS OF HEAT AND HUMIDITY WILL RETURN TO THE REGION OVER THE WEEKEND WITH HEAT INDEX VALUES OF 100 TO 105 DEGREES. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION CONTINUES TO BE A POSSIBILITY THROUGHOUT THE DAY. && FOR A GRAPHICAL VERSION OF THIS INFORMATION SEE OUR WEBPAGE AT (LOWERCASE)... HTTP://WWW.WEATHER.GOV/LSX/?N=HWO1 CARNEY
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE ST LOUIS MO 825 AM CDT TUE AUG 4 2009 ILZ059-060-041415- MACOUPIN IL-MONTGOMERY IL- 825 AM CDT TUE AUG 4 2009 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN MACOUPIN AND NORTHERN MONTGOMERY COUNTIES UNTIL 915 AM CDT... AT 823 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM NEAR FARMERSVILLE...OR 5 MILES SOUTHEAST OF VIRDEN...MOVING EAST AT 30 MPH. HAIL UP TO THE SIZE OF PENNIES AND WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THIS STORM. LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE... NOKOMIS... FARMERSVILLE... RAYMOND... WHITE OAK... WITT... WAGGONER... HONEY BEND... HARVEL... COALTON... WENONAH... OHLMAN... THIS STORM MAY INTENSIFY...AND A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR THIS AREA. BE CERTAIN TO MONITOR LOCAL RADIO AND TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS...FOR ADDITIONAL INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE. TILLY
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ST LOUIS MO
925 AM CDT TUE AUG 04 2009
..TIME.. ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE.. ....MAG.... ..COUNTY LOCATION.. ST.. ...SOURCE....
..REMARKS..
0915 AM TSTM WND GST 4 N RAMSEY 39.20N 89.11W
08/04/2009 E50 MPH FAYETTE IL TRAINED SPOTTER
EST 40-50 MPH GUSTS
&&
EVENT NUMBER LSX0900063
MILLERPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ST LOUIS MO
934 AM CDT TUE AUG 04 2009
..TIME.. ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE.. ....MAG.... ..COUNTY LOCATION.. ST.. ...SOURCE....
..REMARKS..
0920 AM TSTM WND GST STURGEON 39.24N 92.28W
08/04/2009 E50 MPH BOONE MO TRAINED SPOTTER
EST 40-50 MPH GUST. ONE BRANCH BLOWN DOWN IN YARD.
&&
EVENT NUMBER LSX0900064
SCHWEDLERPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE ST LOUIS MO
959 AM CDT TUE AUG 04 2009
..TIME.. ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE.. ....MAG.... ..COUNTY LOCATION.. ST.. ...SOURCE....
..REMARKS..
0720 AM TSTM WND DMG 6 NE MOUNT STERLING 40.05N 90.68W
08/04/2009 BROWN IL LAW ENFORCEMENT
RELAYED THROUGH BROWN COUNTY SO...IN RIPLEY...TREES AND
POWER LINES DOWN
&&
EVENT NUMBER LSX0900065
MILLERThe St Louis radar (KLSX), 60 km away, was scanning. The volume nearest the first event began at 19:25 UTC.
1 thunderstorm wind, 1 hail. Local standard time, as filed.
Thunderstorm winds blew down several large trees including one on Highway W in Stanton, which landed on an unoccupied truck.
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, August 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: 188602, 188594.