A prolonged period of thunderstorms occurred over southeast Illinois in a very moist southerly wind flow. A weak low pressure center just northwest of the Ohio River's confluence with the Mississippi River helped to focus the moisture and convergence.
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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 PAH wrote it up.
A prolonged period of thunderstorms occurred over southeast Illinois in a very moist southerly wind flow. A weak low pressure center just northwest of the Ohio River's confluence with the Mississippi River helped to focus the moisture and convergence. A 500 mb shortwave rotating northeast across the Lower Ohio Valley further aided the 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 Paducah, KY wrote its last area forecast discussion before the first event at Sep 20, 1:31 PM CST, 2 hours 59 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PADUCAH KY 231 PM CDT SUN SEP 20 2009 .DISCUSSION... NICE FETCH OF TROPICAL MOISTURE AMPLY TAPPED AS SEEN ON 88D/MOSAIC...HIGHEST POPS/BEST COVERAGE EAST OF MS RIVER. BNA 12Z SOUNDING SHOWS PWS NEAR 2 INCHES. NAM MODELS ONGOING CONVECTION WELL...AND KEEPS ERN 1/3 FA WET THIS EVENING...BEFORE TAPERING OFF POPS WEST TO EAST OVERNIGHT. COINCIDING W/THIS TAPERING OFF WILL BE FORMATION OF AREAS OF FOG FROM WEST TO EAST...SO HAVE INCLUDED THIS TRENDING AS WELL. GIVEN DEPTH OF MOISTURE WILL HIT HWO AND SHORT FUSE PRODUCTS HARD ON HEAVY RAIN/POTENTIAL WATER ISSUES BUT GIVEN TIME SPREAD OF WHAT WILL BECOME GENERALLY LIGHT-MODERATE RAIN DO NOT ANTICIPATE WATCH NEEDED ATTM...NOT TO SAY MINOR FLOODING WONT OCCUR. RELATIVE LULL LATE TONIGHT-EARLY MONDAY LOOKS TO PULSE AGAIN MON NIGHT-TUESDAY AS SURFACE LOW EJECTS ACROSS AR/MO WITHIN DEEP/WET SSWLYS. THIS PULSEY TREND MORE OR LESS CONTINUES THRU MID WEEK WITH ON/OFF AGAIN POPS KEEPING A WET FORECAST...BUT NOT NECESSARILY A CONTINUALLY WET PERIOD. THE BIGGEST FORECAST CHALLENGE IS MID WEEK ON...WHERE THE GFS/DGEX SUGGEST A BUILDING SERN U.S. RIDGE WILL SHUNT THE UPPER LOW WELL TO THE WEST AND EFFECTIVELY END OUR POPS. MEANWHILE THE HPC AND COLLABORATIVELY PREFERRED GEFS/ECMWF SLOWLY TRANSLATE THE LOW/UPPER TROF AND EVENTUALLY AN ATTENDANT COLD FRONT ACROSS THE AREA BY NEXT WEEKEND...FINALLY ENDING POPS BY DAY 7-8. HOWEVER IT TOO BUILDS AN UPPER RIDGE INTO/ACROSS THE AREA...ONLY IT POWER DRIVES THE LOW ACROSS IT DURING THE WEEK. AT THIS POINT IN THE GAME WILL HAVE TO STICK W/CONSENSUS AND FORECAST CONTINUITY...MAINTAINING A POP MENTION BUT MUTING IT FROM ECMWF BULLSEYE POPS. NEW MOS IS CLOSE TO GOING TEMPS/FORECAST TEMPS AND SO ONLY MINOR TWEEKS NEEDED THIS PACKAGE. .AVIATION... AS A SFC AREA OF LOW PRESSURE MOVES NWD THROUGH THE REGION...SHWRS AND TSTMS AND MVFR CIGS WILL REMAIN MOST LIKELY EAST OF THE MS RIVER INTO THE EARLY EVE. AFTER THAT...PCPN COVERAGE SHOULD DECREASE. OVNGT...WITH PLENTY OF LOW LEVEL MOISTURE IN PLACE...VSBYS ARE EXPECTED TO DECREASE TO IFR IN SPOTS. IN ADDITION...IFR CIGS ARE MOST LIKELY IN THE EAST OVNGT. CONDITIONS SHOULD IMPROVE TEMPORARILY BY MIDDAY MON. && .PAH WATCHES/WARNINGS/ADVISORIES... KY...NONE. MO...NONE. IL...NONE. IN...NONE. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE PADUCAH KY 519 AM CDT SUN SEP 20 2009 ILZ075>078-080>094-INZ081-082-085>088-KYZ001>022-MOZ076-086-087- 100-107>112-114-211030- JEFFERSON-WAYNE IL-EDWARDS-WABASH-PERRY IL-FRANKLIN-HAMILTON- WHITE-JACKSON-WILLIAMSON-SALINE-GALLATIN-UNION IL-JOHNSON-POPE- HARDIN-ALEXANDER-PULASKI-MASSAC-GIBSON-PIKE-POSEY-VANDERBURGH- WARRICK-SPENCER-FULTON-HICKMAN-CARLISLE-BALLARD-MCCRACKEN-GRAVES- LIVINGSTON-MARSHALL-CALLOWAY-CRITTENDEN-LYON-TRIGG-CALDWELL- UNION KY-WEBSTER-HOPKINS-CHRISTIAN-HENDERSON-DAVIESS-MCLEAN- MUHLENBERG-TODD-PERRY MO-BOLLINGER-CAPE GIRARDEAU-WAYNE MO-CARTER- RIPLEY-BUTLER-STODDARD-SCOTT-MISSISSIPPI-NEW MADRID- 519 AM CDT SUN SEP 20 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHERN ILLINOIS...SOUTHWEST INDIANA...WESTERN KENTUCKY AND SOUTHEAST MISSOURI. .DAY ONE...TODAY AND TONIGHT SCATTERED THUNDERSTORMS CROSS THE REGION TODAY AND TONIGHT AS LOW PRESSURE MOVES UP THE MISSISSIPPI RIVER VALLEY. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE WITH SOME OF THESE STORMS. IN ADDITION...A FEW STORMS MAY APPROACH SEVERE LEVELS AS A WARM FRONT LIFTS NORTH ACROSS THE REGION. AN ISOLATED TORNADO CANNOT BE RULED OUT. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY A RISK OF THUNDERSTORMS WILL ALSO CARRY INTO NEXT WEEK. AT THIS TIME...SEVERE STORMS ARE NOT ANTICIPATED. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED...THOUGH SPOTTERS SHOULD RELAY ANY HEAVY RAINFALL OR FLOODING REPORTS TO THE NATIONAL WEATHER SERVICE.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE
456 PM CDT SUN SEP 20 2009
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0450 PM FLASH FLOOD SANTA CLAUS 38.12N 86.93W
09/20/2009 SPENCER IN LAW ENFORCEMENT
STATE ROAD 245 WAS UNDER WATER AND CLOSED.
&&
KELLYHPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE
501 PM CDT SUN SEP 20 2009
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0440 PM FLASH FLOOD ROCKPORT 37.88N 87.05W
09/20/2009 SPENCER IN PUBLIC
3.8 INCES OF RAIN FALL. RAIN STILL IN PROGRESS
&&
KELLYHPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE
503 PM CDT SUN SEP 20 2009
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0450 PM FLASH FLOOD CHRISNEY 38.01N 87.03W
09/20/2009 SPENCER IN LAW ENFORCEMENT
STATE ROAD 231 HAD ONE LANE FLOODED.
&&
KELLYHThe national radar mosaic for the moment the first event began.
1 heavy rain. Local standard time, as filed.
Route 130 was flooded and reduced to one lane of traffic for about a mile. A trained spotter three miles west of West Salem measured 5.1 inches, mostly during the evening.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2009Every state in 2009This day in weather historyWarnings in Illinois, September 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: 194438.