Scattered thunderstorms developed across central Illinois during the afternoon of August 16th in association with a weak upper-level impulse. One cell produced gusty winds and minor tree damage in Urbana.
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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 ILX wrote it up.
Scattered thunderstorms developed across central Illinois during the afternoon of August 16th in association with a weak upper-level impulse. One cell produced gusty winds and minor tree damage in Urbana.
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 Lincoln, IL wrote its last area forecast discussion before the first event at Aug 16, 1:54 PM CST, 2 hours 6 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 254 PM CDT SUN AUG 16 2009 .DISCUSSION... ISSUED 254 PM CDT SUN AUG 16 2009 MODELS REMAIN SIMILAR IN THE OVERALL UPPER LEVEL PATTERN AND SFC FEATURES. THE DIFFERENCES ARE IN THE DETAILS OF LOCATION...TIMING AND AMOUNT OF QPF EXPECTED NEXT 72HRS. MAIN CONCERNS THIS PACKAGE WILL BE POPS AND LOCATION OF PCPN NEXT 48HRS. TONIGHTS FORECAST WILL BE MORE OF A COMBINATION OF EXTRAPOLATION OF CURRENT RADAR TRENDS WITH SHORT TERM MODEL FORECAST. REMAINDER OF FORECAST WILL BE BLEND OF SHORT TERM MODELS. IN THE LONG TERM...MODELS REMAIN SIMILAR AND A BLEND HERE WILL WORK AS WELL. SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT RADAR TRENDS INDICATE PCPN MOVING THROUGH QUICKER THAN 4KM WRF SHOWED AND SEEMS TO BE SIMILAR TO WHAT 12Z NAM-WRF IS SHOWING AS WELL. BASED ON THIS...WILL HAVE HIGHEST POPS ACROSS THE MIDDLE WITH LOWER CHC POPS IN THE NORTHWEST AND SOUTHEAST...FOR TONIGHT. ALL THIS PCPN IS AHEAD OF THE MAIN FRONT WHICH IS BACK IN EASTERN IOWA. AS THE FRONT INCHES CLOSER TOMORROW...IT BEGINS TO LOSE DEFINITION AS SFC WINDS GET WEAK AND GRADIENT LOOSENS. ANY OUTFLOW BOUNDARIES FROM TONIGHTS CONVECTION WILL ALSO MUDDY THE SFC PATTERN TOMORROW. SO BASED ON THIS...WILL KEEP LIKELY POPS TOWARD THE NORTHWEST TOMORROW AS THE WEAK FRONT MOVES INTO THE AREA WITH CHANCE POPS IN THE SOUTHEAST. THIS WEAK FRONT WILL DROP INTO THE CWA MONDAY NIGHT BUT BECOME PARALLEL WITH THE MID LEVEL FLOW...WHICH WILL CAUSE IT TO REALLY WASHOUT AND BE HARD TO FIND. AS IT CONTINUES ITS SLOW PACE TO THE SOUTH...CHC POPS WILL REMAIN WARRANTED ALONG THE FRONT THROUGH TUE. THERE IS SOME UNCERTAINTY AS TO IF THERE WILL BE PCPN FOR TUE NIGHT IN THE CWA AS THE FRONT SHOULD HAVE EITHER WASHED OUT BY THEN OF BEGIN TO LIFT NORTHWARD AS A WARM FRONT. FOR NOW...UNTIL THINGS BECOME MORE CLEAR...WILL HAVE CHC POPS FOR TUE NIGHT AND WED. BY WED NIGHT...THINGS BECOME MORE CLEAR AS ANOTHER SYSTEM PUSHES INTO THE AREA FROM THE NORTHWEST. THIS SYSTEM WILL BE IN RESPONSE TO SOME ENERGY THAT WILL DROP INTO THE NORTHERN PLAINS AND STRENGTHEN A MID LEVEL TROUGH IN THE MIDWEST. SO HAVE INCREASED POPS TO LIKELY IN THE NORTHWEST AND CHANCE IN THE SOUTHEAST. THE ASSOCIATED FRONT WILL PUSH THROUGH THE REGION WED NIGHT INTO THUR. LARGE CHANGE IN DAYTIME TEMPS THROUGH THE PERIOD AS SOUTHEASTERN AREAS SEE SUNSHINE AND OTHER AREAS EXPERIENCE RAIN AND CLOUDS. SO LOOKING FOR WARMER TEMPS IN THE SOUTHEAST AND COOLER IN THE NORTH. MODEL GUIDANCE DOES RELATIVELY GOOD JOB WITH THIS THROUGH WED. LONG TERM...THURSDAY THROUGH SUNDAY AS MENTIONED...TROUGH WILL BE STRENGTHENING AT THE BEGINNING OF THE PERIOD...WITH A WAVE DROPPING INTO THE REGION THUR AND THUR NIGHT. WILL KEEP CHC PCPN WITH THE FRONT AS IT MOVES THROUGH THE CWA AND THEN GO DRY AFTER PASSAGE. COULD BE SOME INSTABILITY SHOWERS/T-STORMS FRIDAY BUT WOULD RATHER WAIT UNTIL HAVE SEEN FEW MORE MODELS RUNS BEFORE PUTTING THIS IN. OTHERWISE REMAINDER OF EXTENDED FORECAST FOR FRIDAY THROUGH THE WEEKEND IS DRY FOR NOW. TEMPS WILL GET COOLER AS PATTERN CHANGES AND AREA BEGINS TO SEE MORE NORTHERLY OR NORTHWESTERLY FLOW. MEX GUIDANCE LOOKS OK BUT APPEARS TO BE TOO COOL IN THE LATER PERIODS. AUTEN && .AVIATION... ISSUED 1246 PM CDT SUN AUG 16 2009 MAIN ISSUE FOR THIS ROUND OF TAFS IS MERELY THE SLOW MOVING LINE OF TS THAT IS HOLDING TOGETHER RATHER WELL AS IT CROSSES THE CWA. DROPPING THE CIGS AND VSBYS DOWN TO MVFR/IFR AS THE FRONT OF THE LINE PASSES OVER. THIS TREND SHOULD CONTINUE INTO THE EVENING. SHOWERS STILL POSSIBLE IN THE OVERNIGHT HOURS...BUT MODELS HAVE DECREASED CONSIDERABLY IN COVERAGE BEHIND THE INITIAL LINE. WITH INCONSISTENCY THERE...HAVE MAINTAINED A SIMPLE VCSH UNTIL MORE SOLID. ALSO...WITH THREAT FOR THUNDER STILL THERE...PUT IN THE CB AS WELL TO CONTINUE THE TREND. HJS && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE LINCOLN IL 301 PM CDT SUN AUG 16 2009 ILZ027>031-036>038-040>054-061-171100- CASS-CHAMPAIGN-CHRISTIAN-DE WITT-FULTON-KNOX-LOGAN-MACON-MARSHALL- MASON-MCLEAN-MENARD-MORGAN-MOULTRIE-PEORIA-PIATT-SANGAMON- SCHUYLER-SCOTT-SHELBY-STARK-TAZEWELL-VERMILION-WOODFORD- 301 PM CDT SUN AUG 16 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL ILLINOIS AND EAST CENTRAL ILLINOIS. .DAY ONE...TONIGHT THUNDERSTORM CHANCES WILL INCREASE INTO TONIGHT AS A SLOW MOVING FRONTAL BOUNDARY DRAWS CLOSER TO THE REGION. SEVERE STORMS ARE NOT EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY THE SLOW MOVING FRONTAL BOUNDARY AND A SERIES OF UPPER LEVEL DISTURBANCES WILL CONTINUE TO BRING PERIODIC CHANCES OF THUNDERSTORMS TO THE REGION FROM MONDAY INTO THURSDAY. A FEW SEVERE STORMS ARE POSSIBLE MONDAY AFTERNOON AND EVENING. DAMAGING WIND GUSTS AND HEAVY RAINFALL APPEAR TO THE PRIMARY SEVERE WEATHER THREATS AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED THROUGH TONIGHT. ILZ055>057-062-063-066>068-071>073-171100- CLARK-CLAY-COLES-CRAWFORD-CUMBERLAND-DOUGLAS-EDGAR-EFFINGHAM- JASPER-LAWRENCE-RICHLAND- 301 PM CDT SUN AUG 16 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST CENTRAL ILLINOIS AND SOUTHEAST ILLINOIS. .DAY ONE...TONIGHT THUNDERSTORM CHANCES WILL INCREASE INTO TONIGHT AS A SLOW MOVING FRONTAL BOUNDARY DRAWS CLOSER TO THE REGION. SEVERE STORMS ARE NOT EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY A SLOW MOVING FRONTAL BOUNDARY AND A SERIES OF UPPER LEVEL DISTURBANCES WILL BRING PERIODIC CHANCES OF THUNDERSTORMS TO THE REGION FROM MONDAY INTO THURSDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED THROUGH TONIGHT. HJS
The Lincoln radar (KILX), 97 km away, was scanning. The volume nearest the first event began at 21:57 UTC.
1 thunderstorm wind. Local standard time, as filed.
A few large tree branches were blown down onto power lines in Urbana. Approximately 3000 customers lost electricity.
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, 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: 192271.