A low pressure system tracked from Missouri across central Illinois on May 21st, triggering scattered strong to severe thunderstorms along and east of I-57. Enough wind shear was present near the track of the low to create supercell thunderstorms with large hail, damaging winds and areas of flash flooding.
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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.
A low pressure system tracked from Missouri across central Illinois on May 21st, triggering scattered strong to severe thunderstorms along and east of I-57. Enough wind shear was present near the track of the low to create supercell thunderstorms with large hail, damaging winds and areas of flash flooding. In addition...two brief tornado touchdowns were reported in Edgar County as the storms tracked further eastward toward Indiana.
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 May 21, 11:15 AM CST, 5 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1215 PM CDT FRI MAY 21 2010 .DISCUSSION... ISSUED 1030 AM CDT FRI MAY 21 2010 VERTICALLY STACKED LOW PRESSURE NOW LOCATED NEAR RUSHVILLE AND IS MOVING SLOWLY EASTWARD. OBJECTIVE ANALYSES SHOW INSTABILITY AXIS TO THE EAST OF THE LOW EXTENDING FROM SPRINGFIELD SOUTHWARD INTO SOUTHERN ILLINOIS...WITH MUCAPES 500-1000 J/KG. EXTENSIVE CLOUD COVER IS RESTRICTING INSOLATION AND FURTHER DESTABILIZATION. HOWEVER...MID LVL COOL POOL ASSOCIATED WITH UPPER LOW AND DEEP CYCLONIC FLOW MAY PROVIDE JUST ENOUGH SUPPORT FOR ISOLATED SEVERE STORMS OVER EASTERN ILLINOIS THIS AFTERNOON. EXPECT MARGINALLY SEVERE HAIL AND POSSIBLY AN ISOLATED TORNADO DURING A NARROW WINDOW OF OPPORTUNITY BEFORE STORMS MOVE INTO INDIANA. ELSEWHERE...SCATTERED SHOWERS AND ISOLATED STORMS WILL CONTINUE TO DEVELOP FROM TIME TO TIME ALMOST ANYWHERE WITHIN THE UNCAPPED AIRMASS. HIGHEST COVERAGE OF PRECIPITATION HAS BEEN ASSOCIATED WITH VORT LOBE NOW MOVING INTO INDIANA. A WEAKER SHORTWAVE IS NOW ENTERING WESTERN ILLINOIS ON THE SOUTHERN PERIPHERY OF THE UPPER LOW AND THIS FEATURE MAY PROMOTE AN UPSWING IN SHOWERS LATER THIS MORNING AND AFTERNOON BEFORE SURFACE TROUGH MOVES EASTWARD BRINGING WEAK SYNOPTIC-SCALE SUBSIDENCE. THE EARLY MORNING FORECAST PACKAGE CAPTURES THIS SCENERIO AND ANY UPCOMING UPDATES WILL BE MINOR. 04 && .AVIATION... ISSUED 1217 PM CDT FRI MAY 21 2010 SFC/UPR STACKED LOW JUST W PIA WL MOVE EWD INTO IND 00Z-03Z. DEEP CYCLONIC FLOW AND MSTR ARE PROVIDING MOSTLY VFR/MVFR CLDS OVR THE AREA ALG WITH SCT CNVCTN. THE STRONGEST/MOST NUMRS STMS WIL BE JUST E OF CMI...WITH THE CNTL IL TAF SITES WITHIN THE MORE WIDELY SCT ACTVTY. WL HV VCTS FOR THE TERMINALS THIS AFTN WITH A TEMPO FOR THUNDER AT CMI. CDFNT EXTDG S OF SFC LOW WL SWEEP THRU THE ENTIRE AREA BY 23Z...TURNING WNDS TO WLY AND BRINGING A TEMPORARY PD OF WRAP-AROUND LOW CLDS. THE CLDS SHOULD MOVE E OF THE AREA BEFORE 06Z...HOWEVER RESIDUAL LOW LEVEL MSTR WILL COMBINE WITH LGT WNDS AND RADIATIONAL COOLING TO PRODUCE AREAS OF FOG. VSBYS MAY GO BELOW A MILE AT PIA/BMI/CMI 08Z-12Z...WITH 2 MI OR SO FOR SPI/DEC. THE FOG WL DIMINISH BY 15Z SAT. 04 && .PREV DISCUSSION... ISSUED 330 AM CDT FRI MAY 21 2010 00Z SHORT RANGE MODELS ARE IN FAIR AGREEMENT INTO THIS WEEKEND. ONE MORE DAY OF SHOWERS AND A FEW THUNDERSTORMS TODAY AS LOW PRESSURE OVER NORTHERN MO MOVES INTO NORTHERN IL BY SUNSET PULLING A COLD FRONT EAST ACROSS IL TODAY. A DRIER/SUNNIER AND MUCH WARMER SUMMERLIKE PATTERN TAKES SHAPE THIS WEEKEND THROUGH NEXT WORK WEEK WITH THE WARMEST STRETCH OF WEATHER EXPECTED SO FAR THIS SEASON. SHORT TERM...TODAY THROUGH MONDAY NIGHT. JUST A FEW SPOTTY LIGHT SHOWERS AND DRIZZLE OVER CENTRAL/SE IL MOST OF THE NIGHT. MAIN AREA OF SHOWERS HAS LIFTED NE OF CENTRAL IL INTO SE WI...FAR NE IL...SOUTHERN LAKE MI AND NE INDIANA. A BAND OF SHOWERS EXTENDED FROM SE IA INTO NE MO...SW WILL WITH A FEW THUNDERSTORMS EAST AND SOUTH OF ST LOUIS...AND MOVING INTO SW IL. EARLY MORNING SURFACE MAP SHOWS 1008 MB LOW PRESSURE OVER NORTHERN MO WITH ITS COLD FRONT THROUGH CENTRAL MO INTO NW AR AND NORTH TX. ITS WARM FRONT WAS OVER FAR SOUTHERN IL INTO SW KY AND MIDDLE TN. ALOFT A 566 DM 500 MB LOW WAS SPINNING NEAR THE IA/MO BORDER. LOW CLOUDS KEEPING TEMPS NEARLY STEADY EARLY THIS MORNING IN CENTRAL/SE IL WITH READINGS IN LOWER 60S AND MOIST DEWPOINTS IN THE UPPER 50S TO AROUND 60F. SE WINDS ARE LESS THAN 10 MPH. MODELS MOVE LOW PRESSURE NE FROM NORTHERN MO INTO NORTHERN IL BY 00Z/7 PM WHILE BRING THE COLD FRONT EAST ACROSS IL. STRONG NEGATIVE TITLED UPPER LEVEL TROF MOVES EAST FROM IA/MO ACROSS IL TOWARD INDIANA BY SUNSET. THIS TO KEEP HIGH CHANCES OF SHOWERS TODAY ESPECIALLY OVER NORTHERN AND EASTERN AREAS. BEST CHANCES OF A FEW THUNDERSTORMS WILL BE SE OF I-55. SPC HAS SLIGHT RISK OF SEVERE STORMS THIS AFTERNOON IN FAR EASTERN IL (EAST OF I-57) INTO INDIANA. CAPES PEAK FROM 1000-1400 J/KG EAST OF I-57 THIS AFTERNOON WITH HIGHEST CAPES/INSTABILITY ALONG AND EAST OF THE WABASH RIVER. AREAS FROM DANVILLE TO OLNEY EAST HAVE 15% RISK OF HAIL AND GUSTY WINDS THIS AFTERNOON. WIND SHEAR IS FAIRLY WEAK SO JUST 2% RISK OF TORNADOES. PRECIPITABLE WATER VALUES PEAK FROM 1.25 TO 1.5 INCHES TODAY SO SHOWERS COULD PRODUCE LOCALLY HEAVY RAINS IN EASTERN IL. HAVE BETWEEN A QUARTER AND HALF INCH OF ADDITIONAL RAIN EXPECTED BY EARLY EVENING WITH ISOLATED TO SCATTERED SHOWERS LINGERING IN EASTERN IL THIS EVENING MAINLY BEFORE 9 PM. LEANED ON THE COOL SIDE OF GUIDANCE FOR HIGHS TODAY RANGING FROM THE UPPER 60S TO NEAR 70F FROM I-55 NW TO THE MID 70S IN FAR SE IL NEAR THE WABASH RIVER. MODELS TRENDING A BIT QUICKER EXITING THE UPPER LEVEL TROF EAST ACROSS THE OHIO VALLEY TONIGHT WITH CLEARING COMING IN A BIT QUICKER AS WELL WITH LIGHT WEST WINDS. THIS SHOULD ALLOW PATCHY FOG TO DEVELOP OVERNIGHT OVER CENTRAL IL AS TEMPS COOL TOWARD DEWPOINTS IN THE MID TO UPPER 50S. SAT LOOKS LIKE A NICE DAY AS STRONG UPPER LEVEL RIDGE BUILDS INTO THE MS VALLEY SAT BRINGING MOSTLY SUNNY SKIES AND START OF A WARMER UP. HIGHS IN THE LOWER 80S MOST AREAS WITH EAST CENTRAL IL NEAR 80F. LOWS SAT NIGHT IN THE LOW TO MID 60S. EVEN WARMER ON SUNDAY AND MONDAY AS 850 MB TEMPS ELEVATE BETWEEN 18-20C AND 925 MB TEMPS AROUND 25C. HAVE HIGHS IN THE UPPER 80S TO NEAR 90F. CURULE SHOWS FEW TO SCATTERED CUMULUS CLOUDS SUNDAY AFTERNOON MAINLY IN EASTERN IL EAST OF I-57. LONG TERM...TUESDAY THROUGH FRIDAY. STRONG UPPER LEVEL RIDGE ANCHORED OVER THE GREAT LAKES INCLUDING IL WHICH RETROGRADES WESTWARD INTO THE GREAT PLAINS LATE NEXT WEEK. EXPECT ABOVE NORMAL TEMPERATURES TO CONTINUE THROUGH FRIDAY WITH HIGHS IN THE MID TO UPPER 80S AND GENERALLY DRY CONDITIONS WITH PARTLY TO MOSTLY SUNNY SKIES. COULD BE VERY ISOLATED THUNDERSTORMS DURING THE AFTERNOON HOURS FROM DAYTIME HEATING/INSTABILITY BUT MOST AREAS SHOULD REMAIN DRY NEXT WORK WEEK. HUETTL && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE LINCOLN IL 1044 AM CDT FRI MAY 21 2010 ILZ045-046-055>057-062-063-067-068-072-073-221100- CHAMPAIGN-CLARK-COLES-CRAWFORD-CUMBERLAND-DOUGLAS-EDGAR-JASPER- LAWRENCE-RICHLAND-VERMILION- 1044 AM CDT FRI MAY 21 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST CENTRAL ILLINOIS AND SOUTHEAST ILLINOIS. .DAY ONE...TODAY AND TONIGHT THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS BEGINNING AROUND MIDDAY ALONG AND TO THE EAST OF INTERSTATE 57. THE MAIN THREATS WILL BE LARGE HAIL...AND PERHAPS AN ISOLATED WEAK TORNADO. A LOW PRESSURE AREA IS LOCATED OVER WESTERN ILLINOIS WITH A COLD FRONT EXTENDING SOUTHWARD BASICALLY ALONG THE MISSISSIPPI RIVER. THE STORMS WILL DEVELOP AHEAD OF THIS FRONT AROUND MIDDAY...WITH THE STORMS THEN MOVING INTO INDIANA BEFORE EVENING. THE OVERALL SEVERE WEATHER THREAT WILL END WITH THE COLD FRONTAL PASSAGE LATER THIS AFTERNOON. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED FROM MIDDAY INTO THE AFTERNOON HOURS. ILZ071-221100- CLAY- 1044 AM CDT FRI MAY 21 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST ILLINOIS. .DAY ONE...TODAY AND TONIGHT THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON. THE MAIN THREATS WILL BE LARGE HAIL...AND PERHAPS AN ISOLATED WEAK TORNADO. A LOW PRESSURE AREA IS LOCATED OVER WESTERN ILLINOIS WITH A COLD FRONT EXTENDING SOUTHWARD BASICALLY ALONG THE MISSISSIPPI RIVER. THE STORMS WILL DEVELOP AHEAD OF THIS FRONT AROUND MIDDAY...WITH THE STORMS THEN MOVING INTO INDIANA BEFORE EVENING. THE OVERALL SEVERE WEATHER THREAT WILL END WITH THE COLD FRONTAL PASSAGE AROUND 6 PM. THE LITTLE WABASH RIVER AT CLAY CITY IS EXPECTED TO FALL BELOW FLOOD STAGE TOMORROW AFTERNOON. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED FROM MIDDAY INTO THE AFTERNOON HOURS. ILZ029-036-037-040-041-047-049-050-221100- CASS-FULTON-MASON-MORGAN-PEORIA-SCHUYLER-SCOTT-TAZEWELL- 1044 AM CDT FRI MAY 21 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL ILLINOIS. .DAY ONE...TODAY AND TONIGHT ISOLATED THUNDERSTORMS WILL BE POSSIBLE THROUGH EARLY AFTERNOON AS A COLD FRONT PASSES THROUGH THE AREA. NO SEVERE WEATHER IS EXPECTED AT THIS TIME. THE ILLINOIS RIVER FROM PEORIA DOWNSTREAM WILL REMAIN IN FLOOD FOR THE NEXT SEVERAL DAYS. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED THROUGH TONIGHT. ILZ027-028-030-031-038-042>044-048-051>054-061-066-221100- CHRISTIAN-DE WITT-EFFINGHAM-KNOX-LOGAN-MACON-MARSHALL-MCLEAN- MENARD-MOULTRIE-PIATT-SANGAMON-SHELBY-STARK-WOODFORD- 1044 AM CDT FRI MAY 21 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL ILLINOIS AND SOUTHEAST ILLINOIS. .DAY ONE...TODAY AND TONIGHT ISOLATED THUNDERSTORMS WILL BE POSSIBLE THROUGH MID AFTERNOON AS A COLD FRONT PASSES THROUGH THE AREA. NO SEVERE WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED THROUGH TONIGHT. CHURCHILL
The Lincoln radar (KILX), 132 km away, was scanning. The volume nearest the first event began at 17:19 UTC.
5 flash flood, 5 hail, 2 tornado, 1 thunderstorm wind. Local standard time, as filed.
A tornado briefly touched down 1 mile south of Hume. No damage was reported.
A tornado briefly touched down northeast of Metcalf. No damage was reported.
Heavy rainfall with rates of 2.00 to 2.50 inches per hours produced flash flooding in a narrow stretch of northern Clark County. Most roads were inundated with water including U.S. Route 40 in Martinsville where there was 2 feet of standing water. In Marshall, 3.00 to 4.00 inches of rain fell in about 90 minutes which flooded most roads in the town.
Training thunderstorm cells produced an area of flash flooding in northwest Edgar County. Rainfall rates of nearly 2.00 inches per hour were reported. Many rural roads were inundated by the flooding, particularly between the towns of Hume and Metcalf.
A few trees were blown down south of Chauncey.
Training thunderstorm cells produced an area of flash flooding in southwest Vermilion County. Rainfall rates of nearly 2.00 inches per hour were reported. Many rural roads were inundated because of the flooding, particularly near Indianola.
Training thunderstorm cells produced an area of flash flooding in northeast Champaign County. Rainfall rates of nearly 1.50 inches per hour for more than three hours were reported. Many rural roads were inundated by the flooding, particularly U.S. Route 136 east of Gifford.
Training thunderstorm cells produced an area of flash flooding in northwest Vermilion County. Rainfall rates of 1.50 inches per hour for nearly 2.5 hours were reported. Many roads were inundated, particularly Illinois Route 49 and U.S. Route 136 west of Potomac.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2010Every state in 2010This day in weather historyThe tornado archive for Illinois, 2010Warnings in Illinois, May 2010
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: 227255, 227256, 237465, 227249, 227250, 227251, 227252, 237468, 227254, 227253, 237473, 237478, 237482.