Isolated supercell thunderstorms developed along an advancing warm front during the afternoon of May 1st. The storms produced 4 tornadoes across portions of Piatt, Champaign, and Vermilion counties.
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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.
Isolated supercell thunderstorms developed along an advancing warm front during the afternoon of May 1st. The storms produced 4 tornadoes across portions of Piatt, Champaign, and Vermilion counties. Only minor damage was noted.
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 1, 2:03 PM CST, 56 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 303 PM CDT TUE MAY 1 2012 .DISCUSSION... ISSUED 300 PM CDT TUE MAY 1 2012 A WET BIAS IS INDICATED IN ALL OF THE DETERMINISTIC MODELS AS A FRONTAL BOUNDARY LIFTS NORTH AS A WARM FRONT TONIGHT...THEN LINGERS JUST W-NW OF ILLINOIS FOR MUCH OF THE WEEK BEFORE RETURNING AS A COLD FRONT LATER IN THE WEEKEND. A WARM AND HUMID AIRMASS WILL DEVELOP OVER C IL TOMORROW BEHIND THE WARM FRONT. THAT SUMMER- TIME TYPE OF AIRMASS WILL BE RIPE FOR ANY UPPER SHORTWAVES AND LINGERING SURFACE BOUNDARIES TO BECOME ACTIVE WITH STORMS WHEN ANY ELEVATED MIXED LAYERS BECOME UNSTABLE ENOUGH FOR SUSTAINED UPDRAFTS. THE END RESULT IS AN ABUNDANCE OF PRECIP CHANCES PEPPERED THROUGHOUT THE NEXT 7 DAYS...BUT CONFIDENCE ON RAIN/STORM COVERAGE IN GENERAL IS LOW. SHORT TERM...TONIGHT THROUGH THURSDAY. THE WARM FRONT IS CURRENTLY EXTENDING FROM LOW PRESSURE NEAR FULTON COUNTY TO THE SE TOWARD TERRE HAUTE. AN MCV ASSOCIATED WITH THE SURFACE LOW WILL HELP TRIGGER ADDITIONAL SHOWERS AND A FEW STORMS ACROSS THE NORTH INTO THE EVENING. ADDITIONAL STORMS WILL BE POSSIBLE ACROSS THE SOUTH INTO THE EVENING AS THE SOUTHERN PERIPHERY OF THE MCV REMAINS ACTIVE WHERE SUNSHINE WAS MORE PLENTIFUL TODAY. WE KEPT SLIGHT CHANCE POPS IN ALL AREAS TONIGHT TO ACCOUNT FOR VARIOUS CONVECTIVE ELEMENTS THAT MAY FESTER UNDER THE ADVANCING WARM FRONT IN THE NORTH AND THE POST MCV AIRMASS IN THE SOUTH. IN OUR COUNTIES...WEDNESDAY SHOULD BE CAPPED WITH WARM AIR ALOFT FOR MOST OF THE DAY. OUR NORTHERN COUNTIES ARE IN THE DAY 2 SLIGHT RISK FOR SEVERE STORMS...CLOSER TO THE LINGERING WARM FRONT. THE HRRR MODEL IS SHOWING AN ADVANCING STORM COMPLEX LATER TONIGHT ACROSS MN/IA. THAT SYSTEM MAY PUT DOWN AN ADDITIONAL BOUNDARY FROM THE COLD POOL THAT DRIFTS EAST TOWARD IL WED MORNING. IT MAY BECOME ACTIVE AS PEAK HEATING CREATES SURFACE BASED INSTABILITY. EVEN IF MORNING CLOUDS AND FOG LINGER IN THAT AREA THROUGH THE MORNING...ANY EARLY AFTERNOON CLEARING WILL ALLOW FOR RAPID DESTABILIZATION OF THE AIRMASS IN FAR NW IL AND AREAS TO THE W-NW NEAR THE WARM FRONT. IF THE CAP BREAKS TO THE NW...THE STORMS MAY MAINTAIN SEVERE LEVELS INTO SOME OF OUR COUNTIES...BUT THE FARTHER E-SE THEY PROGRESS INTO THE CAPPED AIRMASS...THEY SHOULD LOSE SOME STRENGTH. THEREFORE WE ONLY HAVE SLIGHT CHANCE POPS IN OUR NORTHERN COUNTIES WED/WED NIGHT. THURSDAY MAY BE A SIMILAR SCENARIO TO WEDNESDAY...AS THE WARM FRONT/STATIONARY FRONT REMAINS IN PLACE TO OUR NW. OUR NW COUNTIES ARE IN THE DAY 3 SLIGHT RISK FOR SEVERE STORMS AGAIN AS A RESULT. NEAR RECORD HIGHS IN THE MID TO UPPER 80S ARE EXPECTED WED AND THUR AS DEWPOINTS CLIMB INTO THE MID 60S. IT WILL BE AN UNCOMFORTABLE AIRMASS AFTER THE RELATIVELY COOLER PORTIONS OF APRIL. LONG TERM...THURSDAY NIGHT THROUGH TUESDAY. STORM CHANCES WILL INCREASE FROM NW TO SE ON THURSDAY NIGHT AS LOW PRESSURE MOVES FROM THE DAKOTAS INTO THE GREAT LAKES...DRAGGING A COLD FRONT TOWARD NW IL. STORM CHANCES WILL CONTINUE FRI AND FRI NIGHT AS THE FRONT STALLS OUT ACROSS SOUTH CENTRAL IL. SATURDAY MAY SEE A BREAK IN THE ACTION BUT SLIGHT CHANCES WILL CONTINUE DUE TO THE PROXIMITY OF THE FRONT AND 500MB SHORTWAVES. HIGHER CHANCES OF SHOWERS AND STORMS WILL DEVELOP LATER SUNDAY INTO MONDAY AS THE NEXT LOW PRESSURE CENTER MOVES FROM THE CENTRAL PLAINS INTO C IL ALONG THE FRONT. A COOLER AIRMASS WILL TRY TO DROP SOUTH INTO OUR PORTION OF IL ON MONDAY NIGHT AND TUESDAY...AS HIGH PRESSURE FROM CANADA BUILDS SOUTHWARD. SO WE WENT WITH A COOLING TREND FOR MON AND TUES...WITH TUES HIGHS REMAINING IN THE 60S. SHIMON && .AVIATION... ISSUED 1254 PM CDT TUE MAY 1 2012 LOW-LEVEL CIRCULATION ASSOCIATED WITH OVERNIGHT/EARLY MORNING CONVECTIVE COMPLEX WILL LIFT NORTHWARD THROUGH THE ILLINOIS RIVER VALLEY THIS AFTERNOON. TO THE N/NW OF ITS TRACK...WINDS WILL REMAIN FROM THE EAST AT KPIA FOR THE NEXT COUPLE OF HOURS...THEN WILL BECOME LIGHT/VARIABLE AS THE FEATURE MOVES NEARBY. ELSEWHERE AROUND CENTRAL ILLINOIS...SOUTHEASTERLY WINDS WILL BECOME SOUTHERLY AS A WARM FRONT LIFTS NORTHWARD THROUGH THE AREA. HIGH RES MODELS SUCH AS THE HRRR SUGGEST WIDELY SCATTERED STORMS RE-DEVELOPING IN THE WARM SECTOR THIS AFTERNOON...HOWEVER CONFIDENCE IS TOO LOW TO INCLUDE IN FORECAST AT THIS TIME. FURTHER NORTHWEST IN CLOSER PROXIMITY TO THE CIRCULATION CENTER...RADAR LOOPS SUGGEST PERIODIC SHOWERS AT KPIA THROUGH ABOUT 21Z. PRECIP CHANCES DIMINISH AND SKIES BECOME PARTLY TO MOSTLY CLEAR ACROSS THE BOARD THIS EVENING...AS WARM FRONT PUSHES INTO NORTHERN ILLINOIS. DUE TO AMPLE LOW-LEVEL MOISTURE AND HUMID SOUTHERLY FLOW IN ITS WAKE...MAY SEE SOME FOG AT THE TERMINALS OVERNIGHT. WINDS OF AROUND 10KT WILL LIKELY PREVENT WIDESPREAD DENSE FOG...HOWEVER HAVE DROPPED VISBYS TO AROUND 3SM AFTER 09Z. ANY FOG WILL DISSIPATE BY EARLY WEDNESDAY MORNING...FOLLOWED BY MOSTLY CLEAR SKIES AND GUSTY S/SW WINDS. BARNES && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE LINCOLN IL 332 PM CDT TUE MAY 1 2012 ILZ027>031-036>038-040-041-021100- FULTON-KNOX-MARSHALL-MASON-MCLEAN-PEORIA-SCHUYLER-STARK-TAZEWELL- WOODFORD- 332 PM CDT TUE MAY 1 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL ILLINOIS. .DAY ONE...TONIGHT WIDELY SCATTERED THUNDERSTORMS WILL DEVELOP ALONG AN ADVANCING WARM FRONT THIS EVENING. WHILE SEVERE WEATHER IS NOT ANTICIPATED...A FEW OF THE STORMS COULD PRODUCING SMALL HAIL AND GUSTY WINDS. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY A NEARLY STATIONARY FRONTAL BOUNDARY WILL PRODUCE PERIODIC THUNDERSTORMS FROM THURSDAY THROUGH MONDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED THROUGH TONIGHT. ILZ042>057-061-021100- CASS-CHAMPAIGN-CHRISTIAN-COLES-DE WITT-DOUGLAS-EDGAR-LOGAN-MACON- MENARD-MORGAN-MOULTRIE-PIATT-SANGAMON-SCOTT-SHELBY-VERMILION- 332 PM CDT TUE MAY 1 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL ILLINOIS AND EAST CENTRAL ILLINOIS. .DAY ONE...TONIGHT WIDELY SCATTERED THUNDERSTORMS WILL DEVELOP ALONG AN ADVANCING WARM FRONT THIS EVENING. WHILE SEVERE WEATHER IS NOT ANTICIPATED...A FEW OF THE STORMS COULD PRODUCING SMALL HAIL AND GUSTY WINDS. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY AN APPROACHING COLD FRONT WILL BECOME NEARLY STATIONARY ACROSS THE REGION BY THIS WEEKEND...PRODUCING PERIODIC THUNDERSTORMS FROM THURSDAY NIGHT THROUGH MONDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED THROUGH TONIGHT. ILZ062-063-066>068-071>073-021100- CLARK-CLAY-CRAWFORD-CUMBERLAND-EFFINGHAM-JASPER-LAWRENCE-RICHLAND- 332 PM CDT TUE MAY 1 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST CENTRAL ILLINOIS AND SOUTHEAST ILLINOIS. .DAY ONE...TONIGHT WIDELY SCATTERED THUNDERSTORMS WILL DEVELOP ALONG AN ADVANCING WARM FRONT THIS EVENING. WHILE SEVERE WEATHER IS NOT ANTICIPATED...A FEW OF THE STORMS COULD PRODUCING SMALL HAIL AND GUSTY WINDS. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY AN APPROACHING COLD FRONT WILL BECOME NEARLY STATIONARY ACROSS THE REGION BY THIS WEEKEND...PRODUCING PERIODIC THUNDERSTORMS FROM FRIDAY THROUGH MONDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED THROUGH TONIGHT. BARNES
The Lincoln radar (KILX), 74 km away, was scanning. The volume nearest the first event began at 20:59 UTC.
4 tornado, 4 hail. Local standard time, as filed.
A tornado briefly touched down in a field southeast of Monticello. No damage was reported.
A tornado touched down about 3.5 miles northeast of Ivesdale at 4:06 PM CDT then tracked northeastward for 8 miles before lifting 2 miles west of Willard Airport at 4:17 PM CDT. The tornado damaged the roof and windows of a house, overturned a trailer, damaged a corn crib and chicken coop, and knocked down 6 trees along its path.
A tornado briefly touched down in a field west of Sidney. No damage was reported.
A tornado touched down just southeast of Tilton at 4:18 PM CDT. The tornado blew a small carport garage about 75 yards onto a trailer before lifting at 4:19 PM CDT.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2012Every state in 2012This day in weather historyThe tornado archive for Illinois, 2012Warnings in Illinois, May 2012
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: 371646, 371650, 371653, 371651, 371654, 371652, 371655, 371656.