S. produced an extended period of hot and humid weather across central Illinois.
Every event with a place to put it; 27 filed by county or forecast zone are drawn at its center, in a lighter ring. 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 ILX wrote it up.
A large upper-level ridge of high pressure over the southern U.S. produced an extended period of hot and humid weather across central Illinois. With actual air temperatures well into the 90s and dewpoints in the upper 70s...heat index readings soared above 105 degrees....with the highest values noted along and south of a Rushville...to Lincoln...to Danville line.
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 3, 11:54 AM CST, 6 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1254 PM CDT TUE AUG 3 2010 .DISCUSSION... ISSUED 1023 AM CDT TUE AUG 3 2010 MAIN WEATHER STORY TODAY WILL BE THE HEAT AND HUMIDITY...AS AFTERNOON HIGH TEMPERATURES SOAR INTO THE 90S. EARLY MORNING COMPLEX OF THUNDERSTORMS THAT TRACKED ACROSS NORTHERN ILLINOIS HAS SENT AN OUTFLOW BOUNDARY ALL THE WAY SOUTH TO NEAR THE I-64 CORRIDOR...HOWEVER EXPECT THIS VERY SHALLOW BOUNDARY TO READILY MIX OUT TODAY. HIGHLY CAPPED AIRMASS ACROSS KANSAS/MISSOURI WILL SPREAD NORTHEASTWARD INTO THE AREA...WITH UPSTREAM 12Z 700MB TEMPS IN THE 13-14C RANGE. THIS LAYER OF WARM AIR ALOFT WILL SERVE TO SUPPRESS ADDITIONAL CONVECTIVE DEVELOPMENT ACROSS MUCH OF CENTRAL ILLINOIS...EXCEPT PERHAPS ALONG AND NORTH OF I-74 WHERE A FEW SHOWERS/STORMS MAY DEVELOP IN CLOSER PROXIMITY TO STATIONARY FRONTAL BOUNDARY DRAPED ACROSS NORTHERN ILLINOIS. DROPPED POPS ENTIRELY ACROSS THE CENTRAL AND SOUTHERN ZONES...AND MAINTAINED JUST LOW CHANCES ACROSS THE NORTH. ALSO ADJUSTED TEMPS UP A DEGREE OR TWO...WITH LOWER TO MIDDLE 90S ACROSS THE BOARD. COULD EVEN SEE A FEW UPPER 90S ALONG AND SOUTH OF A JACKSONVILLE TO EFFINGHAM LINE. HEAT ADVISORY REMAINS IN EFFECT FOR THE ENTIRE AREA THIS AFTERNOON. && .AVIATION... ISSUED 1254 PM CDT TUE AUG 3 2010 MOSTLY CLEAR SKIES WILL PREVAIL ACROSS CENTRAL ILLINOIS THIS AFTERNOON AND EVENING...AS VERY WARM AIR ALOFT KEEPS THE ATMOSPHERE CAPPED. AN UPPER-LEVEL DISTURBANCE IS EXPECTED TO TRIGGER CLUSTERS OF THUNDERSTORMS ALONG A NEARLY STATIONARY FRONTAL BOUNDARY EXTENDING FROM CENTRAL IOWA INTO NORTHERN ILLINOIS LATE TONIGHT. MOST OF THE CONVECTION SHOULD REMAIN NORTH OF THE TAF SITES...HOWEVER STORMS MAY COME CLOSE ENOUGH TO KPIA AND KBMI TO WARRANT A VCTS AFTER 07Z. WINDS WILL INITIALLY BE SOUTHERLY AT 5 TO 10 KT THIS AFTERNOON...THEN WILL BECOME LIGHT/VARIABLE TONIGHT INTO WEDNESDAY MORNING. BARNES && .PREV DISCUSSION... ISSUED 328 AM CDT TUE AUG 3 2010 SHORT TERM...TODAY AND TOMORROW... MCS MOVING ACROSS N IL THIS MORNING LOSING A LOT OF THE SERN PROPAGATION THAT WAS PREVIOUSLY EXPECTED. THAT BEING SAID...STILL EXPECTING PRECIP FOR MUCH OF THE NRN HALF OF THE CWA THIS MORNING...BREAKING UP MIDDAY AND ALLOWING A RAPID REBOUND OF TEMPS ACROSS THE FA. HEAT ADVISORY IS IN EFFECT CWA WIDE WITH TEMPS INTO THE MID TO UPPER 90S AFTER THE CLOUDS CLEAR...AND IN CONCERT WITH PLENTY OF LLVL MOISTURE...THE HEAT INDICES CLIMB INTO THE MID 100S FOR THE SRN HALF OF THE STATE. TEMPS NOT REALLY EXPECTED TO GIVE MUCH OF A BREAK TOMORROW...BUT ALSO VERY CLOUD DEPENDENT WITH MODELS/CURRENT SAT IMAGERY HINTING AT ANOTHER POSSIBLE MCS MOVING ACROSS THE NRN PORTION OF THE STATE. FORECAST CONFIDENCE IS RATHER LOW WITH THESE SYSTEMS RIDING ALONG THE SRN EDGE OF THE 500MB HEIGHT GRADIENT AND A LOT OF THE SMALL WAVES ARE NOT GETTING REPRESENTED ACCURATELY. LONG TERM...THURSDAY THROUGH SATURDAY... SLIGHT POPS IN FOR THURSDAY EARLY AS THE BOUNDARIES FROM ANY OF THE SYSTEMS FOR TUES AND WED CREATING SOME UNCERTAINTY FOR THE POP FORECAST WITH SUCH A HOT AND HUMID AIR MASS. TROF DIGGING IN TO THE NORTH TRYING TO PUSH SOME OF THE HOT AIR FURTHER SOUTH HOWEVER...AND 850MB TEMPS COOL ABOUT 10C FROM TUESDAY AFTERNOON TO FRIDAY AFTERNOON...GETTING SOME RELIEF FROM THE MID TO UPPER 90S FOR FRIDAY AND SATURDAY. HJS && .ILX WATCHES/WARNINGS/ADVISORIES... EXCESSIVE HEAT WARNING UNTIL 7 PM CDT THIS EVENING FOR ILZ036- 040>042-047>057-061>063-066>068-071>073. HEAT ADVISORY UNTIL 7 PM CDT WEDNESDAY FOR ILZ027>031-036>038- 040>057-061>063-066>068-071>073. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE LINCOLN IL 1200 PM CDT TUE AUG 3 2010 ILZ027>031-036>038-043>046-041100- CHAMPAIGN-DE WITT-FULTON-KNOX-MARSHALL-MCLEAN-PEORIA-PIATT-STARK- TAZEWELL-VERMILION-WOODFORD- 1200 PM CDT TUE AUG 3 2010 ...HEAT ADVISORY IN EFFECT UNTIL 7 PM CDT WEDNESDAY... THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL ILLINOIS AND EAST CENTRAL ILLINOIS. .DAY ONE...THIS AFTERNOON AND TONIGHT HOT AND VERY HUMID CONDITIONS WILL PREVAIL TODAY. AFTERNOON HEAT INDICES ARE EXPECTED TO RANGE FROM 100 TO 105 DEGREES. ISOLATED THUNDERSTORMS ARE POSSIBLE ALONG AND NORTH OF I-74 THIS AFTERNOON...NEAR A STATIONARY FRONTAL BOUNDARY DRAPED ACROSS NORTHERN ILLINOIS. ADDITIONAL THUNDERSTORMS MAY DEVELOP ALONG THE FRONT LATER TONIGHT...AS AN UPPER-LEVEL DISTURBANCE TRACKS THROUGH THE AREA. FREQUENT LIGHTNING...GUSTY WINDS...AND LOCALLY HEAVY RAINFALL WILL BE POSSIBLE WITH THE STORMS TONIGHT. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY HOT AND HUMID CONDITIONS WILL CONTINUE INTO WEDNESDAY...WITH AFTERNOON HEAT INDICES ONCE AGAIN RISING ABOVE THE 100 DEGREE MARK. PERIODS OF THUNDERSTORMS WILL OCCUR WEDNESDAY AND WEDNESDAY NIGHT...AS A COLD FRONT DROPS SLOWLY SOUTHWARD THROUGH THE REGION. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED AFTER MIDNIGHT TONIGHT. ILZ040>042-047>057-061>063-041100- CASS-CHRISTIAN-CLARK-COLES-CUMBERLAND-DOUGLAS-EDGAR-LOGAN-MACON- MASON-MENARD-MORGAN-MOULTRIE-SANGAMON-SCHUYLER-SCOTT-SHELBY- 1200 PM CDT TUE AUG 3 2010 ...HEAT ADVISORY IN EFFECT UNTIL 7 PM CDT WEDNESDAY... THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL ILLINOIS AND EAST CENTRAL ILLINOIS. .DAY ONE...THIS AFTERNOON AND TONIGHT HOT AND VERY HUMID CONDITIONS WILL PREVAIL TODAY. AFTERNOON HEAT INDICES ARE EXPECTED TO RANGE FROM 102 TO 107 DEGREES. SCATTERED THUNDERSTORMS MAY DEVELOP LATE TONIGHT...AS AN UPPER-LEVEL DISTURBANCE TRACKS THROUGH THE AREA. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY HOT AND HUMID CONDITIONS WILL CONTINUE INTO WEDNESDAY...WITH AFTERNOON HEAT INDICES ONCE AGAIN RISING ABOVE THE 100 DEGREE MARK. PERIODS OF THUNDERSTORMS WILL OCCUR WEDNESDAY AND THURSDAY...AS A COLD FRONT DROPS SLOWLY SOUTHWARD THROUGH THE REGION. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED THROUGH TONIGHT. ILZ066>068-071>073-041100- CLAY-CRAWFORD-EFFINGHAM-JASPER-LAWRENCE-RICHLAND- 1200 PM CDT TUE AUG 3 2010 ...HEAT ADVISORY IN EFFECT UNTIL 7 PM CDT WEDNESDAY... THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST ILLINOIS. .DAY ONE...THIS AFTERNOON AND TONIGHT HOT AND VERY HUMID CONDITIONS WILL PREVAIL TODAY. AFTERNOON HEAT INDICES ARE EXPECTED TO RANGE FROM 105 TO 110 DEGREES. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY HOT AND VERY HUMID CONDITIONS WILL DEVELOP AGAIN ON WEDNESDAY. AFTERNOON HEAT INDICES ARE EXPECTED TO RANGE FROM 105 TO 110 DEGREES. THERE WILL BE A CHANCE FOR THUNDERSTORMS ON WEDNESDAY AND THURSDAY...AS A FRONTAL BOUNDARY SINKS SLOWLY SOUTHWARD THROUGH THE REGION. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED THROUGH TONIGHT. BARNES
The national radar mosaic for the moment the first event began.
27 excessive heat. Local standard time, as filed.
Heat index readings exceeded 105 degrees across Cass County on August 3rd and 4th.
Heat index readings exceeded 105 degrees across Schuyler County on August 3rd and 4th.
Heat index readings exceeded 105 degrees across Scott County on August 3rd and 4th.
Heat index readings exceeded 105 degrees across Morgan County on August 3rd and 4th.
Heat index readings exceeded 105 degrees across Mason County on August 3rd and 4th.
Heat index readings exceeded 105 degrees across Menard County on August 3rd and 4th.
Heat index readings exceeded 105 degrees across Sangamon County on August 3rd and 4th.
Heat index readings exceeded 105 degrees across Logan County on August 3rd and 4th.
Heat index readings exceeded 105 degrees across DeWitt County on August 3rd and 4th.
Heat index readings exceeded 105 degrees across Macon County on August 3rd and 4th.
Heat index readings exceeded 105 degrees across Christian County on August 3rd and 4th.
Heat index readings exceeded 105 degrees across Shelby County on August 3rd and 4th.
Heat index readings exceeded 105 degrees across Moultrie County on August 3rd and 4th.
Heat index readings exceeded 105 degrees across Piatt County on August 3rd and 4th.
Heat index readings exceeded 105 degrees across Champaign County on August 3rd and 4th.
Heat index readings exceeded 105 degrees across Vermilion County on August 3rd and 4th.
Heat index readings exceeded 105 degrees across Douglas County on August 3rd and 4th.
Heat index readings exceeded 105 degrees across Coles County on August 3rd and 4th.
Heat index readings exceeded 105 degrees across Edgar County on August 3rd and 4th.
Heat index readings exceeded 105 degrees across Cumberland County on August 3rd and 4th.
Heat index readings exceeded 105 degrees across Clark County on August 3rd and 4th.
Heat index readings exceeded 105 degrees across Effingham County on August 3rd and 4th.
Heat index readings exceeded 105 degrees across Jasper County on August 3rd and 4th.
Heat index readings exceeded 105 degrees across Crawford County on August 3rd and 4th.
Heat index readings exceeded 105 degrees across Clay County on August 3rd and 4th.
Heat index readings exceeded 105 degrees across Richland County on August 3rd and 4th.
Heat index readings exceeded 105 degrees across Lawrence County on August 3rd and 4th.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2010Every state in 2010This day in weather historyWarnings in Illinois, August 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: 258129, 258130, 258131, 258132, 258133, 258134, 258135, 258136, 258137, 258138, 258139, 258140, 258141, 258142, 258143, 258144, 258145, 258146, 258147, 258148, 258149, 258150, 258151, 258152, 258153, 258154, 258155.