A vigorous upper-level disturbance interacting with an approaching cold front triggered scattered severe thunderstorms across north-central Illinois during the afternoon and early evening of August 9th. to Paris line.
Every event with a place to put it. 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 vigorous upper-level disturbance interacting with an approaching cold front triggered scattered severe thunderstorms across north-central Illinois during the afternoon and early evening of August 9th. Most of the storms impacted locations along and north of a Peoria...to Bloomington...to Paris line. Downburst winds of 70 to 80 mph produced extensive damage across McLean County from near Danvers to just north of Heyworth. Other cells produced widespread wind damage across Champaign and Edgar counties. In addition to the wind damage, large hail up to the size of half dollars was reported north of Heyworth in McLean County.
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 9, 11:42 AM CST, 2 hours 23 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1242 PM CDT THU AUG 9 2012 .DISCUSSION... ISSUED 1036 AM CDT THU AUG 9 2012 AT 10 AM A POORLY DEFINED TROUGH OF LOW PRESSURE STRETCHED FROM EASTERN MO ACROSS IL AND INTO INDIANA. AT MID LEVELS A STRONG AND COMPACT CLOSED CIRCULATION WAS DIVING SOUTH INTO NORTHERN WI IN STEEP NORTHERLY FLOW. EXPECT SCATTERED STORMS TO RE-DEVELOP ACROSS THE CWA THIS AFTERNOON AS LIFT INCREASES AHEAD OF THE SHORTWAVE. DUE TO THE LACK OF A FOCUSING MECHANISM AND MODEST INSTABILITY/SHEAR...THINK SEVERE THREAT WILL BE LOW BUT BEST CHANCES EAST OF I-57 WHERE BETTER UPPER DYNAMICS OVERLAP WITH HIGHER INSTABILITY AND SFC TROUGH SHIFTING EAST THIS AFTERNOON. BY MID AFTERNOON INCREASING NORTHERLY FLOW BEHIND THE SFC TROUGH BRINGS IN COLD ADVECTION TO THE WESTERN CWA WHERE HIGHS ARE LIMITED TO THE LOWER 80S. HIGHS NEAR 90 POSSIBLE FOR THE SOUTHEAST THIRD WHERE LIGHT SOUTH WINDS PERSIST LONGEST. && .AVIATION... ISSUED 1242 PM CDT THU AUG 9 2012 A TROUGH OF LOW PRESSURE WILL TRACK SOUTHEAST THROUGH CENTRAL IL THIS AFTERNOON...WITH SOUTH-SOUTHWEST FLOW AHEAD OF THE TROUGH SHIFTING TO NORTHWEST BEHIND IT. POTENTIAL STILL THERE FOR SCATTERED THUNDERSTORMS EVEN BEHIND THE TROUGH...AS AN UPPER LEVEL DISTURBANCE DROPPING SOUTH FROM WISCONSIN INTERACTS WITH LINGERING INSTABILITY. NOT TOO CONFIDENT IN STORM COVERAGE/LOCATION SO WILL HAVE VCTS IN FOR ALL SITES THROUGH EARLY EVENING. ANY STORM WOULD HAVE BRIEF VSBY REDUCTIONS IN HEAVY RAIN AND VARIABLE/GUSTY WINDS. AFTER THE TROUGH SHIFTS EAST OF THE AREA 10-15 KT NORTHERLY WINDS LOCK IN AND CONTINUE THROUGH MUCH OF FRIDAY. MVFR CEILINGS CURRENTLY IN CENTRAL WISCONSIN WILL ROTATE SOUTH WITH THE ASSOCIATED UPPER TROUGH...AND AFFECT TAF SITES OVERNIGHT. FORECAST SOUNDINGS SHOW CEILINGS LOWERING TO AROUND 1 KFT AGL AFTER MIDNIGHT THROUGH 13-14Z AND THIS SEEMS REASONABLE GIVEN HIGH SFC-1KM RH BENEATH STRONG CYCLONIC FLOW ALOFT. WILL BANK ON BRISK WINDS KEEPING VSBYS ABOVE 6SM. 25 && .PREV DISCUSSION... ISSUED 305 AM CDT THU AUG 9 2012 SHORT TERM...TODAY THROUGH SATURDAY MAIN CHALLENGE WITH THIS FORECAST PACKAGE WILL BE POPS IN THE SHORT-TERM...AS LOW PRESSURE TRACKS ACROSS SOUTH-CENTRAL ILLINOIS TODAY. MODELS CONTINUE TO PERFORM POORLY...WITH NONE OF THE 00Z RUNS PORTRAYING AN ACCURATE PICTURE OF THE CURRENT SITUATION. GIVEN UNRELIABLE OPERATIONAL MODELS...WILL HAVE TO RELY ON OBSERVATIONAL TRENDS AND CONCEPTUAL MODELS FOR THE FORECAST OVER THE NEXT 24 HOURS. 06Z SURFACE CHART SHOWS STATIONARY FRONTAL BOUNDARY EXTENDING FROM THE OHIO RIVER VALLEY INTO THE CENTRAL PLAINS...WITH LOW PRESSURE CENTERED OVER EASTERN KANSAS. THIS LOW IS EXPECTED TO TRACK E/NE TODAY...EVENTUALLY REACHING SOUTH-CENTRAL INDIANA BY EVENING. ALOFT...INITIAL SHORT-WAVE TROUGH IS CURRENTLY APPROACHING THE MISSISSIPPI RIVER...WHILE A STRONGER WAVE DIVES SOUTHWARD INTO MINNESOTA. FIRST WAVE WILL SPARK WIDELY SCATTERED SHOWERS/THUNDER ACROSS THE AREA THIS MORNING...WITH AREAL COVERAGE REMAINING RATHER LOW. AS ATMOSPHERE DESTABILIZES...GREATEST INSTABILITY WILL SET UP ACROSS THE OHIO RIVER VALLEY INTO EAST-CENTRAL ILLINOIS THIS AFTERNOON. MODIFIED NAM FORECAST SOUNDING FOR KLWV INDICATES CAPE VALUES OF AROUND 1500J/KG AFTER 18Z. IN ADDITION...AS MINNESOTA UPPER WAVE APPROACHES...0-6KM BULK SHEAR VALUES WILL INCREASE INTO THE 30 TO 40KT RANGE ACROSS THE AREA OF BEST INSTABILITY. THEREFORE THINK A NARROW WINDOW OF OPPORTUNITY EXISTS FOR SCATTERED STRONG TO SEVERE THUNDERSTORMS ALONG THE ADVANCING COLD FRONT DURING THE LATE AFTERNOON AND EARLY EVENING HOURS. WILL CARRY 40 POPS ACROSS MOST OF THE AREA...WITH SLIGHTLY HIGHER 50S ALONG/EAST OF I-57 WHERE INSTABILITY/SHEAR PARAMETERS BETTER COINCIDE WITH ONE ANOTHER THIS AFTERNOON/EVENING. AS WAVE DIGS SOUTHEASTWARD...AN UNSEASONABLY STRONG UPPER LOW WILL DEVELOP OVER THE SOUTHERN GREAT LAKES ON FRIDAY. GIVEN PROXIMITY OF DEEP LOW AND RESULTING CYCLONIC FLOW...THINK A FEW LIGHT SHOWERS WILL BE POSSIBLE ACROSS EAST-CENTRAL ILLINOIS THROUGHOUT THE DAY. WITH BRISK NORTHERLY WINDS OF 10 TO 15 MPH AND 850MB TEMPS DROPPING INTO THE 10 TO 12C RANGE...HIGH TEMPS WILL DROP BELOW NORMAL IN THE MIDDLE TO UPPER 70S. SKIES WILL CLEAR AND WINDS WILL DIMINISH FRIDAY NIGHT...SETTING UP THE COOLEST NIGHT OF THE FORECAST PERIOD. GOOD RADIATIONAL COOLING OF DRY AIRMASS WILL ALLOW LOWS TO DROP INTO THE MIDDLE TO UPPER 50S. MET GUIDANCE EVEN SUGGESTS SOME FAVORED LOCATIONS MAY DIP INTO THE UPPER 40S...BUT DUE TO CONTINUED LIGHT NORTHERLY WINDS...WILL NOT GO QUITE THAT LOW. ANOTHER PLEASANT DAY WILL BE IN STORE FOR SATURDAY...WITH SLOW MODIFICATION OF THE AIRMASS PUSHING HIGH TEMPS TO AROUND 80 DEGREES. LONG TERM...SUNDAY THROUGH WEDNESDAY GFS/ECMWF BOTH CONTINUE TO ADVERTISE A WEAK SHORT-WAVE TRACKING THROUGH THE MIDWEST SUNDAY INTO MONDAY...ALTHOUGH MINOR STRENGTH AND TIMING DIFFERENCES ARE STILL SHOWING UP FROM RUN-TO-RUN. GIVEN VERY DRY INITIAL AIRMASS...DO NOT THINK THIS FEATURE WILL PRODUCE MUCH PRECIP. EVEN STILL...WILL CARRY A SLIGHT CHANCE POP SUNDAY NIGHT AND MONDAY WHEN MODEL CONSENSUS BRINGS STRONGEST LIFT ACROSS THE AREA. AFTER THAT...UPPER RIDGE WILL BEGIN TO BUILD BACK EASTWARD AND TEMPS WILL ONCE AGAIN RISE INTO THE 90S BY TUESDAY AND WEDNESDAY. BARNES && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE LINCOLN IL 1137 AM CDT THU AUG 9 2012 ILZ027>031-036>038-040>043-047>053-101645- CASS-CHRISTIAN-DE WITT-FULTON-KNOX-LOGAN-MACON-MARSHALL-MASON- MCLEAN-MENARD-MORGAN-PEORIA-SANGAMON-SCHUYLER-SCOTT-STARK- TAZEWELL-WOODFORD- 1137 AM CDT THU AUG 9 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL ILLINOIS. .DAY ONE...THIS AFTERNOON AND TONIGHT SCATTERED THUNDERSTORMS WILL DEVELOP THIS AFTERNOON AHEAD OF A LOW PRESSURE SYSTEM. WHILE WIDESPREAD SEVERE WEATHER IS NOT ANTICIPATED...A FEW STORMS MAY PRODUCE STRONG WIND GUSTS AND LARGE HAIL. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON...PRIMARILY BETWEEN 2 PM AND 6 PM. ILZ044>046-054>057-061>063-066>068-071>073-101645- CHAMPAIGN-CLARK-CLAY-COLES-CRAWFORD-CUMBERLAND-DOUGLAS-EDGAR- EFFINGHAM-JASPER-LAWRENCE-MOULTRIE-PIATT-RICHLAND-SHELBY- VERMILION- 1137 AM CDT THU AUG 9 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL ILLINOIS...EAST CENTRAL ILLINOIS AND SOUTHEAST ILLINOIS. .DAY ONE...THIS AFTERNOON AND TONIGHT SCATTERED THUNDERSTORMS WILL DEVELOP THIS AFTERNOON AND EVENING AHEAD OF A LOW PRESSURE SYSTEM. SEVERE WEATHER WILL BE POSSIBLE...WITH THE MAIN THREATS BEING DAMAGING WIND GUSTS AND LARGE HAIL. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EVENING... MAINLY BETWEEN 4 PM AND 8 PM. 25
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LINCOLN IL
1058 AM CDT THU AUG 09 2012
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1200 AM HEAVY RAIN 4 SW NEWMAN 39.76N 88.04W
08/09/2012 M1.35 INCH DOUGLAS IL MESONET
24-HOUR PRECIPITATION TOTAL...FROM SWOP
0600 AM HEAVY RAIN SHELBYVILLE 39.41N 88.80W
08/09/2012 M1.50 INCH SHELBY IL CO-OP OBSERVER
24-HOUR PRECIPITATION TOTAL RECORDED AT THE SHELBYVILLE
DAM
0630 AM HEAVY RAIN WINDSOR 39.44N 88.60W
08/09/2012 M1.23 INCH SHELBY IL CO-OP OBSERVER
24-HOUR PRECIPITATION TOTAL
0700 AM HEAVY RAIN 4 NW WINDSOR 39.48N 88.65W
08/09/2012 M1.04 INCH SHELBY IL MESONET
24-HOUR PRECIPITATION...FROM SWOP
0700 AM HEAVY RAIN PARIS 39.62N 87.69W
08/09/2012 M1.30 INCH EDGAR IL CO-OP OBSERVER
24-HOUR PRECIPITATION TOTAL
0700 AM HEAVY RAIN NW PARIS 39.62N 87.69W
08/09/2012 M1.27 INCH EDGAR IL COCORAHS
24-HOUR PRECIPITATION TOTAL
0700 AM HEAVY RAIN 4 NNW PARIS 39.67N 87.72W
08/09/2012 M1.25 INCH EDGAR IL COCORAHS
24-HOUR PRECIPITATION TOTAL
0700 AM HEAVY RAIN SHELBYVILLE 39.41N 88.80W
08/09/2012 M1.73 INCH SHELBY IL COCORAHS
24-HOUR PRECIPITATION TOTAL
0800 AM HEAVY RAIN MATTOON 39.48N 88.37W
08/09/2012 M1.28 INCH COLES IL CO-OP OBSERVER
24-HOUR PRECIPITATION TOTAL
&&
LAUFENBERGThe Lincoln radar (KILX), 77 km away, was scanning. The volume nearest the first event began at 20:06 UTC.
13 thunderstorm wind, 7 hail. Local standard time, as filed.
A 12-inch diameter tree was blown down, bringing a power line down with it. A road was blocked by the tree.
Numerous trees and power lines were blown down in Toluca.
Numerous trees and tree branches were blown down in Danvers.
Downburst winds of 70 to 80 mph produced a wide swath of damage from Danvers southeastward into the southwest side of Bloomington. One of the hardest hit locations along this path was the Apollo Acres subdivision just north of Illinois Route 9, where 159 homes sustained damage. 139 of those homes had awnings or shingles damaged, while 19 suffered minor roof and window damage, and 1 home had one-third of its roof torn off. Total damage in Apollo Acres was around $1 million. Other significant damage occurred along the path of the storm, including numerous downed trees, trailers blown over, and several large metal buildings with doors blown in and roofs torn off. Total damage to 30 businesses along the path was estimated at around $2.5 million. One minor injury was reported, as a car was hit by a wind-blown trailer.
Hail damaged crops along a 1.5 mile-long/50 yards-wide swath just north of Heyworth.
Strong thunderstorm winds produced damage across a 2 square mile area on the west and southwest side of Champaign. Numerous tree branches and power lines were blown down, creating a power outage for several hours. The damage was bounded by Springfield Avenue on the north, Prospect Avenue on the east, Windsor Avenue on the south, and Duncan Road on the west.
Ten train cars were derailed by strong winds about 3 miles south of Sidney.
Numerous tree branches were blown down.
A few trees were topped and several power lines were blown down just south of Sidney. In addition, a corn field was flattened.
A tree branch was blown onto a vehicle on County Road 1100 North about 1.5 miles north of Sidney.
Several tree limbs were blown down.
Numerous trees and tree branches were blown down. Roof damage was reported to 29 structures. A garage was destroyed and several machine sheds were severely damaged or destroyed. In addition, a grain silo was damaged.
Three power poles were snapped and several tree branches were blown down.
Three large trees were blown down.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2012Every state in 2012This day in weather historyWarnings in Illinois, August 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: 399135, 399128, 399129, 399134, 399126, 399127, 399130, 399131, 399145, 399132, 399144, 399133, 399136, 399138, 399139, 399143, 399137, 399140, 399141, 399142.