A thunderstorm moved southeast across northeast Iowa then northwest Illinois during the evening of May 31st. This storm moved into LaSalle County then weakened.
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 LOT wrote it up.
A thunderstorm moved southeast across northeast Iowa then northwest Illinois during the evening of May 31st. This storm moved into LaSalle County then weakened.
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 Chicago, IL wrote its last area forecast discussion before the first event at May 31, 5:34 PM CST, 4 hours 27 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 634 PM CDT SAT MAY 31 2008 .DISCUSSION... 325 PM CDT MAIN FORECAST CONCERN TODAY IS POTENTIAL FOR ISOLATED SHOWERS/STORMS THIS EVENING AND SUNDAY ALONG WITH PERIODIC PRECIP CHANCES NEXT WEEK. THE COMBINATION OF SURFACE TEMPERATURES WARMING TO AROUND 80 AND FAIRLY COOL MID LEVELS ASSOCIATED WITH DEPARTING MID LEVEL TROUGH ACROSS THE GREAT LAKES REGION HAS LED TO SOME WEAK TO MODERATE INSTABILITY...ESPECIALLY FROM WEST CENTRAL ILLINOIS INTO WEST CENTRAL MINNESOTA WHERE LOW LEVELS ARE A BIT WARMER. VISIBLE SATELLITE IMAGERY IS NOW INDICATING THUNDERSTORMS DEVELOPING ACROSS EASTERN SOUTH DAKOTA INTO SOUTH CENTRAL MINNESOTA. MODIFYING MORNING RAOBS FOR CURRENT TEMPS/TD GENERALLY YIELD BETWEEN 800-1000 J/KG OF SB BASED INSTABILITY ACROSS MUCH OF NORTHERN ILLINOIS THIS AFTERNOON. WATER VAPOR IMAGERY ALSO SUGGESTS A SHORT WAVE DROPPING SOUTHEASTWARD ACROSS NORTH CENTRAL MINNESOTA AND ANOTHER MORE SHEARED OUT UPPER LEVEL VORT MAX FROM EASTERN NEBRASKA THROUGH SOUTHEAST IOWA. GIVEN WEAK UPPER FORCING AND DIURNAL INSTABILITY WILL MAINTAIN LOW CHANCE POPS ACROSS FAR NORTHWEST ILLINOIS FOR THE EVENING AND SLIGHT CHANCE POPS ACROSS MOST OF THE REMAINDER OF THE NORTHERN ILLINOIS PORTION OF THE FORECAST AREA. FAR NORTHWEST PORTIONS OF THE FORECAST AREA REMAIN IN A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR LATE THIS AFTERNOON/EARLY EVENING ALTHOUGH AT THIS TIME EXPECTING GREATER SEVERE POTENTIAL TO REMAIN OFF TO THE NORTH AND NORTHWEST. WITH THE LOSS OF DIURNAL INSTABILITY LATER THIS EVENING...SKIES SHOULD BECOME MOSTLY CLEAR BY LATE EVENING. A RATHER SIMILAR DAY IS EXPECTED FOR SUNDAY WITH THERMODYNAMIC PROFILES EXPECTED TO BE MUCH THE SAME AS DAY. ONLY DIFFERENCE TOMORROW WILL BE FOR EVEN WEAKER SYNOPTIC SCALE FORCING AS THE GREAT LAKES MID LEVEL TROUGH CONTINUES TO TRACK OFF TO THE EAST. LOW LEVEL HEIGHT GRADIENT SHOULD BE WEAKER TOMORROW HOWEVER SO EXPECTING A LAKE BREEZE TO DEVELOP DURING THE AFTERNOON WITH TEMPERATURES COOLING BACK INTO THE LOWER 70S LAKESHORE AREAS DURING THE AFTERNOON. ANY SHOWER COVERAGE TOMORROW AFTERNOON SHOULD BE VERY LIMITED GIVEN EXPECTED WEAKER FORCING...SO WILL ONLY MENTION SLIGHT CHANCE POPS AT THIS TIME. PERHAPS BEST PROSPECTS FOR ANY ISOLATED SHOWERS WILL BE ALONG AFTERNOON LAKE BREEZE. A WEAK SHORT WAVE RIDGE WILL BUILD INTO THE WESTERN GREAT LAKES EARLY MONDAY WITH THE NEXT FAST MOVING PACIFIC SHORT WAVE EXPECTED TO APPROACH THE CENTRAL PLAINS ON MONDAY. GFS/NAM HAVE BEEN CONSISTENT IN DEVELOPING STRONG LOW LEVEL JET MONDAY NIGHT ACROSS MID MS RIVER VALLEY IN ADVANCE OF THIS SHORT WAVE. SETUP SEEMS FAVORABLE FOR NOCTURNAL MCS MONDAY NIGHT WITH A POTENTIAL OF MORE HEAVY RAINFALL AS 850 HPA DEW POINTS OF +13 TO +15 DEG C ARE ADVECTED BACK NORTHWARD ALONG WITH PWATS EXCEEDING 1.5 INCHES. MORE THUNDERSTORMS ARE EXPECTED TUESDAY AS MAIN MID/UPPER LEVEL FORCING APPROACHES THE WESTERN GREAT LAKES. AGAIN JUST MAINTAINED CHANCE POPS ON TUESDAY WITH STILL SOME QUESTIONS REGARDING HOW OVERNIGHT OUTFLOWS FROM POSSIBLE MONDAY NIGHT MCS WILL INFLUENCE PRECIP COVERAGE/TIMING/LOCATION ON TUESDAY. A LULL IN PRECIP CHANCES EXPECTED FOR MOST OF WEDNESDAY AS A SURFACE HIGH BUILDS INTO THE AREA...BUT A MORE AMPLIFIED UPPER TROUGH IS EXPECTED TO DIG INTO THE WESTERN CONUS ON WEDNESDAY WITH SHARPENING WARM FRONTAL BOUNDARY DEVELOPING ACROSS THE CENTRAL PLAINS. AS THIS TROUGH TRACKS EAST...THE WARM FRONT IS EXPECTED TO LIFT THROUGH WESTERN GREAT LAKES ON THURSDAY WITH CONTINUED CHANCE OF THUNDER...WITH PRECIP CHANCE CONTINUING INTO FRIDAY AS UPPER TROUGH MOVES INTO THE PLAINS. TEMPERATURES THROUGH THE PERIOD SHOULD REMAIN AT OR ABOVE NORMAL...ALTHOUGH COOLER LAKE TEMPS ARE EXPECTED AGAIN ON WEDNESDAY NORTH OF THE WARM FRONT WITH EASTERLY FLOW EXPECTED. MARSILI && .AVIATION... 633 PM CDT RE 00Z TAFORS...WATER VAPOR SATELLITE LOOP SHOWS MULTIPLE SMALL DISTURBANCES DROPPING SOUTHEAST OUT OF SOUTH CENTRAL CANADA ACROSS ND AND MN TOWARDS WI. THESE IMPULSES KICKING OFF TSRA WITH HEAT OF THE DAY. SMALL STRONG CLUSTER IN FAR NORTHEAST IA ON SURFACE TROUGH THAT EXTENDS SE OUT OF WI WHICH IS PRECEDED BY DEW POINTS OF MID 50S TO LOWER 60S. WHILE THESE ARE EXPECTED TO PERSIST THROUGH SUNDOWN AS HAVE SOME LOW LEVEL FORCING AND MID LEVEL SUPPORT...FEEL THAT WILL BE DYING OUT AS THE MOVE INTO NORTHERN IL WITH WEAK FORCING /SFC WINDS ALREADY WNW AHEAD OF TROUGH/ AND BEGINNING OF COOLING OF BL. EXTRAPOLATION BRINGS REMNANTS INTO KRFD VC BY 02Z. FURTHER SE...A FEW CELLS HAVE TRIED TO GET GOING OVER THE LOWER IL RIVER VALLEY. NOT VERY IMPRESSIVE AND IF THEY HOLD ON TIL SUNSET WILL BE PASSING TO THE SW AND S OF THE TERMINALS. WNW WINDS GUSTING INTO UP TO MID 20KTS WILL BE DROPPING OF DIURNALLY AND EXPECTED TO BECOME LIGHT VARIABLE/NIL OVERNIGHT WITH WEAK HI CURRENTLY OVER NORTHERN WI TO SETTLE OVER THE TERMINALS OVERNIGHT. TRS && .MARINE... 115 PM CDT A BROAD AREA OF LOW PRESSURE OVER EASTERN ONTARIO/WESTERN QUEBEC WILL CONTINUE TO MOVE EASTWARD ACROSS THE LOWER ST. LAWRENCE VALLEY TONIGHT. BEHIND IT...WEAK RIDGE OF HIGH PRESSURE FROM THE NORTHERN PLAINS...SOUTHEASTWARD TO THE GULF STATES WILL DRIFT SLOWLY EASTWARD THROUGH SUNDAY...EVENTUALLY SETTLING OVER THE OHIO VALLEY BY MONDAY. ANOTHER DIFFUSE AREA OF LOW PRESSURE WILL DEVELOP OVER THE CENTRAL PLAINS MONDAY... AND EVENTUALLY CONSOLIDATE INTO A LOW CENTER OVER THE MISSOURI VALLEY MONDAY NIGHT. THIS LOW IS THEN FORECAST TO MOVE ACROSS THE WESTERN GREAT LAKES TUESDAY AND TUESDAY NIGHT. DUE TO THE GENERALLY WEAK PRESSURE PATTERN ACROSS THE GREAT LAKES OVER THE NEXT SEVERAL DAYS...WINDS AND WAVES ARE EXPECTED TO REMAIN ON THE LIGHT SIDE...FOR THE MOST PART...INTO MIDWEEK. MERZLOCK && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 356 PM CDT SAT MAY 31 2008 ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019- 012100- WINNEBAGO-BOONE-MCHENRY-LAKE ILLINOIS-OGLE-LEE-DE KALB-KANE- DUPAGE-COOK-LA SALLE-KENDALL-GRUNDY-WILL-KANKAKEE-LIVINGSTON- IROQUOIS-FORD-LAKE INDIANA-PORTER-NEWTON-JASPER-BENTON- 356 PM CDT SAT MAY 31 2008 /456 PM EDT SAT MAY 31 2008/ THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL ILLINOIS...NORTHEAST ILLINOIS AND NORTHWEST INDIANA. .DAY ONE...TONIGHT. WEATHER HAZARDS EXPECTED: SMALL HAIL. LIGHTNING. AREAS AFFECTED AND TIMING: ISOLATED THUNDERSTORMS ARE POSSIBLE EARLY THIS EVENING. A FEW STORMS EARLY THIS EVENING MAY PRODUCE SOME SMALL HAIL ACROSS NORTHWEST ILLINOIS MAINLY WEST OF A SOUTH BELOIT TO DIXON LINE. DISCUSSION: A WEAK UPPER LEVEL DISTURBANCE APPROACHING FROM THE NORTHERN PLAINS HAS RESULTED IN SCATTERED THUNDERSTORMS ACROSS SOUTHERN MINNESOTA. A FEW OF THESE STORMS MAY MOVE INTO NORTHWEST ILLINOIS THIS EVENING WITH A POTENTIAL FOR SOME SMALL HAIL. THE THREAT OF ISOLATED THUNDERSTORMS WILL END TOWARD MIDNIGHT. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY. THERE WILL BE PERIODIC CHANCES OF SHOWERS AND THUNDERSTORMS MONDAY NIGHT AND TUESDAY...AND THEN AGAIN LATE WEDNESDAY INTO FRIDAY. THERE IS A RISK OF HEAVY RAINFALL MONDAY NIGHT...AND A POTENTIAL FOR SEVERE WEATHER AGAIN ON TUESDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED TONIGHT. && COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO WEBPAGE: WEATHER.GOV/CHICAGO LMZ740>745-012100- WINTHROP HARBOR TO WILMETTE HARBOR- WILMETTE HARBOR TO NORTHERLY ISLAND- NORTHERLY ISLAND TO CALUMET HARBOR-CALUMET HARBOR TO GARY- GARY TO BURNS HARBOR-BURNS HARBOR TO MICHIGAN CITY- 356 PM CDT SAT MAY 31 2008 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF THE ILLINOIS NEARSHORE WATERS OF LAKE MICHIGAN AND THE INDIANA NEARSHORE WATERS OF LAKE MICHIGAN. .DAY ONE...TONIGHT. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY. THERE WILL BE PERIODIC CHANCES OF SHOWERS AND THUNDERSTORMS MONDAY NIGHT AND TUESDAY...AND THEN AGAIN LATE WEDNESDAY INTO FRIDAY. && COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO WEBPAGE: WEATHER.GOV/CHICAGO LMZ080-261-362-364-366-563-565-567-669-671-673-675-777-779-868- 870-872-874-876-878-012100- LAKE MICHIGAN FROM MICHIGAN CITY IN TO ST. JOSEPH MI 5 NM OFFSHORE TO MID LAKE- LAKE MICHIGAN FROM SEUL CHOIX POINT TO ROCK ISLAND PASSAGE 5 NM OFFSHORE TO MID LAKE- LAKE MICHIGAN SOUTH OF A LINE FROM SEUL CHOIX POINT TO THE MACKINAC BRIDGE AND NORTH OF A LINE FROM CHARLEVOIX MI TO SOUTH FOX ISLAND 5 NM OFFSHORE- LAKE MICHIGAN FROM CHARLEVOIX TO POINT BETSIE MI 5 NM OFFSHORE TO MID LAKE- LAKE MICHIGAN FROM POINT BETSIE TO MANISTEE MI 5 NM OFFSHORE TO MID LAKE- LAKE MICHIGAN FROM ROCK ISLAND PASSAGE TO STURGEON BAY WI- LAKE MICHIGAN FROM STURGEON BAY TO TWO RIVERS WI 5 NM OFFSHORE TO MID LAKE- LAKE MICHIGAN FROM TOW RIVERS TO SHEBOYGAN WI 5 NM OFFSHORE TO MID LAKE- LAKE MICHIGAN FROM SHEBOYGAN TO PORT WASHINGTON WI 5 NM OFFSHORE TO MID LAKE- LAKE MICHIGAN FROM PORT WASHINGTON TO NORTH POINT LIGHT WI 5 NM OFFSHORE TO MID LAKE- LAKE MICHIGAN FROM NORTH POINT LIGHT TO WIND POINT WI 5 NM OFFSHORE TO MID LAKE- LAKE MICHIGAN FROM WIND POINT WI TO WINTHROP HARBOR IL 5 NM OFFSHORE TO MID LAKE- LAKE MICHIGAN FROM WINTHROP HARBOR TO WILMETTE HARBOR IL 5 NM OFFSHORE TO MID LAKE- LAKE MICHIGAN FROM WILMETTE HARBOR IL TO MICHIGAN CITY IN 5 NM OFFSHORE TO MID LAKE- LAKE MICHIGAN FROM PENTWATER TO MANISTEE MI 5 NM OFFSHORE TO MID LAKE- LAKE MICHIGAN FROM WHITEHALL TO PENTWATER MI 5 NM OFFSHORE TO MID LAKE- LAKE MICHIGAN FROM GRAND HAVEN TO WHITEHALL MI 5 NM OFFSHORE TO MID LAKE- LAKE MICHIGAN FROM HOLLAND TO GRAND HAVEN MI 5 NM OFFSHORE TO MID LAKE- LAKE MICHIGAN FROM SOUTH HAVEN TO HOLLAND MI 5 NM OFFSHORE TO MID LAKE- LAKE MICHIGAN FROM ST. JOSEPH TO SOUTH HAVEN MI 5 NM OFFSHORE TO MID LAKE- 356 PM CDT SAT MAY 31 2008 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF THE OPEN WATERS OF LAKE MICHIGAN. .DAY ONE...TONIGHT. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY. THERE WILL BE PERIODIC CHANCES OF SHOWERS AND THUNDERSTORMS MONDAY NIGHT AND TUESDAY...AND THEN AGAIN LATE WEDNESDAY INTO FRIDAY. && COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO WEBPAGE: WEATHER.GOV/CHICAGO MARSILI
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
552 PM CDT SAT MAY 31 2008
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0415 PM FLOOD FOWLER 40.62N 87.32W
05/31/2008 BENTON IN LAW ENFORCEMENT
2 ROADS IN FOWLWER CLOSED. ALSO ONE ROAD CLOSED IN GILBOA
TOWNSHIP AND ONE IN PINE TOWNSHIP.
&&
RODRIGUEZPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
557 PM CDT SAT MAY 31 2008
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0415 PM FLOOD MILFORD 40.63N 87.70W
05/31/2008 IROQUOIS IL LAW ENFORCEMENT
VIADUCT IS COMPLETELY FULL MAKING RT.1 IMPASSIBLE.
&&
RODRIGUEZPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
604 PM CDT SAT MAY 31 2008
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0415 PM FLOOD 2 SW ONARGA 40.69N 88.04W
05/31/2008 IROQUOIS IL LAW ENFORCEMENT
RT. 45 AT ROAD 1200N CLOSED.
&&
RODRIGUEZPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
609 PM CDT SAT MAY 31 2008
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0415 PM FLOOD 2 SE SHELDON 40.75N 87.54W
05/31/2008 IROQUOIS IL LAW ENFORCEMENT
ROAD 3100E BETWEEN 1300N AND 1200N CLOSED. ROAD 3200E
BETWEEN 1500N AND 1400N ALSO CLOSED.
&&
RODRIGUEZThe Chicago radar (KLOT), 94 km away, was scanning. The volume nearest the first event began at 04:02 UTC.
1 thunderstorm wind. Local standard time, as filed.
Large construction message boards were blown over on Interstate 80, near the LaSalle County line.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Illinois in 2008Every state in 2008This day in weather historyWarnings in Illinois, May 2008
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: 94983.