A convective thunderstorm complex originated in southern Minnesota, and moved southeast to the Chicago area. Powerful downburst winds were generated.
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 MKX wrote it up.
A convective thunderstorm complex originated in southern Minnesota, and moved southeast to the Chicago area. Powerful downburst winds were generated. The complex was associated with a short-wave trough aloft, and good warm-air advection at 850 mb. Air temperatures were in the lower to mid 80s and surface dewpoints were in the upper 60s to lower 70s.
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 Milwaukee, WI wrote its last area forecast discussion before the first event at Jul 31, 3:48 AM CST, 6 hours 57 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 448 AM CDT THU JUL 31 2008 .SHORT TERM...EXPECT MCS OVER THE ERN DAKOTAS TO DIVE SEWD ALONG THE INSTABILITY GRADIENT OVER SRN MN AND EVENTUALLY INTO IA. BELIEVE MODEL QPF MAY BE DISPLACED TOO FAR NORTH AND EAST LATER TODAY AND TNT BASED ON EXPECTED LOCATION OF CAPE GRADIENT NEAR THE MS RIVER. THE NOSE OF A WEAK LLJ AND 850 MB THERMAL RIDGE FOR LATER TODAY AND TNT ALSO STAYS FARTHER WEST AS IT VEERS FROM THE CURRENT LOCATION IN THE DAKOTAS TO IA AND EVENTUALLY IL. THE 925-850 MB Q-VECTOR CONVERGENCE IS MAXIMIZED OVER SRN MN INTO NW IL AS WELL. TRENDED POPS FROM NO PCPN IN THE NE CWA TO 40S POPS IN THE SW CWA FOR TNT. THE WEAK LOW PRESSURE AREA OVER SD THAT IS ASSOCIATED WITH THE LIFT AND PCPN WILL SHIFT SEWD FROM IA AND NRN IL FRI AM TOWARD THE OHIO RIVER DURING THE DAY ON FRI. SOME ISOLD TO SCT PCPN MAY BE ONGOING MAINLY FRI AM OVER SRN WI SO SMALL POPS CONTINUE. HIGH PRESSURE TO BUILD INTO WI FOR FRI NT AND SAT WHILE AN UPPER RIDGE AXIS SHIFTS EWD ACROSS THE PLAINS. HIGH TEMPS TO REMAIN MAINLY IN THE MID 80S THROUGH THE WEEKEND WITH LAKE MICHIGAN LAKE BREEZES EACH DAY IN THE EAST. .LONG TERM... WARM ADVECTION RETURNS SUNDAY INTO EARLY NEXT WEEK AS A WARM FRONT EXTENDS EWD FROM LOW PRESSURE OVER THE PLAINS. THIS PATTERN WILL HOLD POSSIBLY INTO MID WEEK AS REGION REMAINS ON SRN PERIPHERY OF THE STRONGER WESTERLIES AND FRONT REMAINS NEARLY STATIONARY. PCPN CHANCES WILL CONTINUE DUE TO PROXIMITY OF FRONT TO SRN WI. MONDAY HAS THE BEST POTENTIAL TO BE A HOT DAY. && .AVIATION...FR CONDITIONS THROUGH PERIOD. CHC FOR THUNDERSTORMS INCREASES SLIGHTLY TONIGHT...MAINLY FOR KMSN...ASSOC WITH WEAK LOW PRES APPROCHING FROM CNTRL PLAINS. FLOW REMAINS VERY WEAK AND IS PROBLEMATIC WITH RESPECT TO PINPOINTING STORM DEVELPMENT AND MOVEMENT. STORM COMPLEX OVER SCNTRL NDKTA THIS MORNING SHOULD STAY MAINLY TO OUR WEST. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && SHORT/LONG TERM...20 AVIATION/MARINE...05
HAZARDOUS WEATHER OUTLOOK...UPDATED NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 930 AM CDT THU JUL 31 2008 WIZ046-047-051-052-056>060-062>072-010930- MARQUETTE-GREEN LAKE-FOND DU LAC-SHEBOYGAN-SAUK-COLUMBIA-DODGE- WASHINGTON-OZAUKEE-IOWA-DANE-JEFFERSON-WAUKESHA-MILWAUKEE- LAFAYETTE-GREEN-ROCK-WALWORTH-RACINE-KENOSHA- 930 AM CDT THU JUL 31 2008 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST CENTRAL WISCONSIN...SOUTH CENTRAL WISCONSIN AND SOUTHEAST WISCONSIN. .DAY ONE...TODAY AND TONIGHT A CLUSTER OF THUNDERSTORMS WILL MOVE INTO PORTIONS OF SOUTH CENTRAL WISCONSIN THIS MORNING. THE GREATEST THREAT AREA APPEARS TO BE AREAS ALONG AND SOUTHWEST OF A LINE FROM THE DELLS TO JANESVILLE. SOME OF THE STORMS MAY BE SEVERE WITH DAMAGING WINDS. THERE IS A CHANCE OF THUNDERSTORMS TONIGHT MAINLY WEST OF A LINE STRETCHING FROM BURLINGTON TO MONTELLO. THERE IS ALSO A SLIGHT RISK OF SEVERE THUNDERSTORMS WITH LARGE HAIL AND STRONG WINDS THE MAIN THREAT. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY HEAT INDEX VALUES MAY REACH INTO THE MID 90S SUNDAY THROUGH TUESDAY...AWAY FROM LAKE MICHIGAN. THERE IS A CHANCE OF THUNDERSTORMS ON FRIDAY...MAINLY IN THE MORNING. THERE IS A CHANCE OF THUNDERSTORMS AGAIN SUNDAY THROUGH WEDNESDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED THIS MORNING. LMZ643>646-010930- SHEBOYGAN TO PORT WASHINGTON WI- PORT WASHINGTON TO NORTH POINT LIGHT WI- NORTH POINT LIGHT TO WIND POINT WI- WIND POINT WI TO WINTHROP HARBOR IL- 930 AM CDT THU JUL 31 2008 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF LAKE MICHIGAN. .DAY ONE...TODAY AND TONIGHT THERE IS A SLIGHT CHANCE OF THUNDERSTORMS TONIGHT...MAINLY SOUTH OF PORT WASHINGTON. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY THERE IS A CHANCE OF THUNDERSTORMS ON FRIDAY...MAINLY IN THE MORNING. THERE IS A CHANCE OF THUNDERSTORMS AGAIN SUNDAY THROUGH WEDNESDAY. COLLAR WWW.WEATHER.GOV/MKX
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 1056 AM CDT THU JUL 31 2008 WIZ056-062-063-067>069-311730- SAUK-IOWA-DANE-LAFAYETTE-GREEN-ROCK- INCLUDING THE CITIES OF...BARABOO...DODGEVILLE...MADISON... DARLINGTON...MONROE...JANESVILLE...BELOIT 1056 AM CDT THU JUL 31 2008 ...STRONG THUNDERSTORMS APPROACHING SOUTHWEST WISCONSIN... AT 1055 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A BROKEN LINE OF STRONG THUNDERSTORMS ALONG A LINE FROM VIROQUA...TO GAYS MILLS...TO JUST NORTHEAST OF WATERLOO IOWA...MOVING SOUTHEAST AROUND 50 MPH. THE LINE HAS EXHIBITED A WEAKENING TREND OVER THE PAST COUPLE HOURS...HOWEVER AS THE LINE TRACKS ACROSS PORTIONS OF SOUTH CENTRAL WISCONSIN IT WILL STILL BE CAPABLE OF PRODUCING SMALL HAIL...GUSTY WINDS TO 50 MPH...HEAVY RAIN...AND FREQUENT LIGHTNING. IF IT HOLDS TOGETHER...THE LINE WILL AFFECT AREAS SOUTHWEST OF A LINE FROM LONE ROCK TO BRODHEAD BY EARLY AFTERNOON. THUNDERSTORMS SHOULD APPROACH ARENA...MINERAL POINT...AND DARLINGTON AROUND 1145 AM...AND MADISON AND MONROE AROUND 1215 PM. THE REMAINDER OF SOUTH CENTRAL WISCONSIN MAY HAVE A PERIOD OF LIGHT TO MODERATE RAIN THROUGH EARLY AFTERNOON...HOWEVER THE RAIN SHIELD IS SHRINKING ACCORDING TO RECENT RADAR TRENDS. IF YOU HAVE OUTDOOR PLANS TODAY...BE PREPARED TO SEEK INDOOR SHELTER IF THUNDERSTORMS APPROACH YOUR LOCATION. BORGHOFF
The La Crosse radar (KARX), 128 km away, was scanning. The volume nearest the first event began at 16:45 UTC.
4 thunderstorm wind. Local standard time, as filed.
Powerful thunderstorm winds toppled large trees, and knocked down large tree branches that brought down some power-lines.
Powerful thunderstorm winds toppled large trees.
Powerful thunderstorm winds toppled large trees, and knocked down tree branches that brought down power-lines.
Powerful thunderstorm winds toppled large trees, and knocked down tree branches that brought down power-lines.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wisconsin in 2008Every state in 2008This day in weather historyWarnings in Wisconsin, July 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: 120326, 120327, 120330, 120334.