The month ended with several lines of strong and severe thunderstorms crossing Southeast Wisconsin during the late evening hours of July 30th into the early morning hours of July 31st. 50 inch in diameter and damaging wind gusts up to 65 mph affected Fond Du Lac County with the first line, with a second line hitting locations along and south of the Interstate 94 corridor from Dane County east to…
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.
The month ended with several lines of strong and severe thunderstorms crossing Southeast Wisconsin during the late evening hours of July 30th into the early morning hours of July 31st. Hail up to 1.50 inch in diameter and damaging wind gusts up to 65 mph affected Fond Du Lac County with the first line, with a second line hitting locations along and south of the Interstate 94 corridor from Dane County east to Lake Michigan. WE Energies reported 15,000 customers were without power.
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 30, 2:32 PM CST, 7 hours 8 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 332 PM CDT MON JUL 30 2012 .SHORT TERM... TONIGHT AND TOMORROW...FORECAST CONFIDENCE...MEDIUM TO HIGH. SPC HAS HIGHLIGHTED MUCH OF WISCONSIN WITH A SLIGHT RISK OF SEVERE WX NEAR COLD FRONT MOVING THROUGH THIS EVENING. THIS IS CERTAINLY JUSTIFIED BY EFFECTIVE BULK SHEAR VALUES HOVERING AROUND 30 KT AND MUCAPE OF 1500-2000 J/KG. MID-LEVEL WAA LARGELY CAPPING CONVECTION THIS AFTERNOON SHOULD BREAK JUST AHEAD OF THE FRONT. BEST UPPER LEVEL FORCING WILL BE AHEAD OF THE ACCOMPANYING SHORTWAVE WHICH WILL MAINLY AFFECT NRN WISCONSIN AND LOWER MICHIGAN. LOBE OF VORTICITY AT BASE OF TROUGH DOES PUSH ACROSS OUR AREA LATE TONIGHT...BUT THE FRONT SHOULD HAVE MOVED THROUGH BY THEN SO THE WAVE WON/T CONTRIBUTE TO SEVERE POTENTIAL FOR US. EXPECTING RAPID CLEARING BEHIND THE FRONT. GETTING SMALL TEMP/DEWPOINT SPREADS WITH LIGHT WINDS IN OUR NORTHWEST HALF SO WILL MENTION PATCHY FOG. TUESDAY NIGHT THROUGH WEDNESDAY...FORECAST CONFIDENCE MEDIUM TO HIGH. NORTHWEST FLOW WILL CONTINUE IN THE UPPER GREAT LAKES REGION THROUGH NEXT WEEKEND...WITH THE UPPER JET PARKED RIGHT OVER MN AND SOUTHERN WI AREA. A WEAK SHORTWAVE WILL ROLL ACROSS CENTRAL WI WED AFTERNOON...BUT SHOULD ONLY BRING A FEW MORE CLOUDS...SINCE IT WILL BE TOO DRY WITH SURFACE HIGH PRESSURE OVERHEAD. WITH RETURN FLOW AROUND THE HIGH...SOUTHWEST WINDS WILL USHER WARMER AIR BACK INTO SOUTH CENTRAL WI. ECMWF 925MB TEMPS RISE BACK TO 27C ONCE AGAIN...WITH THE NAM PUSHING 30C. THEREFORE...MAX TEMPS EXPECTED IN LOWER 90S ONCE AGAIN INLAND...WITH UPPER 80S NEAR THE SHORELINE. WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...FORECAST CONFIDENCE LOW. A SURFACE AND 925MB FRONTAL BOUNDARY WILL SAG SOUTHWARD ACROSS WI WED NIGHT AND STALL ACROSS SOUTHERN WI THU AND THU NIGHT. THE ECMWF STALLS THE 925MB AND 850MB BAROCLINIC ZONES FURTHER NORTH THAN THE NAM AND GFS...AND THEREFORE HAS THE PRECIP CHANCES FURTHER NORTH. GENERALLY SMALL CHANCES FOR THUNDERSTORMS WILL EXIST THROUGH THIS PERIOD AS A WEAK SHORTWAVE OR TWO PASSES BY WITH THE BAROCLINIC ZONE IN THE VICINITY OF SOUTHERN WI. NOT CERTAIN WHEN THE BEST CHANCE FOR THUNDERSTORMS WILL BE...BUT PROBABLY NOT A DROUGHT-BUSTING PRECIP EVENT. HIGHS WILL CONTINUE TO BE IN THE LOWER 90S WITH 925MB TEMPS REMAINING FAIRLY CONSTANT AROUND 27C. .LONG TERM... FRIDAY...FORECAST CONFIDENCE MEDIUM. A STRONG UPPER LOW WILL TRACK ACROSS THE US/CANADIAN BORDER OVER THE WEEKEND AND THE UPPER TROUGH WILL DROP DOWN ACROSS WI...ALONG WITH SURFACE LOW PRESSURE AND A TRAILING COLD FRONT. THIS UPPER LOW IS LOOKING FAIRLY STRONG...AND WILL BE COUPLED WITH THE RIGHT ENTRANCE REGION OF THE UPPER JET OVER SOUTHERN WI FOR A PERIOD OF TIME. BRIEF PERIOD OF ZONAL FLOW AHEAD OF THIS STRONG UPPER LOW WILL ALLOW A SHORTWAVE TO APPROACH SOUTHERN WI FROM THE WEST OR SOUTHWEST FRI EVENING. ENHANCED WARM AIR ADVECTION WITH THE VORT MAX AHEAD OF A DEVELOPING SURFACE LOW WILL HELP TO POSSIBLY INCREASE CLOUDS AND MAYBE TRIGGER SOME THUNDERSTORMS WEST OF THE FORECAST AREA. THE 12Z ECMWF CAME IN WITH A SLIGHTLY FASTER SOLUTION THAN PREVIOUS RUNS AND THE GFS. FOR NOW...DRY FORECAST FOR FRI. IF CONVECTION AND CLOUDS HOLD OFF...THE ECMWF HAS 24C TO 25C TEMPS SUPPORTING HIGHS IN THE UPPER 80S...SO INCREASED THE TEMPS FROM THE PREVIOUS FORECAST. FRIDAY NIGHT THROUGH SATURDAY NIGHT...FORECAST CONFIDENCE MEDIUM. THE MAIN UPPER LOW AND ASSOCIATED SURFACE LOW WILL ROLL ACROSS NORTHERN MN AND NORTHERN WI AND LAKE SUPERIOR SATURDAY TO SATURDAY NIGHT. WARM TEMPS COULD SNEAK IN AHEAD OF THE COLD FRONT ON SATURDAY AND LEAD TO YET ANOTHER DAY IN THE LOWER 90S. THUNDERSTORMS WILL BE POSSIBLE WITH THE WARM AIR ADVECTION FRIDAY NIGHT AND SATURDAY MORNING...BUT THE MAIN PRECIP EVENT NOW LOOKS TO BE ALONG AND JUST BEHIND THE SURFACE COLD FRONT. THE TIMING OF THIS FRONT SEEMS TO BE SLOWING DOWN WITH THE LATEST MODEL RUNS...SO BEST CHANCE FOR THUNDERSTORMS IN SOUTHERN WI SHOULD NOW BE SAT EVENING. SUNDAY THROUGH MONDAY...FORECAST CONFIDENCE MEDIUM. THE COLD FRONT AND UPPER TROUGH WILL BE THROUGH BY SUNDAY MORNING AND BRING A COOLER DAY WITH HIGHS AROUND 80. THE 12Z ECMWF NOW LINGERS PRECIP BEHIND THE FRONT THROUGH SUN MORNING. KEPT SUN DRY FOR NOW. MONDAY LOOKS DRY WITH HIGH PRESSURE IN PLACE. ECMWF SHOWS A WARMING TREND ONCE AGAIN FOR EARLY NEXT WEEK. WE JUST CANNOT GET RID OF THESE 90S. && .AVIATION/12Z TAFS/... VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE DAY TUESDAY. ONLY EXCEPTION WOULD BE THIS EVENING WITH A CHANCE OF THUNDERSTORMS. CERTAINLY A POSSIBILITY OF IFR TO MVFR VSBYS WITHIN HEAVIER RAINFALL. MONITORING THE POTENTIAL FOR SEVERE STORMS AS WELL...WITH LARGE HAIL AND DAMAGING WINDS THE PRIMARY THREATS. WILL PROBABLY LEAVE VCTS IN TAFS FOR NOW UNTIL CONFIDENCE IN AREAL COVERAGE OF STORMS INCREASES. BEST CHANCE FOR STORMS STILL SEEMS TO BE IN THE 22Z-03Z RANGE ACROSS SOUTHERN WISCONSIN. QUIET WEATHER THEN EXPECTED THROUGH TUESDAY AFTER SHOWERS AND STORMS WIND DOWN LATE THIS EVENING. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && TODAY/TONIGHT AND AVIATION/MARINE...WIMBERLEY/DDV TUESDAY THROUGH SUNDAY...MRC
HAZARDOUS WEATHER OUTLOOK...UPDATED NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 809 PM CDT MON JUL 30 2012 WIZ046-047-051-052-056>060-062>072-010115- MARQUETTE-GREEN LAKE-FOND DU LAC-SHEBOYGAN-SAUK-COLUMBIA-DODGE- WASHINGTON-OZAUKEE-IOWA-DANE-JEFFERSON-WAUKESHA-MILWAUKEE- LAFAYETTE-GREEN-ROCK-WALWORTH-RACINE-KENOSHA- 809 PM CDT MON JUL 30 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST CENTRAL WISCONSIN...SOUTH CENTRAL WISCONSIN AND SOUTHEAST WISCONSIN. .DAY ONE...TONIGHT THERE IS A CHANCE FOR THUNDERSTORMS LATE THIS EVENING. THERE IS A SLIGHT RISK THAT SOME OF THE STORMS MAY BECOME SEVERE WITH DAMAGING WINDS AND LARGE HAIL...ESPECIALLY EAST OF AN OXFORD...MADISON TO JANESVILLE LINE. THE WISCONSIN DNR HAS ISSUED AN AIR QUALITY ADVISORY FOR SHEBOYGAN...OZAUKEE...MILWAUKEE...RACINE AND KENOSHA COUNTIES UNTIL 11 PM CDT. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH MONDAY THERE WILL BE SMALL CHANCES OF THUNDERSTORMS WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. BETTER CHANCES FOR THUNDERSTORMS WILL BE EARLY IN THE WEEKEND...MAINLY ON SATURDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED LATE THIS EVENING. LMZ643>646-010115- 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- 809 PM CDT MON JUL 30 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF LAKE MICHIGAN. .DAY ONE...TONIGHT THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE EVENING AS A COLD FRONT MOVES THROUGH THE AREA. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH MONDAY THERE WILL BE SMALL CHANCES OF THUNDERSTORMS WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. BETTER CHANCES FOR THUNDERSTORMS WILL BE EARLY IN THE WEEKEND...MAINLY ON SATURDAY. REM WWW.WEATHER.GOV/MKX
The Green Bay radar (KGRB), 86 km away, was scanning. The volume nearest the first event began at 03:38 UTC.
6 hail, 4 thunderstorm wind. Local standard time, as filed.
The Fond Du Lac Emergency Manager reported large hail, estimated to be 1.50 inches in diameter, fell 2 miles southeast of the city of Fond Du Lac.
Law enforcement officers reported large hail, estimated to be 1 inch in diameter, fell in Sun Prairie.
A trained spotter reported large hail, measured to be 1 inch in diameter, that fell 1 mile northwest of Sun Prairie.
The public reported large hail, measured to be 1 inch in diameter, that fell 3 miles southeast of Marshall.
A trained spotter in Palmyra reported thunderstorm wind gusts estimated to be 60 mph (52 knots).
A trained spotter reported large hail, measured to be 1 inch in diameter, that fell 2 miles east of North Prairie.
The Walworth 911 Call Center received numerous reports of trees blown down by thunderstorm wind gusts estimated to be 65 mph (56 knots). A road was blocked by a fallen tree.
Law enforcement officials reported a tree blown down by thunderstorm wind gusts estimated to be 60 mph (52 knots) near the intersection of Big Bend Road and North Lake Drive.
The Racine 911 Call Center received reports of large trees blown down by thunderstorm wind gusts estimated to be 65 mph (56 knots) in the Caldwell area and in the Tichigan area west and north of Tichigan Lake. There were also reports of power lines arcing from damage due to the severe wind gusts.
A trained spotter reported large hail, estimated to be 1 inch in diameter, that fell 2 miles north of Racine. The hail damaged roofs and windows to several homes.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wisconsin in 2012Every state in 2012This day in weather historyWarnings in Wisconsin, July 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: 405845, 405846, 405847, 405848, 405854, 405851, 405860, 405855, 405858, 405852.