Strong to severe thunderstorms moved across Lake Superior and Upper Michigan north of a warm front during the late afternoon and early evening hours. In northern Wisconsin, outflow from these storms caused damage and triggered addition thunderstorms that produced large hail.
Every event with a place to put it; 1 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 GRB wrote it up.
Strong to severe thunderstorms moved across Lake Superior and Upper Michigan north of a warm front during the late afternoon and early evening hours. In northern Wisconsin, outflow from these storms caused damage and triggered addition thunderstorms that produced large hail.
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 Green Bay, WI wrote its last area forecast discussion before the first event at Jul 4, 4:17 PM CST, 43 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREEN BAY WI 517 PM CDT WED JUL 4 2012 UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE .SYNOPSIS..HEAT WAVE TO CONTINUE FOR A COUPLE MORE DAYS...THEN AT LEAST A LITTLE COOLER FOR THE WEEKEND AND NEXT WEEK... MASSIVE UPR HIGH CREATING THE HEAT WAVE CONDITIONS ACRS THE MIDDLE OF THE COUNTRY WL RETROGRADE WWD INTO THE WRN PLAINS...THEN BUILD NWD ACRS THE CANADIAN ROCKIES NEXT WEEK. THAT WL EVENTUALLY TILT THE UPR FLOW ACRS THE FCST AREA NW. SO AFTER A COUPLE MORE DAYS OF EXTREME HEAT...TEMPS WL EDGE BACK CLOSER TO SEASONAL NORMALS. BEST CHC OF PCPN WL BE AS FRONTAL BOUNDARY LINGERS NEAR THE AREA EARLY IN THE FCST PERIOD...AND INTERACTS WITH THE HOT AND VERY HUMID AIR ACRS THE RGN. PCPN AMNTS WL DEPEND ON INDIVIDUAL CONVECTIVE SYSTEMS AND ARE TOUGH TO GAUGE...BUT SIG RAINS CERTAINLY POSSIBLE OVER AT LEAST PARTS OF THE FCST AREA. THE CHC FOR SIG PCPN WL END ONCE THE UPR FLOW TILTS NW LATE IN THE WEEKEND. && .SHORT TERM...TONIGHT AND THURSDAY. NEAR-TERM CONVECTIVE CHANCES STILL BEING MONITORED AS VERY HIGH INSTABILITY IS JUXTAPOSED WITH SUBTLE SURFACE BOUNDARY. ATMOSPHERE APPEARS TOO CAPPED...BUT ANY ISOLATED STORM THAT BREAKS CAP COULD BE STRONG. EYES THEN TURN TO CONVECTIVE CLUSTER OVER N MN LATE THIS AFTERNOON. THAT WOULD AFFECT NW PORTIONS OF FORECAST AREA AFTER 00Z. THIS COULD REMAIN SEVERE AS IT MOVES INTO NW WI GIVEN AFOREMENTIONED AXIS OF INSTABILITY. LITTLE CHANGE IN PREVIOUS FORECAST AS THURSDAY STILL APPEARS TO BE THE HOTTEST DAY OF PERIOD FOR MANY LOCATIONS...ESP EAST-CENTRAL. LONG- TERM PERIOD OF HIGH HEAT INDICES AND EXPECTED READINGS OVER 105 ON THURSDAY...SO UPGRADED TO HEAT WARNING. AGAIN...ANY CONVECTION THAT OCCURS OVERNIGHT WILL HAVE IMPACT ON LOCATION OF BOUNDARIES AND RESULTANT CLOUDS AND TEMPS. ADDITIONALLY...WEAK FRONTAL BOUNDARY WILL DRIFT SOUTH ACROSS AREA AS SURFACE HIGH PRESSURE NOSES INTO WESTERN LAKES. FRONT COULD BE FOCUS FOR ADDITIONAL STORMS...THOUGH ATMOSPHERE WILL AGAIN BE CAPPED. .LONG TERM...THU NGT THROUGH NEXT WED. HARD TO GET A GOOD HANDLE ON PCPN CHCS...BUT NEED TO KEEP CHC GOING UNTIL THE FRONT FINALLY GETS SHOVED S OF THE AREA THIS WEEKEND. THE POTENTIAL CERTAINLY EXISTS FOR EXCESSIVE RAINFALL AT SOME LOCATIONS GIVEN THE AVAILABLE MOISTURE. QUIETER WX TO RETURN NEXT WEEK UNDER NWLY UPR FLOW. BUT TEMPS WL PROBABLY STILL END UP NR OR A LITTLE ABV NORMAL...AT LEAST FOR AFTN HIGHS. && .AVIATION...AT 23Z WEDNESDAY...A SUBTLE SURFACE BOUNDARY LINGERS OVER NORTHEAST WISCONSIN AND EXTENDED INTO LOWER MICHIGAN. ISOLATED SHOWERS AND STORMS HAVE ALREADY DEVELOPED ALONG THE BOUNDARY LATE THIS AFTERNOON. CONVECTION IS JUGGLING BETWEEN A HEALTHY CAP WITH VERY UNSTABLE AIR. ONGOING CONVECTION OVER UPPER MICHIGAN WILL NEED TO BE MONITORED THIS EVENING WITH RESPECT TO DEVELOPING SOUTHEASTWARD ALONG THIS BOUNDARY. AS A RESULT ISOLDE MVFR CIGS AND IFR VSBYS POSSIBLE OVER NORTHEAST WISCONSIN. OTHERWISE BESIDES PATCHY FOG OVER NORTHERN WISCONSIN...VFR CONDITIONS TO PREVAIL. VIS LOOP THE LAST FEW DAYS INDICATE SOME SMOKE FROM THE WESTERN FIRES MAY PRODUCE SOME LOWER END VFR VSBYS THROUGH THURSDAY. TDH && .GRB WATCHES/WARNINGS/ADVISORIES... EXCESSIVE HEAT WARNING UNTIL 10 PM CDT FRIDAY FOR WIZ030-031- 035>040-045-048>050. HEAT ADVISORY UNTIL 10 PM CDT THURSDAY FOR WIZ018>021-073-074. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GREEN BAY WI 315 PM CDT WED JUL 4 2012 WIZ005-010>013-018>022-030-031-035>040-045-048>050-073-074-052015- VILAS-ONEIDA-FOREST-FLORENCE-NORTHERN MARINETTE-LINCOLN-LANGLADE- MENOMINEE-NORTHERN OCONTO-DOOR-MARATHON-SHAWANO-WOOD-PORTAGE- WAUPACA-OUTAGAMIE-BROWN-KEWAUNEE-WAUSHARA-WINNEBAGO-CALUMET- MANITOWOC-SOUTHERN MARINETTE-SOUTHERN OCONTO- 315 PM CDT WED JUL 4 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL AND NORTHEAST WISCONSIN. .DAY ONE...TONIGHT THERE IS A CHANCE OF THUNDERSTORMS TONIGHT...ESPECIALLY OVER NORTHERN WISCONSIN. ANY STORMS THAT DEVELOP COULD PRODUCE HEAVY RAINFALL AND STRONG WINDS. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH WEDNESDAY THE HEAT WAVE WILL PERSIST FOR THE REST OF THE WEEK...CREATING POTENTIALLY DANGEROUS CONDITIONS FOR ANYONE ENGAGED IN STRENUOUS OUTDOOR ACTIVITIES. THE HOTTEST TEMPERATURES ARE EXPECTED ON THURSDAY...WHEN AIR TEMPERATURES WILL REACH 100 DEGREES IN PARTS OF CENTRAL AND EAST CENTRAL WISCONSIN...AND HEAT INDICES COULD REACH 110. THERE IS A CHANCE OF THUNDERSTORMS ACROSS THE ENTIRE AREA FROM TIME TO TIME THROUGH FRIDAY NIGHT...WITH THE THREAT CONTINUING INTO THE WEEKEND OVER CENTRAL AND EAST-CENTRAL WISCONSIN. GIVEN THE HUMID CONDITIONS ACROSS THE AREA...ANY OF THE STORMS COULD PRODUCE TORRENTIAL RAINS. ALTHOUGH AN ENHANCED RISK OF SEVERE WEATHER MAY OCCUR AT SOME POINT...IT IS NOT YET POSSIBLE TO PIN- POINT WHEN THAT WOULD OCCUR. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED TONIGHT OVER MAINLY THE NORTH. LMZ521-522-541>543-052015- THE BAY OF GREEN BAY SOUTH OF A LINE FROM CEDAR RIVER MI TO ROCK ISLAND PASSAGE-LAKE MICHIGAN FROM WASHINGTON ISLAND TO SHEBOYGAN- 315 PM CDT WED JUL 4 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHWEST LAKE MICHIGAN AND THE WATERS OF GREEN BAY. .DAY ONE...TONIGHT THERE IS A SLIGHT CHANCE OF THUNDERSTORMS TONIGHT. ANY STORMS THAT DEVELOP COULD PRODUCE HEAVY RAINFALL AND GUSTY WINDS. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH WEDNESDAY THERE IS A CHANCE OF THUNDERSTORMS FROM TIME TO TIME THROUGH THE WEEKEND. GIVEN THE HOT AND HUMID CONDITIONS ACROSS THE AREA...ANY OF THE STORMS COULD PRODUCE TORRENTIAL RAINS. ALTHOUGH AN ENHANCED RISK OF SEVERE WEATHER MAY OCCUR AT SOME POINT...IT IS NOT YET POSSIBLE TO PIN-POINT WHEN THAT WOULD OCCUR. PATCHY DENSE FOG IS POSSIBLE AT TIMES THROUGH THE END OF THE WEEK...ESPECIALLY OVER THE LAKE. JKL/JS
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE GREEN BAY WI 437 PM CDT WED JUL 4 2012 WIZ011-012-042245- FLORENCE-FOREST- 437 PM CDT WED JUL 4 2012 ...STRONG THUNDERSTORM MOVING INTO FLORENCE COUNTY... AT 430 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A STRONG THUNDERSTORM OVER CENTRAL FOREST COUNTY...MOVING EAST AT 15 MPH INTO FLORENCE COUNTY. UP TO ONE HALF INCH DIAMETER HAIL...WINDS GUSTS TO 30 MPH...OCCASIONAL CLOUD TO GROUND LIGHTNING...AND BRIEF MODERATE DOWNPOURS WILL BE POSSIBLE WITH THIS STORM. * THE THUNDERSTORM WILL BE NEAR... FLORENCE BY 545 PM CDT... GUSTY WINDS MAY CAUSE LIGHT WEIGHT OBJECTS TO BE BLOWN OVER. STAY AWAY FROM HIGH OBJECTS OUTDOORS SUCH AS TREES. SEEK SHELTER IN A STURDY STRUCTURE UNTIL THIS STORM HAS PASSED. TH
The Marquette radar (KMQT), 160 km away, was scanning. The volume nearest the first event began at 23:47 UTC.
1 strong wind, 1 hail. Local standard time, as filed.
Strong outflow from storms that moved across Lake Superior and western Upper Michigan downed several trees and power lines in Eagle River and Presque Isle.
Thunderstorms produced quarter size hail north of Fence.
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: 404158, 401661.