Thunderstorms developed in an unstable air mass north of a warm front. Some of the storms became quite strong as they moved through central and east central Wisconsin, producing hail up to nickel size, heavy rainfall and isolated wind damage.
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 GRB wrote it up.
Thunderstorms developed in an unstable air mass north of a warm front. Some of the storms became quite strong as they moved through central and east central Wisconsin, producing hail up to nickel size, heavy rainfall and isolated wind damage.
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 May 26, 4:51 PM CST, 3 hours 39 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREEN BAY WI 551 PM CDT SAT MAY 26 2012 UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE .SHORT TERM...MODELS IN POOR AGREEMENT WITH RESPECT TO AREAL EXTENT AND TIMING OF OVERNIGHT CONVECTION ASSOCIATED WITH WARM FRONT. 26/12Z NAM IS FARTHEST OUTLIER AND DISREGARDED FOR THIS FORECAST. IN THE NEAR-TERM...DECAYING MCS PRODUCING SHOWERS ACROSS CENTRAL WI. ADDITIONAL STORMS WERE FORMING IN E MN ASSOCIATED WITH STRONG LOW-LEVEL WARM AIR ADVECTION AND DIFFLUENT UPPER FLOW. THIS AREA COULD FORM INTO ANOTHER MCS WHICH WOULD MOVE ACROSS THE FORECAST AREA. MCS WOULD RETARD NORTHWARD MOVEMENT OF WARM FRONT SOMEWHAT WHICH WILL HAVE SIGNIFICANT IMPACT ON SUNDAY MAX TEMPS IN THE NORTH. ELEVATED INSTABILITY WOULD SUGGEST THAT NEAR SEVERE HAIL NOT OUT OF THE QUESTION WITH STRONGER STORMS OVERNIGHT. LOCAL HEAVY RAIN ALSO EXPECTED WITH MODERATELY-HIGH PWATS ACROSS REGION. TEMPS TONIGHT A BLEND OF BIAS CORRECTED MODEL GUIDANCE. MAX FORECAST TEMPS FOR SUNDAY IN THE SOUTH A BIT HIGHER THAN GUIDANCE...HOWEVER THE NORTH WILL BE HIGHLY DEPENDENT ON CLOUD DEBRIS AND WARM FRONT POSITION. .LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY...THE MAIN FCST CONCERN IS THE THREAT OF SEVERE TSTMS ON MEMORIAL DAY. A STRONG CAPPING INVERSION SHOULD BE IN PLACE SUNDAY EVG...BUT H7 CAA SHOULD ERODE THAT OVERNIGHT...AND MAY ALLOW A FEW STORMS TO WORK INTO OUR NW COUNTIES LATE. A COLD FRONT WILL MAKE ITS WAY THROUGH GRB CWA ON MEMORIAL DAY. ALTHOUGH CAPES ARE EXPECTED TO INCREASE NEAR 2000 J/KG IN ADVANCE OF THE FRONT...AND DEEP LAYER SHEAR WILL BE ADEQUATE FOR SUPERCELL DEVELOPMENT...HAVE SOME CONCERNS ABOUT RELATIVELY WEAK LOW- LEVEL WIND FIELDS AND CONVERGENCE. STILL BELIEVE THAT SPC SLGT RISK IS WARRANTED...BUT COVERAGE OF STORMS MAY BE LESS THAN PREVIOUSLY THOUGHT...SO HAVE LOWERED POPS A LITTLE BIT. KEPT HIGHEST POPS IN EC WI...WHERE THE FRONT IS EXPECTED TO PASS DURING PEAK HEATING. THIS WOULD ALSO APPEAR TO BE THE AREA WITH THE GREATEST LIKELIHOOD OF SVR TSTMS. HAVE KEPT SMALL POPS IN PLACE FOR THE EVG HOURS...BUT A DRY SLOT AND THE DEPARTURE OF THE COLD FRONT SHOULD BRING A FAIRLY QUICK END TO THE PCPN. MUCH COOLER AIR WILL ARRIVE MONDAY NIGHT INTO TUESDAY...WITH MAX TEMPS EXPECTED TO BE ABOUT 15 DEGREES LOWER THAN MONDAY. SOME LIGHT WRAP- AROUND SHOWERS MAY IMPACT NC/FAR NE WI. EXPECT STRATOCUMULUS TO OVERSPREAD MUCH OF THE AREA DURING THE DAY...WITH CONDITIONS RANGING FROM PARTLY SUNNY SE TO CLOUDY NORTHWEST. EVEN COOLER CONDITIONS ARE ANTICIPATED ON WEDNESDAY...AS H8 TEMPS DROP TO AROUND ZERO C OVER NORTHERN WI. ISOLD/SCT SHOWERS MAY CONTINUE AS AN UPPER TROF MOVES THROUGH. LOOK FOR A GENERALLY DRY PERIOD FOR THE MID TO LATE PART OF THE WEEK...AS CANADIAN HIGH PRESSURE DOMINATES OUR WEATHER. TEMPERATURES WILL GRADUALLY MODERATE TO NEAR NORMAL LATE IN THE WEEK. && .AVIATION...GETTING WIND GUSTS TO 40 MPH OVER PARTS OF CENTRAL WISCONSIN FOR POSSIBLE SECOND WAKE LOW FEATURE PASSING OVER. REPORT OF 40 MPH WIND GUSTS AT SCANDINAVIA IN WAUPACA COUNTY WHILE THE WAUPACA OBSERVATIONS REPORTS GUSTY WINDS FROM THE SOUTH. WILL ADD A 2-3 HOUR WINDOW OF GUSTY SOUTH WINDS TO THE GRB AND ATW TAFS THIS EVENING TO ACCOUNT FOR THIS WEATHER FEATURE. OTHERWISE AREAS OF MVFR CIGS AND VSBYS WITH SHOWERS AND STORMS WILL CONTINUE OVER CENTRAL AND EAST CENTRAL THIS EVENING AND SPREAD INTO NORTHERN WISCONSIN OVERNIGHT AS PRECIPITATION BECOMES MORE WIDESPREAD. SCATTERED MVFR CIGS AND VSBYS DUE TO SHOWERS AND STORMS MAY LINGER SUNDAY MORNING OVER NORTHERN WISCONSIN BEFORE VFR CONDITIONS TO DOMINATE LATER SUNDAY. TDH && .CLIMATE...SEVERAL RECORD HIGHS MAY BE BROKEN ON SUNDAY. LIST OF RECORDS HIGHS THAT MAY BE REACHED OR EXCEEDED FOR MAY 27 ARE BELOW: GREEN BAY.... 89 APPLETON..... 90 OSHKOSH...... 90 WAUSAU....... 88 MARSHFIELD... 90 WI RAPIDS.... 92 STEVENS PT... 92 && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GREEN BAY WI 300 PM CDT SAT MAY 26 2012 WIZ005-010>013-018>022-030-031-035>040-045-048>050-073-074-272000- 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- 300 PM CDT SAT MAY 26 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL AND NORTHEAST WISCONSIN. .DAY ONE...TONIGHT THUNDERSTORMS ARE LIKELY TONIGHT. SOME THUNDERSTORMS COULD PRODUCE LOCALLY HEAVY RAIN AND HAIL...BUT WIDESPREAD SEVERE WEATHER IS NOT EXPECTED. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH SATURDAY THERE IS CHANCE OF THUNDERSTORMS ACROSS NORTHERN WISCONSIN ON SUNDAY MORNING...BUT WIDESPREAD SEVERE WEATHER IS NOT ANTICIPATED. SCATTERED THUNDERSTORMS ARE EXPECTED ON MEMORIAL DAY...AS A COLD FRONT MOVES ACROSS THE AREA. THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS WITH DAMAGING WINDS AND LARGE HAIL. THE GREATEST THREAT IS EXPECTED ACROSS NORTHEAST AND EAST CENTRAL WISCONSIN DURING THE MID TO LATE AFTERNOON. MUCH COOLER AIR WILL ARRIVE DURING THE MIDDLE OF THE WEEK AFTER THE COLD FRONT GOES BY. FROST IS POSSIBLE IN THE NORTH THURSDAY MORNING. .SPOTTER INFORMATION STATEMENT... FORMAL SPOTTER ACTIVATION IS UNLIKELY TONIGHT...BUT SPOTTERS ARE ENCOURAGED TO CONTACT THE NATIONAL WEATHER SERVICE WITH REPORTS OF HAIL. LMZ521-522-541>543-272000- THE BAY OF GREEN BAY SOUTH OF A LINE FROM CEDAR RIVER MI TO ROCK ISLAND PASSAGE-LAKE MICHIGAN FROM WASHINGTON ISLAND TO SHEBOYGAN- 300 PM CDT SAT MAY 26 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHWEST LAKE MICHIGAN AND THE WATERS OF GREEN BAY. .DAY ONE...TONIGHT THUNDERSTORMS ARE LIKELY TONIGHT...SOME POSSIBLY STRONG...WITH HAIL AND HEAVY RAINFALL. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH SATURDAY THERE IS A CHANCE OF THUNDERSTORMS ON SUNDAY MORNING...ESPECIALLY NORTH OF STURGEON BAY. WIDESPREAD SEVERE WEATHER IS NOT ANTICIPATED. THUNDERSTORMS ARE EXPECTED ON MEMORIAL DAY. A FEW OF THE STORMS MAY BE STRONG TO SEVERE DURING THE LATE AFTERNOON AND EARLY EVENING...WITH STRONG WINDS AND HAIL THE MAIN THREATS. JKL/TSK
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE GREEN BAY WI 832 PM CDT SAT MAY 26 2012 WIZ035-270230- WOOD- 832 PM CDT SAT MAY 26 2012 ...STRONG TO SEVERE STORM MOVING TOWARD WOOD COUNTY... AT 823 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A STRONG THUNDERSTORM OVER JACKSON COUNTY...MOVING NORTHEAST AT 30 MPH. THIS STORM IS CAPABLE OF PRODUCING UP TO QUARTER SIZE HAIL...WINDS 40 TO 45 MPH...FREQUENT CLOUD TO GROUND LIGHTNING...HEAVY DOWNPOURS...ARE POSSIBLE WITH THIS STORM. * THE THUNDERSTORM WILL BE NEAR... BABCOCK BY 900 PM CDT... WISCONSIN RAPIDS BY 925 PM CDT... GUSTY WINDS MAY CAUSE SMALL OBJECTS SUCH AS TRASH BINS TO BLOW AROUND. STAY AWAY FROM HIGH OBJECTS OUTDOORS SUCH AS TREES. SEEK SHELTER IN A STURDY STRUCTURE UNTIL THIS STORM HAS PASSED. BERSCH
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE GREEN BAY WI 923 PM CDT SAT MAY 26 2012 WIZ045-270315- WAUSHARA- 923 PM CDT SAT MAY 26 2012 ...STRONG THUNDERSTORMS MOVING INTO WAUSHARA COUNTY... AT 918 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED STRONG THUNDERSTORMS ACROSS ADAMS COUNTY...MOVING EAST AT 35 MPH. NICKEL SIZE HAIL...WINDS 40 TO 45 MPH...FREQUENT CLOUD TO GROUND LIGHTNING...BRIEF HEAVY DOWNPOURS...ARE POSSIBLE WITH THESE STORMS. LOCATIONS IMPACTED INCLUDE... COLOMA... RICHFORD... HANCOCK... PLAINFIELD... WAUTOMA... SILVER LAKE... WILD ROSE... SPRING LAKE... MOUNT MORRIS... REDGRANITE... LOHRVILLE... PINE RIVER... WEST BLOOMFIELD... POY SIPPI... BORTH... GUSTY WINDS MAY CAUSE SMALL OBJECTS SUCH AS TRASH BINS TO BLOW AROUND. STAY AWAY FROM HIGH OBJECTS OUTDOORS SUCH AS TREES. SEEK SHELTER IN A STURDY STRUCTURE UNTIL THESE STORMS HAVE PASSED. BERSCH
The Green Bay radar (KGRB), 172 km away, was scanning. The volume nearest the first event began at 02:28 UTC.
4 hail, 2 heavy rain, 1 thunderstorm wind. Local standard time, as filed.
A weather observer north of Tomahawk, near Rice Reservoir, measured 3.55 inches of rain from storms that moved through the area between about 9:30 PM CDT on the 26th and 2:00 AM CDT on the 27th.
A spotter measured 2.60 inches of rain from thunderstorms that moved through the Heafford Junction area between about 10:00 PM CDT on the 26th and 2:18 AM CDT on the 27th.
A spotter observed nickel size hail near Marshfield as thunderstorms passed through the area.
Thunderstorm winds downed power lines as the storms moved through Marshfield.
Thunderstorms produced nickel size hail and winds of at least 55 mph as they passed through Auburndale.
Nickel size hail was observed with thunderstorms that moved through the Rib Mountain area.
A spotter observed penny size hail on the southwest side of Oshkosh.
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, May 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: 381974, 381971, 381968, 381972, 384778, 381969, 381970.