Several thunderstorms developed during the afternoon of Thursday, August 9th across west-central Wisconsin. The activity moved southeast and generated a few stronger storms, one of which produced quarter size hail, along with a swath of damage due to accompany strong winds across northern Dunn County near Ridgeland.
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 MPX wrote it up.
Several thunderstorms developed during the afternoon of Thursday, August 9th across west-central Wisconsin. The activity moved southeast and generated a few stronger storms, one of which produced quarter size hail, along with a swath of damage due to accompany strong winds across northern Dunn County near Ridgeland.
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 Twin Cities, MN wrote its last area forecast discussion before the first event at Aug 9, 5:10 AM CST, 7 hours 5 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 610 AM CDT THU AUG 9 2012 .UPDATED FOR 12Z AVIATION DISCUSSION BELOW... .DISCUSSION... UPSTREAM VORT NEARING THE ONTARIO BORDER WITH NE MN WILL BE THE MAIN WEATHER FEATURE FOR TODAY AS IT DROPS SE ACROSS NE MN THIS MRNG AND INTO CENTRAL WI BY EVENING. EARLIER CONVECTION IN N MN HAS WEAKENED BUT SHOULD BECOME MORE WIDESPREAD AGAIN LATE THIS MORNING AND AFTN AS AIRMASS SHOWS SOME DESTABILIZATION WITH WITH COLD CYCLONIC FLOW ALOFT. 500 MB TEMPS THIS AFTERNOON IN E PTNS OF AREA PROGGED TO BE IN THE B17 RANGE. CONTINUED WITH MID RANGE CHANCE POPS IN WI CWA WITH DIMINISHING POP CHANCES DIMINISHING TO SLIGHT CHANCE WEST OF MSP. WEAK INVERTED TROF NEAR MN/WI MAY HELP TO FOCUS TSTMS...BUT THIS FEATURE WEAKENS DURING THE DAY AS SURFACE HIGH PRESSURE BEGINS TO BUILD DOWN FROM CANADA. METARS AND 11-3.9 SATELLITE IMAGERY SHOWING RAPID EXPANSION OF IFR CIGS ACROSS SE MN INTO WI MAINLY NEAR THE INVERTED TROF WITH A NARROW RIBBON OF IFR FOG ACROSS CENTRAL MN BETWEEN THESE CLOUDS AND MID CLOUDS DROPPING OUT OF N MN. FOG WILL BE OF SHORT DURATION AS VSBYS HAVE BEEN IMPROVING AS MID CLOUDS MOVE IN FROM THE NORTH. TEMPS TODAY WILL SHOW A FAIRLY LARGE RANGE WITH HIGHS AROUND 70 IN MAINLY CLOUDY WI AREA GRADING TO AROUND 80 WEST. UPPER RIDGE BUILDS INTO AREA FOR FRIDAY AS COOL SURFACE HIGH PRESSURE CONTINUES EXPANDING S FROM ONTARIO INTO AREA. CONTINUED WITH MENTION OF FOG IN FORECAST FOR FRIDAY MORNING. RIDGE FLATTENS SATURDAY AS WEAK TROUGH COMES THRU SPREADING SOME SLIGHT CHANCE POPS INTO WC MN SATURDAY AFTERNOON. GFS/NAM/ECMWF IN FAIRLY GOOD AGREEMENT ON TIMING OF PCPN ACROSS AREA WITH WITH PCPN ACROSS ABOUT THE W 1/2 OF AREA BY 12Z SUNDAY...THEN SPREADING SE DURING THE DAY AS SFC LOW BEING CARRIED BY UPPER TROF ARRIVES IN S IA/N MO BY SUNDAY EVE. GFS AS HAS BEEN THE CASE FOR SOMETIME IS AGAIN CONSIDERABLY MORE AGGRESSIVE ON QPF OUTPUT. TEMPERATURES THRU MOST OF THE NEXT WEEK WILL RUN AT OR A BIT BELOW NORMAL IN NW FLOW UNTIL ABOUT TUESDAY AHEAD OF DEVELOPING UPSTREAM TROUGH AS WE RETURN TO A WARMER SOUTHERLY FLOW. GFS/ECMWF BOTH SUGGEST FAIRLY GOOD PCPN EVENT FOR THE MIDDLE OF NEXT WEEK. && .AVIATION.../12Z TAF ISSUANCE/ IFR/LIFR CIGS/VSBYS DEVELOPED ON THE BACKSIDE OF INITIAL DEPARTING VORT TO THE SOUTHEAST. FOG DEVELOPED IN CLEAR WEDGE AHEAD OF NEXT SHORT WAVE TO THE NORTHEAST. WILL HAVE TO HOLD ONTO STRATUS FOR AT LEAST A COUPLE HOURS AT MOST LOCATIONS...LONGEST TO THE EAST. BAND OF -SHRA ASSOCIATED WITH NEXT WAVE DROPPING OVER CENTRAL MN...CLEARING KAXN/KSTC NOW. LOW CLOUDS SHOULD MOVE OUT OF KSTC IN AN HOUR OR SO...THEN AS NEXT WAVE MOVES IN...EXPECTED AT LEAST BKN CEILING TO PERSIST THROUGH THE REST OF THE DAY. SHOULD SEE VFR CEILINGS DEVELOP BY 17Z ACROSS THE AREA. MENTIONED VCSH AT KMSP/KRNH AND VCTS AT KEAU AFTER 20Z PER LOCAL MODEL TRENDS. THIS MOVES OUT THROUGH 01Z AND EXPECT CLEARING CONDITIONS FROM WEST TO EAST. NORTH TO NORTHEAST WINDS TODAY. COULD SEE SOME GUSTS DEVELOP IN THE AFTERNOON...BUT CLOUDS SHOULD LIMIT THAT SOMEWHAT. AS SURFACE HIGH DROPS SOUTH TONIGHT...SHOULD SEE SKC MOST AREAS. DRIER AIR ASSOCIATED WITH THIS AIRMASS...SO DIDNT MENTION FOG. KMSP...STRATUS SHOULD LIFT IN A COUPLE HOURS LEAVING MVFR THROUGH LATE MORNING. EXPECT CUMULUS AROUND TODAY WITH SMALL THREAT OF SHRA THIS AM...AND A BETTER CHANCE OF BEING ON THE WESTERN EDGE OF ACTIVITY BY 20Z AS UPPER TROUGH DROPS ACROSS WISCONSIN. CLEARING EXPECTED AFTER 00Z WITH A FEW CUMULUS POSSIBLE AGAIN FRIDAY MORNING. NORTH/NORTHEAST WINDS TODAY...SHOULD REMAIN 10-12KNOTS OR LESS. OUTLOOK... .FRIDAY...VFR. WINDS E 5-10 KTS. .SATURDAY...VFR. SLIGHT CHANCE OF -SHRA/TSRA NEAR KRWF DURING THE AFTERNOON AND EVENING. WINDS SE 5-10 KTS. .SUNDAY...VFR. WINDS SE 5 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && BAP/DE
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 1106 AM CDT THU AUG 9 2012 MNZ045-052-053-061>063-070-078-WIZ014>016-023>028-101615- KANABEC-ISANTI-CHISAGO-ANOKA-RAMSEY-WASHINGTON-DAKOTA-GOODHUE- POLK-BARRON-RUSK-ST. CROIX-PIERCE-DUNN-PEPIN-CHIPPEWA-EAU CLAIRE- 1106 AM CDT THU AUG 9 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST CENTRAL MINNESOTA...SOUTHEAST MINNESOTA...NORTHWEST WISCONSIN AND WEST CENTRAL WISCONSIN. .DAY ONE...TODAY AND TONIGHT ISOLATED WEAK THUNDERSTORMS ARE EXPECTED THIS AFTERNOON ACROSS WEST CENTRAL WISCONSIN INTO EASTERN MINNESOTA. SEVERE STORMS ARE HIGHLY UNLIKELY. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY A FEW THUNDERSTORMS ARE POSSIBLE LATE THIS WEEKEND AND AGAIN DURING THE MIDDLE OF NEXT WEEK. THE THREAT FOR SEVERE WEATHER DURING THIS PERIOD IS LOW. .SPOTTER INFORMATION STATEMENT... SKYWARN SPOTTER ACTIVATION WILL NOT BE NEEDED. MNZ041>044-047>051-054>060-064>069-073>077-082>085-091>093-101615- DOUGLAS-TODD-MORRISON-MILLE LACS-STEVENS-POPE-STEARNS-BENTON- SHERBURNE-LAC QUI PARLE-SWIFT-CHIPPEWA-KANDIYOHI-MEEKER-WRIGHT- HENNEPIN-YELLOW MEDICINE-RENVILLE-MCLEOD-SIBLEY-CARVER-SCOTT- REDWOOD-BROWN-NICOLLET-LE SUEUR-RICE-WATONWAN-BLUE EARTH-WASECA- STEELE-MARTIN-FARIBAULT-FREEBORN- 1106 AM CDT THU AUG 9 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL MINNESOTA...EAST CENTRAL MINNESOTA...SOUTH CENTRAL MINNESOTA... SOUTHWEST MINNESOTA AND WEST CENTRAL MINNESOTA. .DAY ONE...TODAY AND TONIGHT NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY A FEW THUNDERSTORMS ARE POSSIBLE LATE THIS WEEKEND AND AGAIN DURING THE MIDDLE OF NEXT WEEK. THE THREAT FOR SEVERE WEATHER DURING THIS PERIOD IS LOW. .SPOTTER INFORMATION STATEMENT... SKYWARN SPOTTER ACTIVATION WILL NOT BE NEEDED.
The national radar mosaic for the moment the first event began.
2 hail. Local standard time, as filed.
Quarter size hail, and strong winds caused damage to both corn, and soy bean crops southwest of Ridgeland, Wisconsin. The corn and soy beans were completely stripped and flattened for a five mile long, and 1.5 mile wide path.
Quarter size hail was observed on Lake Pepin.
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, August 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: 391738, 394772.