Strong and gusty winds developed as an area of weakening showers and thunderstorms moved away from the region. The high winds, a result of a wake low, downed numerous trees and power lines.
Every event with a place to put it; 3 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 and gusty winds developed as an area of weakening showers and thunderstorms moved away from the region. The high winds, a result of a wake low, downed numerous trees and power lines. Thousands of customers were without power across northern Wisconsin and nearly 9,000 customers lost power in Wausau (Marathon County). Trees on power lines caused some fires and an uprooted tree severed a gas line. Roofs were torn from two machine sheds near Antigo (Langlade County) and an unoccupied mobile home and a car were destroyed.
The highest measured wind gust was 65 mph in Weston (Marathon County), and a gust to 61 mph was recorded at Wausau Municipal Airport. The highest estimated gusts were 65 mph near Antigo and 60 mph near Sayner (Vilas County).
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 9, 3:04 AM CST, 10 hours 11 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREEN BAY WI 404 AM CDT MON MAY 9 2011 .SHORT TERM...THE COMBINATION OF A WEAK UPPER TROUGH AND LOW LEVEL WARM ADVECTION IS PRODUCING AN AREA OF SHOWERS AND THUNDERSTORMS ACROSS MINNESOTA AT 09Z. 850-500MB Q VECTORS DO A GREAT JOB DEPICTING THE ACTIVITY. THEY SUGGEST THAT THE CONVECTION WILL MOVE INTO WESTERN WISCONSIN THIS MORNING AND INTO THE EASTERN PART OF THE FORECAST AREA DURING THE AFTERNOON. THINK BEST CHANCE OF RAIN IS DURING THE AFTERNOON IN THE WESTERN COUNTIES AND IN THE EAST DURING THE EVENING HOURS. TUESDAY SHOULD BE CLOUDY AND MAINLY DRY WITH LITTLE IN THE WAY OF SUPPORT FOR PRECIPITATION. WHATEVER THEIR MIGHT BE WOULD BE ELEVATED AS LOW CLOUDS AND A SOUTHEAST WIND FROM LAKE MICHIGAN SHOULD KEEP THE LOW LEVELS STABLE. .LONG TERM...TUESDAY NIGHT THROUGH FRIDAY NIGHT. THE MAIN FORECAST CONCERNS DURING THIS PERIOD CONTINUE TO REVOLVE AROUND A WESTERN CONUS TROUGH PROGGED TO WEAKEN AS IT MOVES OVER THE CENTRAL PART OF THE COUNTRY LATER THIS WEEK. LIKE THE SEVERAL PAST DAYS...THE GFS CONTINUES TO SHOW A FASTER SOLUTION THAN THE ECMWF/GEM/NAM IN REGARDS TO THE TROUGH EMERGING OUT OF THE SOUTHWEST AND INTO THE PLAINS DURING THE MIDDLE OF THIS WEEK. WILL STAY WITH THE NAM/ECMWF SOLUTION FOR THIS FORECAST. TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...BROAD AREA OF LOW PRESSURE WILL EXTEND THROUGH THE GREAT PLAINS AND A SURFACE WARM FRONT WILL EXTEND ACROSS FAR SW WISCONSIN AND NORTHERN ILLINOIS TUESDAY NIGHT. ALTHOUGH THE SURFACE FRONT WILL REMAIN NEARLY STATIONARY...BOTH THE NAM AND ECMWF INDICATE A SURGE OF 900-800MB MOISTURE AND INSTABILITY THAT ERODES THE CAP COMPLETELY DURING THE LATE EVENING AND INTO THE OVERNIGHT HOURS. WITH ELEVATED CAPE VALUES OF 2K-3K J/KG AND WET BULB ZERO HEIGHTS UNDER 10KFT...SEE POTENTIAL FOR STRONG STORMS THAT COULD PRODUCE LARGE HAIL OVER CENTRAL AND EAST-CENTRAL WISCONSIN. LESS INSTABILITY WILL EXIST FARTHER NORTH...BUT STILL RESPECTABLE AT 1K-2K J/KG. WITH STEEP MID-LEVEL LAPSE RATES OF 7-8 C/KM...HAVE PLENTY OF INSTABILITY IN THE HAIL GROWTH ZONE OVER N-C WISCONSIN. BULK SHEAR VALUES OF AROUND 25 KTS AND A STRONG INVERSION WOULD SUGGEST A MINIMAL THREAT FOR DAMAGING WINDS. WILL INCREASE PRECIP CHANCES. THE SURFACE WARM FRONT WILL TRY TO MAKE SOME PROGRESS NORTHWARDS ON WEDNESDAY...BUT WEAKENING WIND FIELDS WILL MAKE IT SLOW GOING. PERHAPS IT COULD REACH INTO CENTRAL WISCONSIN IN THE AFTERNOON BUT MODELS INSIST THAT THE LIGHT EAST FLOW WILL KEEP IT SOUTH OF NE WISCONSIN. AS A RESULT OF THE WEAKENING WIND FIELDS...MOISTURE CONVERGENCE DIMINISHES ALONG THE FRONT ON WEDNESDAY...AND SO WILL INSTABILITY. BOTH THE NAM/ECMWF INDICATE A WEAK WAVE MOVING NORTH INTO THE NORTHERN MISSISSIPPI VALLEY LATE WEDNESDAY AFTERNOON AND WEDNESDAY EVENING THAT COULD HELP REIGNITE THE WARM FRONT. MUCH OF WEDNESDAY MAY BE DRY IF THIS OCCURS. WILL KEEP THE HIGH CHANCES OF PRECIP GOING FOR WEDNESDAY NIGHT. THURSDAY AND FRIDAY...THE SOUTHWEST CONUS SHORTWAVE WILL CLOSE OFF AS IT MEANDERS EAST ACROSS THE CENTRAL GREAT PLAINS AND INTO THE MID-MISSISSIPPI VALLEY. WITH SLOW MID-LEVEL HEIGHT FALLS TAKING PLACE OVER THE WESTERN GREAT LAKES AND THE LINGERING WARM FRONT OVER OR NEAR THE FORECAST AREA...HAVE TO KEEP PRECIP CHANCES IN THE FORECAST OVER THIS PERIOD. TEMPERATURES WILL REMAIN AT OR ABOVE NORMAL DESPITE THE PRECIP CHANCES. && .AVIATION...VFR CONDITIONS EXPECTED FOR MOST OF THE DAY WITH MIDDLE AND HIGH CLOUDS. AN AREA OF SHOWERS AND THUNDERSTORMS MAY ARRIVE ALONG A AUW TO RHI LINE IN THE AFTERNOON WITH MVFR CIGS AND VSBYS IF THEY OCCUR. CIGS AND VSBYS WILL BE LOWERING TONIGHT IN ANY SHOWER AND THUNDERSTORM ACTIVITY THAT OCCURS AND AS MOIST AIR FLOWS OVER THE COOL WATERS OF LAKE MICHIGAN. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && RDM/MPC
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GREEN BAY WI 1154 AM CDT MON MAY 9 2011 WIZ005-010>013-018>022-030-031-035>040-045-048>050-073-074-101700- 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- 1154 AM CDT MON MAY 9 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL AND NORTHEAST WISCONSIN. .DAY ONE...THIS AFTERNOON AND TONIGHT GUSTY EAST WINDS ARE EXPECTED TO DEVELOP IN NORTH CENTRAL AND CENTRAL WISCONSIN THIS AFTERNOON. THE GUSTS MAY EXCEED 40 MPH AT SOME LOCATIONS...POSSIBLY CAUSING MINOR TREE DAMAGE. THE WINDS MAY ALSO MAKE TRAVEL DIFFICULT FOR HIGH PROFILE VEHICLES...ESPECIALLY ON NORTH TO SOUTH ORIENTED ROADS. THERE IS A CHANCE OF THUNDERSTORMS ACROSS THE ENTIRE FORECAST AREA THIS AFTERNOON AND TONIGHT. ISOLATED STRONG THUNDERSTORMS WITH HAIL CAN BE EXPECTED...BUT WIDESPREAD SEVERE WEATHER IS NOT ANTICIPATED. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY PERIODS OF THUNDERSTORMS ARE EXPECTED ACROSS THE ENTIRE FORECAST AREA FROM TUESDAY THROUGH THURSDAY NIGHT. CLOUD COVER AND WEAK WIND SHEAR MAY LIMIT THE SEVERE THREAT DURING THIS PERIOD...BUT ISOLATED SEVERE THUNDERSTORMS WITH LARGE HAIL ARE POSSIBLE AT TIMES. .SPOTTER INFORMATION STATEMENT... SPOTTER GROUP ACTIVATION SHOULD NOT BE NEEDED THIS AFTERNOON OR TONIGHT...BUT SPOTTERS ARE STILL URGED TO RELAY ANY REPORTS OF HAIL OR WIND GUSTS OF 40 MPH OR HIGHER. LMZ521-522-541>543-101700- THE BAY OF GREEN BAY SOUTH OF A LINE FROM CEDAR RIVER MI TO ROCK ISLAND PASSAGE-LAKE MICHIGAN FROM WASHINGTON ISLAND TO SHEBOYGAN- 1154 AM CDT MON MAY 9 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHWEST LAKE MICHIGAN AND THE WATERS OF GREEN BAY. .DAY ONE...THIS AFTERNOON AND TONIGHT THERE IS A CHANCE OF THUNDERSTORMS TONIGHT...BUT SEVERE WEATHER IS NOT ANTICIPATED. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY THERE IS A CHANCE OF THUNDERSTORMS FROM TUESDAY THROUGH THURSDAY NIGHT. KIECKBUSCH
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE GREEN BAY WI 1254 PM CDT MON MAY 9 2011 WIZ005-010-018-019-030-035-036-092000- VILAS-ONEIDA-LINCOLN-LANGLADE-MARATHON-WOOD-PORTAGE- INCLUDING THE CITIES OF...EAGLE RIVER...RHINELANDER...TOMAHAWK... ANTIGO...WAUSAU...WISCONSIN RAPIDS...STEVENS POINT 1254 PM CDT MON MAY 9 2011 ...STRONG GUSTY EAST WINDS EXPECTED TO DEVELOP EARLY THIS AFTERNOON... GUSTY EAST WINDS HAVE DEVELOPED OVER NORTHWEST AND WEST CENTRAL WISCONSIN...IN THE WAKE OF A WEAKENING THUNDERSTORM COMPLEX. THE WINDS...WHICH ARE GUSTING OVER 50 MPH IN SOME AREAS...ARE EXPECTED TO SPREAD INTO NORTH CENTRAL AND CENTRAL WISCONSIN BETWEEN 1 PM AND 2 PM. THE STRONG GUSTY WINDS ARE ONLY EXPECTED TO LAST FOR A HALF HOUR OR SO AT ANY GIVEN LOCATION...BUT MAY BE STRONG ENOUGH TO CAUSE TREE DAMAGE. THE WINDS WILL ALSO MAKE TRAVEL HAZARDOUS FOR HIGH PROFILE VEHICLES...ESPECIALLY ON NORTH TO SOUTH ORIENTED ROADS. PERSONS IN NORTH CENTRAL AND CENTRAL WISCONSIN SHOULD BE ALERT FOR STRONG GUSTY EAST WINDS THROUGH MID-AFTERNOON. THOSE WITH OUTDOOR PLANS SHOULD BE PREPARED TO SEEK SHELTER INDOORS. KIECKBUSCH
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE GREEN BAY WI 203 PM CDT MON MAY 9 2011 WIZ005-010-011-018>020-030-031-035>037-045-092130- VILAS-ONEIDA-FOREST-LINCOLN-LANGLADE-MENOMINEE-MARATHON-SHAWANO- WOOD-PORTAGE-WAUPACA-WAUSHARA- INCLUDING THE CITIES OF...EAGLE RIVER...RHINELANDER...CRANDON... TOMAHAWK...ANTIGO...KESHENA...WAUSAU...WISCONSIN RAPIDS... STEVENS POINT...WAUTOMA 203 PM CDT MON MAY 9 2011 ...STRONG GUSTY EAST WINDS OCCURRING OVER CENTRAL AND NORTH CENTRAL WISCONSIN THIS AFTERNOON... GUSTY EAST WINDS HAVE DEVELOPED OVER CENTRAL AND NORTH CENTRAL WISCONSIN...IN THE WAKE OF A WEAKENING THUNDERSTORM COMPLEX. THE WINDS...WHICH ARE GUSTING TO 35 TO 50 MPH IN MOST AREAS...ARE EXPECTED TO SPREAD EAST AND GRADUALLY WEAKEN DURING THE AFTERNOON. SO FAR...THE PEAK GUST IN THE GREEN BAY FORECAST AREA HAS BEEN 52 MPH AT MARSHFIELD. THE STRONG GUSTY WINDS ARE EXPECTED TO LAST FOR ABOUT AN HOUR AT ANY GIVEN LOCATION...AND MAY BE STRONG ENOUGH TO CAUSE TREE DAMAGE. THE WINDS WILL ALSO MAKE TRAVEL HAZARDOUS FOR HIGH PROFILE VEHICLES...ESPECIALLY ON NORTH TO SOUTH ORIENTED ROADS. PERSONS IN CENTRAL...NORTH CENTRAL AND PARTS OF NORTHEAST WISCONSIN SHOULD BE ALERT FOR STRONG GUSTY EAST WINDS THIS AFTERNOON. THOSE WITH OUTDOOR PLANS SHOULD SEEK SHELTER WHEN THE WINDS INCREASE. KIECKBUSCH
The national radar mosaic for the moment the first event began.
3 high wind. Local standard time, as filed.
Estimated wind gusts to 60 mph near Sayner knocked down trees and power lines. Thousands in the area were left without power.
Wind gusts as high as 65 mph in Weston and 61 mph at the Wausau Municipal Airport downed numerous trees and power lines in the area. Around 9,000 people in Wausau lost power. An uprooted tree broke a gas line and trees on power lines started some fires in the area.
Wind gusts estimated to 65 mph downed trees and tore the roofs from two machine sheds northwest of Antigo. Trees fell on an unoccupied mobile home and a car, heavily damaging both.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Wisconsin in 2011Every state in 2011This day in weather historyWarnings in Wisconsin, May 2011
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: 314117, 314118, 314119.