Severe thunderstorms produced damaging winds during the morning hours of September 2nd across portions of southeast Minnesota. Winds of 60 mph or greater occurred in a swath from southeast Mower County through Fillmore County into Winona and Houston Counties.
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 ARX wrote it up.
Severe thunderstorms produced damaging winds during the morning hours of September 2nd across portions of southeast Minnesota. Winds of 60 mph or greater occurred in a swath from southeast Mower County through Fillmore County into Winona and Houston Counties. Numerous trees and power lines were blown down in this damage area from Lyle (Mower County) to near Brownsville (Houston 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 La Crosse, WI wrote its last area forecast discussion before the first event at Sep 2, 1:30 AM CST, 3 hours 25 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 230 AM CDT FRI SEP 2 2011 .SHORT TERM...TODAY THROUGH SUNDAY NIGHT FORECAST CONCERNS FOCUS ON THE STORM THREAT OVER THE NEXT COUPLE DAYS...THEN MUCH COOLER AIR FOR THE END OF THE WEEKEND. THUNDERSTORMS CONTINUE TO SPARK OVER THE CENTRAL/NORTHERN PLAINS EARLY THIS MORNING...AHEAD OF AN UPPER LEVEL SHORTWAVE TROUGH DRIVING ACROSS THE WESTERN DAKOTAS //PER WATERVAPOR SATELLITE IMAGERY//. AT THE SFC A FRONT RAN FROM THE MN ARROWHEAD SOUTHEAST INTO NEB. THIS SHORTWAVE TROUGH WILL CONTINUE ITS EASTWARD TRACK TODAY...KEEPING THE BULK OF THE ITS ENERGY TO THE NORTH. THE TROUGH WILL GIVE THE NORTHERN PORTION OF THE FRONT A PUSH EAST THOUGH...TAKING ON A MORE WEST-EAST ORIENTATION ACROSS NORTHERN IA/SOUTHERN WI BY LATE THIS AFTERNOON. SOME 2-D FRONTOGENETIC FORCING AROUND THE BOUNDARY...WITH WEAK BUT PERSISTENT 925-700 MB MOISTURE TRANSPORT INTO IT. THIS SHOULD BE ENOUGH TO CONTINUE/SPARK SHOWERS/STORMS IN THE VICINITY OF THE BOUNDARY TODAY DESPITE DECENT LOW LEVEL CAPPING INVERSION. TONIGHT...BOUNDARY WILL LIKELY CONTINUE TO WAVER JUST TO THE SOUTH...WITH AN INCREASING LOW LEVEL JET AND MOISTURE TRANSPORT INTO IT ALONG WITH AN UPPER LEVEL DISTURBANCE SPINNING OUT OF THE CENTRAL PLAINS. WOULD EXPECT ANOTHER AREA OF SHOWERS/STORMS TO BLOSSOM IN RESPONSE TO THIS FORCING. 1000-2500 J/KG OF MUCAPE AROUND AND NORTH OF THE BOUNDARY...WITH UP TO 40 KTS OF 0-6 KM SHEAR INDICATED TODAY. TONIGHT 500-1000 J/KG OF CAPE IN THE 1-6 KM LAYER WITH 30-40 KTS OF 0-6 KM SHEAR PERSISTING. CERTAINLY SOME STORM ORGANIZATION WILL BE POSSIBLE...WITH THE POTENTIAL FOR STRONG TO SEVERE STORMS. CONFIDENCE ISN/T HIGH IN WHEN/WHERE THE GREATER THREAT WILL BE...WITH CONVECTION IN THE WEST MOVING IN THIS MORNING...MODIFYING THE ATMOSPHERE AND ADDING AN ELEMENT OF UNCERTAINTY. SITUATION WILL HAVE TO BE MONITORED CLOSELY THROUGH THE DAY/NIGHT. ANOTHER UPPER LEVEL SHORTWAVE TROUGH WILL BEAR DOWN ON THE UPPER MISSISSIPPI RIVER VALLEY SATURDAY/SAT NIGHT...PUSHING ITS ASSOCIATED SFC COLD FRONT WELL AHEAD OF IT AND ACROSS THE REGION DURING THE DAY. THE 02.00Z GFS IS A BIT FASTER THAN THE NAM IN THIS STEAD. THIS SYSTEM GIVES THE LINGERING FRONT A FURTHER PUSH SOUTH...BUT WOULD ALSO BRING ANOTHER FOCUS FOR MORE SHOWERS/STORMS AS FRONTOGENETIC FORCING ALONG THIS COLD FRONT INTERACTS WITH WEAK MOISTURE TRANSPORT AND INSTABILITY. ENOUGH SHEAR TO FAVOR THE POTENTIAL FOR STORM ORGANIZATION AND STRONG/SEVERE DEVELOPMENT. THIS RISK MIGHT BE SHIFTED MORE EAST/SOUTH OF THE FORECAST AREA. WINDS WILL PICK UP ON SUNDAY POST THE SYSTEM WITH WRAP AROUND MOISTURE AROUND THE EXITING LOW LEADING TO MORE CLOUDS ACROSS THE NORTH. MORE SIGNIFICANTLY WITH THIS SYSTEM IS THAT A STRONG SLUG OF COLD AIR ADVECTION WILL LEAD TO TUMBLING TEMPS...DROPPING FROM 14 C AT 850 MB AT 00Z SUN TO 7 C BY 00Z MON. LOOK FOR A MUCH COOLER END TO THE EXTENDED HOLIDAY WEEKEND AS A RESULT WITH HIGHS IN THE 60S TO NEAR 70 AND LOWS FALLING OFF INTO THE 40S BY MONDAY MORNING. .LONG TERM...MONDAY THROUGH THURSDAY GFS AND ECMWF IN GOOD AGREEMENT WITH AMPLIFYING A FRIDGE OVER THE WEST COAST FOR NEXT WEEK...WHILE DEEPENING AN UPPER LEVEL TROUGH OVER THE EAST COAST. HIGH PRESSURE WOULD BE THE MAIN WEATHER INFLUENCE LOCALLY...RESULTING IN SEVERAL DRY DAYS WITH TEMPS NEAR THE SEASONABLE NORMALS. THERE DOES LIE THE POTENTIAL FOR SOME SHOWER/STORM CHANCES WED NIGHT AS A SHORTWAVE TROUGH SLIPS SOUTHEAST ACROSS THE GREAT LAKES. THE GFS HAS MORE ENERGY WEST WHICH LEADS TO A BETTER RAIN THREAT FOR THE UPPER MISSISSIPPI RIVER VALLEY. THE EC HINTS THAT IT COULD ALL STAY EAST. WILL LEAN ON THE CONSENSUS SOLUTION FOR THE DETAILS. && .AVIATION...TODAY THROUGH TONIGHT CURRENTLY WATCHING A COLD FRONT MOVING INTO FAR NORTHWEST WISCONSIN THROUGH WESTERN IA. RADAR MOSAIC SHOWING SHRA/TS ACTUALLY OCCURRING BEHIND THE FRONT CLOSER TO UPPER LEVEL SUPPORT. THE COLD FRONT IS EXPECTED TO SLIDE SOUTHEAST THROUGH THE AREA THIS MORNING WITH THAT POST-FRONTAL SHRA/TS ACTIVITY SPREADING INTO THE KRST/KLSE TAF SITES...REACHING KRST AROUND 10Z AND KLSE BY 13Z. VFR CONDITIONS EXPECTED WITHIN THIS SHRA/TS ACTIVITY THROUGH THIS MORNING AND EARLY AFTERNOON. MODEL SOUNDINGS/BUFKIT THEN INDICATE SOME LOWER MVFR STRATUS/STRATOCUMULUS LATER THIS AFTERNOON SPREADING ACROSS THE TAF SITES IN COLD AIR ADVECTION...LASTING INTO TONIGHT. FRONTAL BOUNDARY APPEARS TO STALL ACROSS SOUTHERN WI-CENTRAL IA OVERNIGHT FOR CONTINUED SCATTERED SHRA/ISOLD T ACTIVITY. THERE ARE INDICATIONS THAT VIS/CIG COULD EVEN FLIRT WITH IFR CONDITIONS AS THE VERY MOIST LOWER BOUNDARY LAYER COOLS OVERNIGHT/AFTER MIDNIGHT. WILL TAKE A CLOSER LOOK AT ALL THIS AND INCLUDE DETAILS WITH THE 02.12Z TAF ISSUANCE. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && SHORT/LONG TERM... RIECK AVIATION.......... DAS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE LA CROSSE WI 415 AM CDT FRI SEP 2 2011 IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-032>034- 041>044-053>055-061-031000- ADAMS-ALLAMAKEE-BUFFALO-CHICKASAW-CLARK-CLAYTON-CRAWFORD-DODGE- FAYETTE-FILLMORE-FLOYD-GRANT-HOUSTON-HOWARD-JACKSON-JUNEAU-LA CROSSE- MITCHELL-MONROE-MOWER-OLMSTED-RICHLAND-TAYLOR-TREMPEALEAU-VERNON- WABASHA-WINNESHIEK-WINONA- 415 AM CDT FRI SEP 2 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PARTS OF NORTHEAST IOWA... SOUTHEAST MINNESOTA...AND SOUTHWEST INTO CENTRAL WISCONSIN. .DAY ONE...TODAY AND TONIGHT THUNDERSTORMS WILL MOVE ACROSS THE AREA THIS MORNING...SOME OF WHICH COULD BE SEVERE PRODUCING DAMAGING WINDS AND LARGE HAIL. MORE THUNDERSTORMS WILL BE POSSIBLE LATER THIS AFTERNOON AND TONIGHT. THERE WOULD BE THE THREAT FOR STRONG...TO POSSIBLY SEVERE THUNDERSTORMS WITH THIS ACTIVITY. LARGE HAIL...DAMAGING WINDS...AND HEAVY RAIN WILL BE THE MAIN THREATS. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY A COLD FRONT WILL PROVIDE THE FOCUS FOR MORE THUNDERSTORMS ON SATURDAY. A FEW OF THESE STORMS COULD BECOME STRONG TO SEVERE...WITH THE HIGHER RISK OVER SOUTHERN WISCONSIN AND EASTERN IOWA. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED THIS MORNING. FURTHER ACTIVATION COULD BE REQUESTED FOR LATER TODAY AND TONIGHT... AND POSSIBLY SATURDAY. .EMERGENCY MANAGEMENT COORDINATION... NO WEBINAR IS SCHEDULED. RIECK
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE LA CROSSE WI 518 AM CDT FRI SEP 2 2011 IAZ008-009-018-019-MNZ079-086-087-094-095-021230- CHICKASAW-DODGE-FILLMORE-FLOYD-HOWARD-MITCHELL-MOWER-OLMSTED-WABASHA- 518 AM CDT FRI SEP 2 2011 ...STRONG STORMS MOVING IN... STRONG THUNDERSTORMS WERE MARCHING IN FROM THE WEST...PRODUCING HEAVY RAIN...WIND GUSTS TO 40 MPH...AND POSSIBLY SMALL HAIL. THE STORMS COULD INCREASE IN STRENGTH AND BECOME SEVERE OVER THE NEXT COUPLE HOURS...WITH A DAMAGING WIND AND LARGE HAIL THREAT. HEAVY DOWNPOURS COULD ALSO LEAD TO PONDING OF WATER ON SOME ROADWAYS AND LOCALIZED URBAN FLOODING. MORNING COMMUTERS AND THOSE GETTING A HEAD START ON THE LABOR DAY WEEKEND SHOULD BE PREPARED FOR STORMY TRAVEL EARLY THIS MORNING. RIECK
The La Crosse radar (KARX), 145 km away, was scanning. The volume nearest the first event began at 10:53 UTC.
8 thunderstorm wind. Local standard time, as filed.
Trees and power lines were knocked down in Lyle and some penny sized hail also fell. One of the trees fell on a garage causing some minor damage.
Large tree branches were blown down in Spring Valley along with a few trees over County Road 1.
An estimated a wind gust of 60 miles per hour blew down several branches two miles northeast of Newburg.
An estimated 60 miles per hour wind gust occurred four miles southwest of Winona.
Trees were blown down along State Highway 16.
An estimated a 60 mile per hour wind gust occurred near Pickwick.
Trees were blown down southwest of Reno including an 18 inch diameter cottonwood.
Numerous trees and power lines were blown down near Brownsville.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Minnesota in 2011Every state in 2011This day in weather historyWarnings in Minnesota, September 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: 341597, 341596, 341590, 341592, 341589, 341593, 347377, 341594.