Showers and thunderstorms developed across southeast Minnesota on the afternoon of May 4th as a cold front advanced east across Minnesota and Iowa. Although these thunderstorms were not very intense, they did produce strong winds in some locations as they moved east.
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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.
Showers and thunderstorms developed across southeast Minnesota on the afternoon of May 4th as a cold front advanced east across Minnesota and Iowa. Although these thunderstorms were not very intense, they did produce strong winds in some locations as they moved east.
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 May 4, 2:00 PM CST, 1 hour 54 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 300 PM CDT TUE MAY 4 2010 .SHORT TERM...THROUGH THURSDAY NIGHT MAIN CONCERNS ARE WITH THE RAIN CHANCES TONIGHT...WEDNESDAY AND THURSDAY INTO THURSDAY NIGHT ALONG WITH THE WINDS FOR WEDNESDAY. SURFACE ANALYSIS THIS AFTERNOON IS RATHER COMPLEX WITH ONE AREA OF LOW PRESSURE OVER NORTHEAST MONTANA...A SECOND OVER NORTHWEST MINNESOTA AND YET A THIRD IN SOUTH CENTRAL MINNESOTA. A COLD FRONT CONNECTS ALL THREE AND EXTENDS SOUTHWEST FROM THE THIRD LOW INTO SOUTH CENTRAL NEBRASKA. A WARM FRONT EXTENDS SOUTHEAST FROM THE TWIN CITIES AREA TOWARD CHICAGO. SATELLITE SHOWING A LINE OF CLOUDS ALONG THE COLD FRONT FROM SOUTHERN MINNESOTA INTO NEBRASKA BUT NO RADAR RETURNS OF SIGNIFICANCE YET. AS THE COLD FRONT CONTINUES TO WORK EAST INTO THE EVENING...THE 04.12Z NAM SHOWS THE LOW LEVEL MOISTURE TRANSPORT INCREASES AHEAD OF THE FRONT ACROSS THE AREA. THE LOW LEVEL FRONTOGENESIS IN THE 1000-850 MB LAYER BECOMES STRONG AS DOES THE FN VECTOR CONVERGENCE. THE UP GLIDE ON THE 300K ISENTROPIC SURFACE IS EXPECTED TO BE 3 TO 5 UBAR/S...SO THERE APPEARS TO BE ENOUGH FORCING TO GET SOME CONVECTION GOING. THE CONCERN IS WHETHER THIS WILL BE ENOUGH TO OVERCOME SURFACE DEW POINTS IN THE 40S. WITH THE CLOUD FIELD SLOWLY INCREASING AHEAD OF THE FRONT BELIEVE THERE SHOULD AT LEAST BE SOME HIGH BASED ACTIVITY AND WENT WITH 50 TO 60 RAIN CHANCES AS THE FRONT COMES THROUGH. THE RAIN CHANCES FOR WEDNESDAY LOOK TO BE CONFINED TO THE FAR NORTHERN SECTIONS OF THE FORECAST AREA. BOTH THE NAM AND GFS BRING A RATHER STRONG SHORT WAVE TROUGH ACROSS THE REGION WHICH RESULTS IN UP TO 16 PVU/S OF VORTICITY ADVECTION IN THE 500-300 MB LAYER. SOME WRAP AROUND WARM AIR ADVECTION WILL PRODUCE ABOUT 2 UBAR/S OF UP GLIDE ON THE 295K SURFACE. SOME INSTABILITY WILL BE PRESENT ACROSS THE NORTH AS WELL WITH THE NAM BUFKIT SOUNDING FOR KRCX SHOWING UP TO 8 C/KM UP THROUGH 650 MB. OPTED TO INCREASE THE CLOUD COVER AND ADD A 20 RAIN CHANCE ACROSS THE NORTH. THE OTHER CONCERN FOR WEDNESDAY IS WITH THE WINDS. AS THE MAIN SURFACE LOW TRANSITIONS EAST INTO THE GREAT LAKES...A TIGHT PRESSURE GRADIENT WILL DEVELOP. THIS COUPLED WITH THE STRONG LOW LEVEL LAPSE RATES SHOULD PRODUCE A WINDY DAY WITH SUSTAINED SPEEDS OF 25 MPH AND GUSTS OF 35 TO 40 MPH. WITH THE LACK OF GOOD SUBSIDENCE DO NOT BELIEVE SPEEDS WILL REACH ADVISORY CRITERIA. THE NEXT SYSTEM WILL QUICKLY ADVANCE TOWARD THE AREA FOR THURSDAY AND THURSDAY NIGHT. A STRONG UPPER LEVEL LOW WILL ADVANCE ON TO THE HIGH PLAINS THURSDAY NIGHT WITH THE MAIN SURFACE LOW TRACKING ACROSS MISSOURI INTO ILLINOIS WITH A TROUGH OF LOW PRESSURE EXTENDING BACK TO THE NORTHWEST TOWARD THE UPPER LEVEL LOW. STRONG WARM AIR ADVECTION WILL OCCUR AHEAD OF THE SYSTEM YIELDING UP TO 10 UBAR/S OF UP GLIDE ON THE 295K SURFACE. SPECIFIC HUMIDITIES ON THIS LEVEL SHOULD INCREASE TO 6-8 G/KM THURSDAY NIGHT WITH THE NOSE OF THE MOISTURE TRANSPORT RIGHT INTO THE FORECAST AREA. PUSHED THE ARRIVAL OF ANY RAIN BACK INTO THURSDAY AFTERNOON AND THEN WITH THE BEST FORCING EXPECTED THURSDAY NIGHT RAISED THE POPS TO 50 ACROSS THE NORTH TO 70 IN THE SOUTH. ALSO ADDED SOME THUNDER ACROSS THE SOUTH FOR THURSDAY NIGHT WITH THE GFS SHOWING AROUND 250 J/KG ABOVE 2 KM. .LONG TERM...FRIDAY THROUGH TUESDAY THE LATEST SET UP MEDIUM RANGE MODELS ARE IN VERY GOOD AGREEMENT TODAY. THE UPPER LEVEL TROUGH OVER THE UPPER MIDWEST EARLY IN THE PERIOD WILL EXIT OUT TO THE NORTHEAST FOLLOWED BY A PERIOD OF RIDGING THROUGH EARLY NEXT WEEK. THIS RIDGE THEN LOOKS TO SHIFT EAST AS THE NEXT SYSTEM IN THE ACTIVE FLOW SHIFTS OVER THE UPPER MIDWEST. SOME DIFFERENCES BETWEEN THE 04.06Z GFS AND THE 04.00Z ECMWF ON HOW LONG ANY LINGERING PRECIPITATION ON THE BACK SIDE OF THE DEPARTING SURFACE LOW WILL REMAIN OVER THE AREA. THE GFS WOULD SUGGEST THE PRECIPITATION WOULD END FRIDAY NIGHT WHILE THE ECMWF HOLDS ON TO SOME THROUGH SATURDAY. FOR NOW...HAVE HELD ON TO SOME LOW PRECIPITATION CHANCES THROUGH SATURDAY TO HONOR THE ECMWF SOLUTION. THIS LEADS TO A PRECIPITATION TYPE CONCERN FOR FRIDAY NIGHT WITH THE ECMWF SUGGESTING BOTH 850 MB AND 925 MB TEMPERATURES DROPPING BELOW ZERO OVER THE NORTHEAST SECTIONS OF THE FORECAST AREA FOR A POSSIBLE RAIN/SNOW MIX. BROUGHT SOME RAIN CHANCES BACK TO THE AREA STARTING MONDAY AHEAD OF THE NEXT SYSTEM AND MAINTAINED THESE THROUGH TUESDAY AS THE SURFACE LOW TRACKS NORTHEAST ACROSS THE IMMEDIATE REGION. LITTLE TO NO CAPE IS FORECAST TO BE PRESENT BY THE ECMWF SO DID NOT INCLUDE ANY THUNDER. && .AVIATION... A STORMY LATE AFTERNOON THROUGH MID EVENING IS EXPECTED AS A COLD FRONT WORKS EST ACROSS THE AREA. FELT CONFIDENT ENOUGH TO INCLUDE TEMPO THUNDERSTORM GROUPS AT BOTH TAF SITES FROM LATE AFTERNOON INTO THE EARLY EVENING HOURS. A FEW OF THESE STORMS MAY BE STRONG WITH SOME HAIL AND WIND GUSTS AROUND 40KT. VFR CONDITIONS EXPECTED OVERALL...BUT MAY BE REDUCED INTO BRIEF MVFR WITH HEAVIER RAIN REDUCING THE VISIBILITY. THE COLD FRONT AND SHRA/TS ACTIVITY EXPECTED TO EXIT EAST OF THE AREA BY LATE EVENING...BUT WINDS MAY REMAIN BREEZY THROUGH MIDNIGHT OR SO BEFORE DECOUPLING. VFR CONDITIONS WILL THEN PREVAIL THE REST OF TONIGHT THROUGH WEDNESDAY MORNING. WEST WINDS ARE EXPECTED TO BECOME QUITE BREEZY BY MID/LATE WEDNESDAY MORNING AS LOW PRESSURE PASSES NORTH OF THE AREA. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && SHORT/LONG TERM...04 AVIATION...DAS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE LA CROSSE WI 1107 AM CDT TUE MAY 4 2010 IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-032>034- 041>044-053>055-061-051000- 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- 1107 AM CDT TUE MAY 4 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND SOUTHWEST INTO CENTRAL WISCONSIN. .DAY ONE...TODAY AND TONIGHT A WARM FRONT WILL MOVE NORTHEAST INTO THE REGION TODAY...WHILE A COLD FRONT SLIDES IN FROM THE WEST LATE THIS AFTERNOON INTO THIS EVENING. SHOWERS AND THUNDERSTORMS WILL FIRE AROUND BOTH BOUNDARIES...MOSTLY FROM LATE AFTERNOON THROUGH TONIGHT. INSTABILITY AND FAVORABLE WIND PROFILES SUPPORT STRONG TO SEVERE THUNDERSTORMS. ALTHOUGH AN ISOLATED TORNADO IS POSSIBLE...LARGE HAIL AND DAMAGING WINDS LOOK TO BE THE MAIN THREAT ALONG AND NORTH OF INTERSTATE 94 IN THE VICINITY OF THE WARM FRONT. SOUTH OF THIS...THUNDERSTORMS WITH SCATTERED DAMAGING WIND GUSTS ALONG WITH SOME LARGE HAIL WILL BE THE MAIN SEVERE THREATS ALONG THE COLD FRONT. THE MAIN SEVERE THREAT TIME LOOKS TO BE BETWEEN 4 AND 10 PM. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED BETWEEN 4 AND 10 PM TONIGHT. .EMERGENCY MANAGEMENT COORDINATION... NO CALL IS SCHEDULED. DAS/RIECK
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE LA CROSSE WI 421 PM CDT TUE MAY 4 2010 WIZ029-033-034-042215- CLARK-JACKSON-TREMPEALEAU- 421 PM CDT TUE MAY 4 2010 ...GUSTY WINDS EXPECTED WITH A LINE OF SHOWERS... AT 416 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED SHOWERS ALONG A LINE EXTENDING FROM 33 MILES NORTHWEST OF NEILLSVILLE TO 20 MILES SOUTHWEST OF BLACK RIVER FALLS...MOVING EAST AT 45 MPH. WINDS UP TO 50 MPH ARE POSSIBLE WITH THESE SHOWERS. WHEN THE SHOWERS PASSED THROUGH THE WINONA MUNICIPAL AIRPORT...WINDS GUSTED TO 47 MPH. * THE SHOWERS WILL BE NEAR... PRICE BY 425 PM CDT... HUMBIRD BY 435 PM CDT... BLACK RIVER FALLS BY 440 PM CDT... HATFIELD BY 445 PM CDT... NEILLSVILLE AND MILLSTON BY 455 PM CDT... SHORTVILLE AND LOYAL BY 500 PM CDT... GUSTY WINDS MAY CAUSE SMALL BRANCHES TO BE BLOWN DOWN...AND LOOSE OBJECTS TO BLOW AROUND. SEEK SHELTER IN A STURDY STRUCTURE UNTIL THESE SHOWERS HAVE PASSED. AJ
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE LA CROSSE WI 434 PM CDT TUE MAY 4 2010 IAZ008>010-018-019-MNZ079-086>088-094>096-WIZ017-029-032>034-041- 042-042300- MITCHELL-HOWARD-WINNESHIEK-FLOYD-CHICKASAW-WABASHA-DODGE-OLMSTED- WINONA-MOWER-FILLMORE-HOUSTON-TAYLOR-CLARK-BUFFALO-TREMPEALEAU- JACKSON-LA CROSSE-MONROE- INCLUDING THE CITIES OF...DECORAH...CHARLES CITY...ROCHESTER... WINONA...AUSTIN...MEDFORD...NEILLSVILLE...BLACK RIVER FALLS... LA CROSSE...SPARTA/TOMAH 434 PM CDT TUE MAY 4 2010 ...SHOWERS PRODUCING STRONG GUSTY WINDS... LOOK FOR SHOWERS TO CONTINUE TO DEVELOP OVER SOUTHEAST MINNESOTA... NORTHEAST IOWA AND WESTERN WISCONSIN THROUGH 6 PM. THESE SHOWERS HAVE HAD A HISTORY OF PRODUCING STRONG WIND GUSTS...WITH REPORTS OF 47 MPH AT THE WINONA MUNICIPAL AIRPORT AND 48 MPH IN MASON CITY. IF A SHOWER CROSSES...BE PREPARED FOR WIND GUSTS OF UP TO 50 MPH. THESE WIND GUSTS MAY CAUSE LOOSE OBJECTS TO BLOW AROUND...BRANCHES TO BE BLOWN DOWN...AND MAKE TRAVEL DIFFICULT...ESPECIALLY FOR HIGH PROFILE VEHICLES. AJ
The Minneapolis radar (KMPX), 109 km away, was scanning. The volume nearest the first event began at 21:52 UTC.
3 thunderstorm wind. Local standard time, as filed.
The automated weather observing equipment at the Dodge Center airport reported a wind gust of 67 mph as a weak thunderstorm passed by. At this time, it also indicated a sustained wind speed of 43 mph.
Strong winds were observed as a weak thunderstorm passed by, which caused a large tree of approximately 2 feet in diameter to snap several feet from the base.
The automated weather observing equipment at the Rochester International Airport reported a wind gust of 59 mph as a weak thunderstorm passed by the site.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Minnesota in 2010Every state in 2010This day in weather historyWarnings in Minnesota, May 2010
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: 222577, 222579, 222578.