Thunderstorms that developed over South Dakota during the early morning hours of May 26th held together past sunrise and intensified over southeast Minnesota during the late morning. These storms dumped some hail and heavy rain across portions of southeast Minnesota with quarter sized hail reported near Claremont (Dodge County).
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.
Thunderstorms that developed over South Dakota during the early morning hours of May 26th held together past sunrise and intensified over southeast Minnesota during the late morning. These storms dumped some hail and heavy rain across portions of southeast Minnesota with quarter sized hail reported near Claremont (Dodge County). A wind gust approaching 70 mph hit the Rochester Airport (Olmsted County) but did not produce any 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 La Crosse, WI wrote its last area forecast discussion before the first event at May 26, 5:15 AM CST, 5 hours 30 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 615 AM CDT SAT MAY 26 2012 .SHORT TERM...TODAY THROUGH MONDAY NIGHT 337 AM CDT SAT MAY 26 2012 MAIN FORECAST CONCERN IS ON CONVECTIVE EVOLUTION FOR TODAY AND TONIGHT. CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED DEEP TROUGHING ALONG THE WEST COAST OF THE U.S. AND STRONG RIDGING BUILDING UP FROM THE LOWER INTO MIDDLE MISSISSIPPI RIVER VALLEY. IN-BETWEEN THE TWO FEATURES...A SUBTROPICAL STREAM OF MOISTURE WITH EMBEDDED WEAK SHORTWAVES IS EVIDENT FROM MEXICO UP INTO IOWA. UNDERNEATH THIS SAME SUBTROPICAL STREAM AREA...A SOUTHWEST 40-50 KT JET EXISTS AT 850MB PER PROFILER DATA...WHICH IS RAPIDLY SENDING MOISTURE AND HEAT NORTHWARD. 00Z RAOBS SHOWED 850MB TEMPS OF 20C OR MORE FROM NEAR TOPEKA KS SOUTHWARD TO THE GULF COAST. COMPARE THESE TO 8C AT MPX AND 15C AT DVN. MOISTURE-WISE... SURFACE DEWPOINTS CURRENTLY RANGE FROM 65 TO 70F NEAR TOPEKA KS SOUTHWARD. THE GRADIENT OF THE 850MB MOISTURE TRANSPORT EXISTS FROM THE NEBRASKA/SOUTH DAKOTA BORDER EASTWARD INTO THE SOUTHERN HALF OF THE FORECAST AREA. CONVERGENCE ALONG THIS GRADIENT HAS BEEN PRODUCING NUMEROUS SHOWERS AND EMBEDDED THUNDERSTORMS. THESE ARE WELL NORTH OF THE MAIN SURFACE WARM FRONT...WHICH EXISTS JUST NORTH OF I-70 IN KANSAS AND MISSOURI. TODAY AND TONIGHT...UPPER TROUGHING ALONG THE WEST COAST IS PROGGED TO SHIFT EAST INTO THE ROCKIES. PERSISTENT WARM ADVECTION DOWNSTREAM WILL HELP TO BUILD THE RIDGING OVER THE MID-MISSISSIPPI RIVER VALLEY NORTHWARD...HELPING ALSO TO BRING THE WARM FRONT NEAR I-70 NORTH. MAIN QUESTION THROUGH TONIGHT IS THE AMOUNT OF CONVECTION WITH THE FRONT. THE CURRENT STREAM OF 850MB MOISTURE TRANSPORT AND GRADIENT IS FORECAST BY ALL MODELS TO WEAKEN SOME THIS MORNING AND SHIFT NORTH ACROSS THE AREA. THE WEAKENING IS LIKELY CAUSED BY THE NORMAL DIURNAL DIMINISHING OF LOW LEVEL JETS. THEREFORE...THINKING THAT THE CURRENT ACTIVITY WILL SLOWLY SHIFT NORTH AND WEAKEN THROUGH THE MORNING. ALSO...AS THE DAY WEARS ON...THERE APPEARS TO BE A SHIFT WESTWARD WITH THE MAIN FOCUS OF 850MB MOISTURE TRANSPORT TOWARDS THE DAKOTAS AND CENTRAL/NORTHERN MINNESOTA. ANOTHER ISSUE OF CONCERN IS THE SUBTROPICAL STREAM AND WEAK EMBEDDED SHORTWAVES WITHIN IT. THIS STREAM SHOULD SHIFT NORTH OVER THE FORECAST AREA DURING THE AFTERNOON. WITH THE SURFACE WARM FRONT LIFTING NORTH INTO NORTHERN IOWA BY 00Z...THIS SITUATION COULD RESULT IN CONVECTIVE DEVELOPMENT. HOWEVER...ANY DEVELOPMENT LOOKS LIKE IT WILL HAVE TO BE ELEVATED BECAUSE SURFACE-BASED PARCELS ARE SUBSTANTIALLY CAPPED (MLCIN PROGGED AT 200 J/KG OR MORE). CONFIDENCE ON THE SHORTWAVES PRODUCING CONVECTION ABOVE THE CAP IS LOW. THERE IS INSTABILITY ABOVE THE CAP...GENERALLY LESS THAN 700 J/KG. SO CANNOT COMPLETELY RULE OUT CONVECTION...BUT WOULD NOT BE SURPRISED EITHER IF IT ENDS UP DRY. SHOULD CONVECTION FIRE ABOVE THE CAP...THE 2-8 KM SHEAR (ESTIMATED EFFECTIVE BULK SHEAR LAYER) IS LESS THAN 30 KT AT BEST. WITH WARM CLOUD DEPTHS BETWEEN 3.5-4 KM...THEREFORE...WOULD ONLY EXPECT GUSTY WINDS AND BRIEF HEAVY RAIN TO BE THE MAIN ISSUES. OVERALL FOR PRECIPITATION CHANCES...KEPT THEM HIGH EARLY THIS MORNING...THEN GRADUAL LOWERING THROUGH THE DAY. FOR TONIGHT...THE 850MB MOISTURE TRANSPORT INCREASES AGAIN...THOUGH THE GRADIENT LOOKS MOSTLY TO THE NORTH FROM ALL MODELS. WILL LEAVE SOME CHANCES...HIGHEST NORTH OF I-90 AS NOTED BY THE 26.00Z NAM/GFS...BUT IT IS ENTIRELY POSSIBLE ANY ACTIVITY ENDS UP NORTH OF OUR AREA TONIGHT AS SUGGESTED BY THE 26.00Z GEM. BELIEVE THE 26.00Z ECMWF IS TOO FAR SOUTH AS IT SUGGESTS QPF PRODUCED ON THE NOSE OF 925MB MOISTURE TRANSPORT...BUT ECMWF SOUNDINGS SUGGEST TOO MUCH CAPPING LIFTED FROM 925 OR 850MB WHERE QPF EXISTS. FOR TEMPERATURES...GENERALLY STAYED CLOSE TO A BLEND OF GUIDANCE. THEY ARE VERY TRICKY TODAY DUE TO CLOUDS...BUT AT THE SAME TIME WARM ADVECTION IN PLACE. HIGH TEMPERATURE IS LIKELY TO OCCUR AT 00Z. SUNDAY...HOT DAY STILL LOOKS ON TAP WITH THE WARM FRONT MOSTLY NORTH OF THE AREA. MAINTAINED A LOW...20 PERCENT...CHANCE OF STORMS IN THE MORNING OVER TAYLOR COUNTY. THIS IS WHERE THE NOSE OF THE 850MB MOISTURE TRANSPORT STILL EXISTS. OTHERWISE...MOSTLY SUNNY CONDITIONS LOOK TO BE THE RULE. 850MB TEMPS OF 20C OR MORE PLUS A BREEZY SOUTHWEST WIND ALL SUPPORT HIGHS CLIMBING INTO THE LOW 90S. SOME LOCATIONS TOO COULD HIT THE MID 90S SINCE DEEP MIXING IS SUGGESTED ON SOUNDINGS. PREVIOUS FORECAST HIGHS SEEM REASONABLE. DEWPOINTS SHOULD FALL THROUGH THE DAY WITH THE MIXING...BUT STAYING UP SOMEWHAT DUE TO RECENT RAIN. SUNDAY NIGHT THROUGH MONDAY NIGHT...TROUGHING OVER THE ROCKIES IS PROGGED TO LIFT NORTHEAST DURING THIS PERIOD...WITH THE CORE OF IT REACHING NORTHWEST ONTARIO AT 12Z TUE. HEIGHT FALLS WITH THIS TROUGH...AND THE ASSOCIATED COLD FRONT...LOOK TO COME ACROSS THE FORECAST AREA LATE SUNDAY NIGHT INTO MONDAY. GOOD CONSENSUS EXISTS THAT A SQUALL LINE WILL FORM ALONG THE COLD FRONT IN THE EASTERN DAKOTAS/WESTERN MINNESOTA SUNDAY EVENING. THIS IS IN AN AREA OF MODERATE INSTABILITY AND 40 KT OF 0-6 KM SHEAR. THE SQUALL LINE SHOULD REACH SOME OF NORTHEAST IOWA...SOUTHEAST MINNESOTA AND NORTHWEST WISCONSIN AFTER MIDNIGHT...WITH ITS SPEED BEING INCREASED SOMEWHAT BY COLD POOL DEVELOPMENT. WHETHER IT IS SEVERE OR NOT BY THE TIME IT GETS TO OUR FORECAST AREA IS A BIG QUESTION...SINCE THE INSTABILITY DECREASES THROUGH THE NIGHT. CERTAINLY THE SHEAR IS PLENTIFUL...BOTH 0-3KM AND 0-6KM...SO IT IS JUST A MATTER OF INSTABILITY. GENERAL CONSENSUS IS THAT THE SQUALL LINE MAY HAVE COMPLETELY DISSIPATED OR BROKEN UP INTO JUST ISOLATED-SCATTERED CONVECTION MONDAY MORNING DUE TO LOSS OF INSTABILITY. AS SUCH...REDUCED CHANCES OF PRECIPITATION FOR 12-18Z MONDAY. AS THE FRONT MOVES INTO THE EASTERN PORTIONS OF THE FORECAST AREA AND INSTABILITY BUILDS...CONVECTION MAY RE-FIRE ON THE FRONT. UNDERSCORE MAY...SEEING THE NEW 26.00Z ECMWF WHICH IS MOSTLY DRY. AGAIN... PLENTY OF SHEAR EXISTS SO POTENTIAL IS THERE FOR SEVERE WEATHER. ANOTHER PROBLEM WITH SEVERE POTENTIAL ON MONDAY IS THAT THE FRONT COULD BE EAST OF THE AREA BY THE TIME STORMS IF THEY FORM TURN SEVERE. WE WILL HAVE TO WAIT AND SEE. DRY SLOT COMES IN BEHIND THE FRONT TO END PRECIPITATION. IT NOW APPEARS ANY PRECIPITATION SHOULD BE EAST OF THE AREA MONDAY NIGHT...THEREFORE...DRIED OUT THE FORECAST MONDAY NIGHT. WARM NIGHT LIKELY ON TAP SUNDAY NIGHT AHEAD OF THE FRONT WITH LOWS NEAR 70. WITH POTENTIAL FOR MORE SUN ON MONDAY AND 850MB TEMPS ONLY DROPPING TO 10-14C AT MOST...HIGHS SHOULD EASILY CLIMB WELL INTO THE 70S AND EVEN LOW TO MID 80S OVER THE EASTERN AREAS AHEAD OF THE FRONT. COOLER NIGHT UNDER MOSTLY CLEAR SKIES ANTICIPATED FOR MONDAY NIGHT. .LONG TERM...TUESDAY THROUGH FRIDAY NIGHT 337 AM CDT SAT MAY 26 2012 AFTER A FAIRLY ACTIVE SHORT TERM PERIOD...THE LONG TERM LOOKS PRETTY QUIET. VERY GOOD MODEL AGREEMENT EXISTS OF SOME FORM OF TROUGHING OVER THE WESTERN GREAT LAKES REGION THROUGHOUT THE REST OF NEXT WEEK. THIS SET UP ALLOWS FOR MUCH OF THE AREA TO BE DOMINATED BY SURFACE HIGH PRESSURE AND A DRY AIR FLOW. MOST OF THE SHORTWAVES SLIDING THROUGH THE NORTHWEST FLOW ALOFT HEAD SOUTHWEST OF THE AREA...A PROBLEM NOTED YESTERDAY. ONE CONCERN TO WATCH OUT FOR IS THE COOLER TEMPERATURES ALOFT AND IF ANY DIURNAL PRECIPITATION CAN FORM. THE 26.00Z ECMWF HINTS AT THIS ON WEDNESDAY...THOUGH ITS PREVIOUS RUN DID NOT. FOR NOW...HAVE FOLLOWED THE CONSENSUS APPROACH WHICH BASICALLY RESULTS IN AN ENTIRELY DRY FORECAST...EXCLUDING A LITTLE LIGHT SHOWER CHANCE ON TUESDAY OVER NORTH CENTRAL WISCONSIN. TEMPERATURES ARE LIKELY TO BE BELOW NORMAL THROUGHOUT DUE TO THE TROUGHING. SOMETHING AGAIN TO WATCH OUT FOR IS ANY CLEAR NIGHTS AND AT SOME OF THE TYPICAL COLD SPOTS FOR POSSIBLE FROST FORMATION. RIGHT NOW...TUESDAY NIGHT AND WEDNESDAY NIGHT WOULD BE THE NIGHTS TO KEEP A CLOSE EYE ON. && .AVIATION...TODAY AND TONIGHT 614 AM CDT SAT MAY 26 2012 SHOWERS AND ISOLATED THUNDERSTORMS WILL MOVE EAST OF THE TAF SITES BY 15Z THIS MORNING. VFR CONDITIONS ARE EXPECTED THROUGH THIS AFTERNOON WITH CLOUD BASES IN THE 5 TO 10 KFT RANGE. A WARM FRONT WILL LIFT THROUGH THE AREA THIS AFTERNOON FROM SOUTHERN IOWA...POSSIBLY PRODUCING A FEW SHOWERS AND STORMS. CONFIDENCE LOW ON SHOWERS OR THUNDERSTORMS OCCURRING THIS AFTERNOON AS THE FRONT MOVES IN WITH FORECAST SOUNDINGS SHOWING STRONG CONVECTIVE INHIBITION MOVING OVER THE AREA WITH MUCH WARMER AIR MOVING IN AROUND THE 800 MB LAYER...EFFECTIVELY CAPPING THE ATMOSPHERE FOR THUNDERSTORM DEVELOPMENT. WILL HAVE TO CLOSELY MONITOR THE CAPPING THIS AFTERNOON. IF THE CAP IS WEAKER THAN CURRENT GUIDANCE SUGGESTS...THUNDERSTORMS WILL BE A POSSIBILITY. LOOK FOR SOUTHEAST WINDS TO INCREASE INTO THE 12 TO 16 KT RANGE TODAY WITH GUSTS TO AROUND 25 KTS POSSIBLE. VFR CONDITIONS ARE EXPECTED THIS EVENING THROUGH THE OVERNIGHT HOURS AS THE WARM FRONT LIFTS INTO NORTHERN WISCONSIN/MINNESOTA. FORECAST MODELS ARE HINTING AT LOW LEVEL MOISTURE EDGING INTO THE TAF SITES LATE THIS EVENING INTO THE OVERNIGHT HOURS...POSSIBLY PRODUCING SOME MVFR/IFR CEILINGS. CURRENT THINKING IS THAT THERE WILL BE ENOUGH MIXING/DRYING BEHIND THE WARM FRONT TO INHIBIT LOW CLOUD DEVELOPMENT BUT WILL HAVE TO KEEP A CLOSE WATCH ON THE NEXT SET OF FORECAST MODEL RUNS. && .ARX WATCHES/WARNINGS/ADVISORIES... 337 AM CDT SAT MAY 26 2012 WI...NONE. MN...NONE. IA...NONE. && SHORT TERM...AJ LONG TERM...AJ AVIATION...WETENKAMP
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE LA CROSSE WI 906 AM CDT SAT MAY 26 2012 IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-032>034- 041>044-053>055-061-271100- 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- 906 AM CDT SAT MAY 26 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PARTS OF SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND SOUTHWEST INTO CENTRAL WISCONSIN. .DAY ONE...TODAY AND TONIGHT THUNDERSTORMS ARE POSSIBLE THROUGH TONIGHT. THE GREATEST CHANCES FOR THUNDERSTORMS ARE OVER SOUTHEAST MINNESOTA LATE THIS MORNING INTO THE EARLY AFTERNOON AND OVER WESTERN WISCONSIN FOR THE EARLY AND MID AFTERNOON HOURS. ADDITIONAL THUNDERSTORMS WILL BE POSSIBLE TONIGHT ALONG AND NORTH OF INTERSTATE 94. GUSTY WINDS...HEAVY RAIN AND LIGHTNING WILL BE THE MAIN HAZARDS WITH ANY STORMS THAT OCCUR. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY ADDITIONAL THUNDERSTORMS ARE POSSIBLE SUNDAY NIGHT INTO MONDAY. THERE IS THE POTENTIAL FOR SEVERE WEATHER WITH THESE STORMS...MAINLY WEST OF THE MISSISSIPPI RIVER SUNDAY NIGHT AND EAST OF THE MISSISSIPPI RIVER MONDAY AFTERNOON. HOWEVER...IT IS UNCERTAIN AT THIS TIME WHAT TYPES OF SEVERE WEATHER COULD OCCUR. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION SHOULD NOT BE NEEDED THROUGH TONIGHT. HOWEVER... ANY WIND OR RAINFALL REPORTS WOULD BE APPRECIATED. .EMERGENCY MANAGEMENT COORDINATION... NO WEBINAR IS SCHEDULED. 04
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE LA CROSSE WI 642 AM CDT SAT MAY 26 2012 IAZ011-030-WIZ054-055-061-261245- ALLAMAKEE-CLAYTON-CRAWFORD-GRANT-RICHLAND- 642 AM CDT SAT MAY 26 2012 AT 637 AM...DOPPLER RADAR INDICATED STRONG THUNDERSTORMS FROM CASTLE ROCK TO 10 MILES SOUTH OF WOOD...MOVING EAST AT 40 MPH. BRIEF HEAVY RAIN WILL ACCOMPANY THESE STRONG THUNDERSTORMS. LOCATIONS THAT MAY BE AFFECTED INCLUDE... CASSVILLE...LANCASTER...PLATTEVILLE...DICKEYVILLE AND CUBA CITY. HEAVY RAIN COULD LEAD TO MINOR FLOODING OR A SHORT PERIOD OF STANDING WATER. STAY CLEAR OF DRAINAGE AREAS AND AVOID AREAS OF HIGH WATER IF THEY DEVELOP. WETENKAMP
The Minneapolis radar (KMPX), 103 km away, was scanning. The volume nearest the first event began at 16:46 UTC.
3 hail, 1 thunderstorm wind, 1 heavy rain. Local standard time, as filed.
In addition to the quarter sized hail, 1.73 inches of rain fell in about a half hour ending at 11:15 a.m. south of Claremont.
The automated weather observing equipment at the Rochester International airport measured a wind gust of 69 mph.
Over two inches of rain fell in about a half hours time near Eyota.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Minnesota in 2012Every state in 2012This day in weather historyWarnings in Minnesota, 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: 379733, 379737, 379742, 379741, 379743.