Thunderstorms that developed across southern Minnesota, moved northward during the evening of Saturday May 26th, and produced torrential rainfall, and damaging winds in portions of the Mille Lacs Lake area.
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.
Thunderstorms that developed across southern Minnesota, moved northward during the evening of Saturday May 26th, and produced torrential rainfall, and damaging winds in portions of the Mille Lacs Lake area.
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 May 26, 10:30 PM CST, 2 hours 20 minutes earlier.
AREA FORECAST DISCUSSION...UPDATED FOR 06Z TAFS NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 1130 PM CDT SAT MAY 26 2012 .DISCUSSION...ISSUED 326 PM CDT PRIMARY FORECAST ISSUE CONTINUE TO BE CONVECTION... BOTH ONGOING ACTIVITY AND POTENTIAL THROUGH THE NEXT 24 TO 36 HOURS. LATEST RADAR IMAGERY SHOWS CONVECTION CONTINUING TO DEVELOP/PERSIST IN AN AREA OF GOOD ISENTROPIC ASCENT NEAR THE MID-LEVEL BAROCLINIC ZONE/FRONTAL BOUNDARY. SEE NO REASON THAT THE ACTIVITY WON/T CONTINUE TO FOCUS AS MID-LEVEL MOISTURE AND ASCENT REMAIN IN PLACE THROUGH THE EVENING. HOWEVER... THE FRONTAL ZONE WILL CONTINUE TO LIFT NORTH/EAST THROUGH THE NIGHT... SO WE SHOULD CONTINUE TO SEE THE BACK EDGE OF THE ACTIVITY WORK ITS WAY NORTH/EAST AS WELL. WATER VAPOR IMAGERY SHOWS AN IMPRESSIVE UPPER TROUGH BEGINNING TO LIFT OUT OF THE SOUTHWEST CONUS... AND THIS WILL BE THE MAIN DRIVER FOR THE SURFACE LOW DEVELOPING IN THE LEE OF THE ROCKIES AND LIFTING NORTHEAST THROUGH THE UPPER PLAINS TOMORROW INTO TOMORROW NIGHT. HOWEVER... OUT AHEAD OF THIS FEATURE THERE ARE A FEW SUBTLE WAVES EVIDENT IN THE WATER VAPOR IMAGERY AND RUC UPPER LEVEL PV ANALYSIS. ONE FEATURE IS MOVING THROUGH FAR WESTERN IOWA AT THE CURRENT TIME... LIKELY HELPING IN SOME OF THE DEVELOPMENT OVER NORTHERN IOWA. A SECOND WAVE CAN BE SEEN FARTHER SOUTH OVER SOUTHERN KANSAS... AND IS ALSO LIFTING NORTH-NORTHEAST. BOTH OF THESE LOOK TO HAVE SOME IMPACT ACROSS OUR AREA THIS EVENING... WHICH IS WHY THERE REMAINS A NEED TO KEEP SOME CHANCE FOR PCPN GOING THROUGH THE EVENING HOURS EVEN THOUGH THE MORE FOCUSED MID-LEVEL FRONT IS MOVING NORTH. THE ACTUAL SURFACE WARM FRONT SHOULD QUICKLY SURGE NORTH OVERNIGHT AS THE MAIN UPPER TROUGH WORKS EAST AND THE 500MB RIDGE AXIS PUSHES NORTHEAST THROUGH THE AREA. WILL BE INTERESTING TO SEE IF/WHEN/WHERE CONVECTION DEVELOPS IN THE WARM SECTOR TO OUR SOUTH LATE THIS AFTERNOON AND EVENING... SINCE THINGS APPEAR FAIRLY WELL CAPPED WITH 700MB TEMPERATURES AOA 13C OVER MUCH OF THE AREA SOUTH OF US. WHAT OCCURS TO OUR SOUTH COULD CERTAINLY IMPACT WHETHER THE ELEVATED CONVECTION OVER OUR AREA PERSISTS... SINCE DEEP CONVECTION TO OUR SOUTH WOULD WORK TO CUTOFF THE BETTER MOISTURE INFLOW. HOWEVER... ACTIVITY THAT DEVELOPS TO OUR SOUTH AND SOUTHWEST COULD ALSO WORK NORTH INTO THE AREA TONIGHT... ADDING AN ADDITIONAL CHALLENGE TO THE FORECAST. FOR TONIGHT... GIVEN THE VARIOUS COMPLICATIONS AND UNKNOWNS MENTIONED ABOVE... TRIED TO FOCUS ON THE PRIMARY LARGE SCALE DRIVERS AND TIED POPS TO THE AREAS OF BETTER FORCING AS SUGGESTED BY THE THALER-QG DIAGNOSTICS FROM THE NAM AND GFS. THAT BEING SAID... SHIFTED THE POPS NORTH THROUGH THE EVENING AND OVERNIGHT HOURS... KEEPING SOME CHANCE GOING THROUGH EVENING ACROSS THE ENTIRE AREA... BUT ALLOWING FOR POP-FREE CONDITIONS OVERNIGHT OVER THE SOUTHEAST PORTION OF THE AREA. ON SUNDAY... WE SHOULD FIND OURSELVES IN THE WARM SECTOR WITH THE WARM FRONTAL BOUNDARY LIFTING NORTH INTO NORTHERN MINNESOTA. THERE COULD CERTAINLY BE SOME LINGERING MORNING CONVECTION IN THE AREA OR SOUTHWEST OF THE AREA... WHICH COULD RESULT IN DEBRIS CLOUDINESS. BUT... DON/T HAVE A STRONG/CONFIDENT OPINION ON THAT AT THIS POINT IN TIME... AND EVEN IF THAT WERE THE CASE WE SHOULD SEE IT DISSIPATE BY LATE MORNING. THAT BEING SAID... EXPECT TO SEE TEMPERATURES WARM NICELY DURING THE DAY WITH DEWPOINTS CLIMBING THROUGH THE 60S... WHICH WILL LEAD TO MLCAPE VALUES AOA 2000 J/KG IN THE AFTERNOON ACROSS MOST OF THE AREA. LOW PRESSURE SHOULD BE WORKING NORTH THROUGH THE PLAINS DURING THE DAY... FINDING ITSELF IN THE DAKOTAS BY AFTERNOON... WORKING TO BRING THE COLD FRONT EAST INTO WESTERN MINNESOTA BY LATE AFTERNOON. THE IS A FAIR DEGREE OF VARIABILITY IN THE MODEL SOLUTIONS WITH RESPECT TO THE POSITION OF THE SURFACE LOW AND FRONTAL BOUNDARIES... MUCH OF WHICH SEEMS TO BE DUE TO THE HANDLING OF CONVECTION BETWEEN NOW AND THEN. GIVEN THE UNCERTAINTY ON HOW THE DETAILS WILL PAN OUT... AND THE UPSCALE CONSEQUENCES... AN ENSEMBLE APPROACH SEEMS MOST PRUDENT AT THIS POINT... SO TENDED TO STICK CLOSE TO THE SREF FOR THE LARGER SCALE DETAILS. THIS WOULD SUGGEST ACTIVITY MAINLY NORTH OF OUR AREA FOR MUCH OF THE DAY... WITH DEVELOPMENT AHEAD OF THE COLD FRONT OVER WESTERN MINNESOTA BY MID AFTERNOON... THEN THINGS WILL PUSH EAST THROUGH THE LATE AFTERNOON AND EVENING... EVENTUALLY WORKING OUT OF THE WISCONSIN PORTION OF THE FORECAST AREA BY MIDNIGHT OR SO SUNDAY NIGHT. WOULDN/T BE SHOCKED TO SEE A COUPLE OF ROUNDS OF ACTIVITY AHEAD OF THE COLD FRONT... WITH SOME INITIAL CONVECTION DEVELOPING IN ASSOCIATION WITH A PRE-FRONTAL TROUGH... THEN A SECONDARY BATCH WITH THE COLD FRONT IF ENOUGH RESIDUAL INSTABILITY REMAINS. SEVERE WEATHER CERTAINLY STILL SEEMS TO BE A GOOD POSSIBILITY SUNDAY AFTERNOON AND EVENING GIVEN THE AMPLE DEGREE OF INSTABILITY AND GOOD FORCING WORKING INTO THE AREA. DEEP LAYER SHEAR IS SOMEWHAT WEAK AT THE TIME CONVECTION IS EXPECTED TO INITIALLY GET GOING... AROUND 30KT... BUT THAT SHOULD STILL BE SUFFICIENT FOR STORM ORGANIZATION GIVEN THE HIGH MLCAPE VALUES EXPECTED. MLCIN ACTUALLY LOOKS TO DECREASE QUITE A BIT DURING THE AFTERNOON... AND WITH DECENT FORCING AHEAD OF THE COLD FRONT... EXPECT CONVECTION TO BECOME WIDESPREAD FAIRLY QUICKLY ONCE IT INITIATES. THIS WOULD SUGGEST THAT ALTHOUGH THERE MAY BE SUFFICIENT SHEAR FOR SUPERCELLS INITIALLY... THINGS ARE LIKELY TO GROW INTO CLUSTERS OR A QLCS OVER TIME... WITH HAIL AND WINDS BEING THE MAIN THREATS. MUCH COOLER AIR WILL WORK INTO THE REGION ON MONDAY AS THE UPPER TROUGH WORKS INTO THE REGION. KEPT SOME POPS ACROSS THE NORTHERN PART OF THE AREA GIVEN THE PROXIMITY OF THE UPPER LOW... AND DEPENDING ON HOW MUCH SUNSHINE WE SEE THERE MAY BE A NEED TO INCLUDE CHANCE POPS FOR MORE OF THE CWFA SINCE ANY HEATING WOULD LIKELY LEAD TO MORE IN THE WAY OF DIURNAL SHRA. THE SAME ACT SHOULD REPEAT ITSELF ON TUESDAY WITH THE UPPER LOW AND MID-LEVEL MOISTURE STILL LINGERING IN THE REGION. AT THIS POINT... OPTED TO GO WITH A DRY FORECAST THROUGH THE BALANCE OF THE WEEK AFTER WE GET ON THE BACKSIDE OF THE UPPER TROUGH AFTER TUESDAY AND A BROAD RIDGE OF SURFACE HIGH PRESSURE SETTLES OVER THE REGION. THE GFS AND ECMWF HINT AT SOME PERIODIC CHANCES FOR PCPN DURING THE THURSDAY THROUGH SATURDAY TIME FRAME AS A FEW SHORTWAVES QUICKLY RIPPLE SOUTHEAST IN THE NORTHWEST UPPER FLOW. THOSE CHANCES WOULD LIKELY BE IN THE SOUTHWEST PORTION OF THE AREA... CLOSER TO THE BAROCLINIC ZONE WHICH WILL BE DEPRESSED TO OUR SOUTHWEST. BUT... AT THIS POINT CHOSE TO LEAVE POPS OUT RATHER THAN BLANKET A 2-3 DAY PERIOD WITH LOW CHANCE VALUES... ESPECIALLY SINCE THERE IS A GOOD DEGREE OF DIFFERENCE BETWEEN THE GFS AND ECMWF AND AMPLE SPREAD IN THE ENSEMBLES. && .AVIATION.../06Z TAF ISSUANCE/ VERY SHORT DISCUSSION DUE TO ONGOING ELEVATED SEVERE STORMS IN CENTRAL MN IN AREA OF VERY STRONG WAA AHEAD OF SFC WARM FRONT. THESE STORMS WILL AFFECT MAINLY THE AXN AND STC TAFS IN THE OVERNITE. MID LVL CAP MAY BE STRONG ENUF TO HOLD IN S AREAS...BUT SOME CONCERN WITH VORT MAX WHICH LIFTED OUT OF KS AND IS NOW W OF DSM WHICH MAY FIRE STORMS IN THE PLUME OF MOISTURE EXTENDING ACRS THE PLAINS INTO S MN. OTHW WRMFNT NOW NEAR IA BORDER WILL LIFT N OVRNIGHT AND SUNDAY MRNG INTO CNTL MN. THIS WILL FOCUS STORMS FOR SUNDAY WITH SECOND FOCUS AHD OF CDFNT PUSHING INTO W MN LATE IN DAY. KMSP...TSTMS IN THE OVRNITE SHUD REMAIN N OF MSP. AREAS OF MVFR CIGS IN THE OVRNITE...BUT IMPRVG CONDS LT TNGHT/ERLY SUNDAY MRNG AS WRMFNT LIFTS N OF AREA. SHUD SEE SLY GUSTS 25 KTS BY 15Z. OUTLOOK... SUN NIGHT...MVFR-IFR WITH TSRA LIKELY. MON...MVFR WITH SHRA POSSIBLE. TUE-WED...VFR WITH PASSING HIGH PRESSURE. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 348 PM CDT SAT MAY 26 2012 MNZ041>045-047>070-073>078-082>085-091>093-WIZ014>016-023>028- 272100- DOUGLAS-TODD-MORRISON-MILLE LACS-KANABEC-STEVENS-POPE-STEARNS- BENTON-SHERBURNE-ISANTI-CHISAGO-LAC QUI PARLE-SWIFT-CHIPPEWA- KANDIYOHI-MEEKER-WRIGHT-HENNEPIN-ANOKA-RAMSEY-WASHINGTON- YELLOW MEDICINE-RENVILLE-MCLEOD-SIBLEY-CARVER-SCOTT-DAKOTA- REDWOOD-BROWN-NICOLLET-LE SUEUR-RICE-GOODHUE-WATONWAN-BLUE EARTH- WASECA-STEELE-MARTIN-FARIBAULT-FREEBORN-POLK-BARRON-RUSK- ST. CROIX-PIERCE-DUNN-PEPIN-EAU CLAIRE- 348 PM CDT SAT MAY 26 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL AND SOUTHERN MINNESOTA... AND WEST CENTRAL WISCONSIN. .DAY ONE...THIS AFTERNOON AND TONIGHT SHOWERS AND THUNDERSTORMS ARE POSSIBLE THROUGH TONIGHT... MAINLY ALONG AND NORTH OF INTERSTATE 94. THESE STORMS COULD PRODUCE LARGE HAIL ALONG WITH HEAVY RAIN. GUSTY WINDS ARE ALSO POSSIBLE. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY SUNDAY WILL BE HOT...WITH AFTERNOON THUNDERSTORMS DEVELOPING IN WESTERN MINNESOTA. LARGE HAIL AND DAMAGING WINDS ARE POSSIBLE... AS WELL AS A FEW TORNADOES. THESE STORMS ALSO COULD PRODUCE HEAVY RAIN AND CAUSE FLASH FLOODING... AS WELL AS FLOODING ALONG THE ALREADY SWOLLEN RIVERS. THE STORMS WILL MOVE EASTWARD DURING THE EVENING AND OVERNIGHT HOURS. .SPOTTER INFORMATION STATEMENT... SKYWARN SPOTTER ACTIVATION MAY BE NEEDED THIS EVENING... AND IS LIKELY SUNDAY AFTERNOON AND EVENING.
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1030 PM CDT SAT MAY 26 2012
MNZ043>045-049>053-061-WIZ014-015-270430-
ANOKA-BARRON-BENTON-CHISAGO-ISANTI-KANABEC-MILLE
LACS-MORRISON-POLK-SHERBURNE-STEARNS-
1030 PM CDT SAT MAY 26 2012
AT 1025 PM CDT...WEATHER SERVICE RADAR WAS TRACKING STRONG
THUNDERSTORMS ALONG A LINE EXTENDING FROM NEAR ST. CLOUD TO
ZIMMERMAN TO NEAR AMERY. THESE STORMS WERE MOVING NORTHEAST AT 35 MPH.
SOME AREAS WHICH COULD BE AFFECT INCLUDE BALSAM LAKE...CAMBRIDGE...
PRINCETON...LINDSTROM...AND RUSH CITY.
HAIL UP TO DIME SIZE IS EXPECTED WITH THESE STORMS.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
&&
LAT...LON 4589 9313 4574 9314 4573 9286 4565 9287
4565 9254 4573 9254 4574 9250 4573 9241
4562 9198 4521 9219 4545 9349 4547 9424
4595 9406
TIME...MOT...LOC 0328Z 218DEG 28KT 4552 9453 4544 9344
4527 9236
BAPSPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1103 PM CDT SAT MAY 26 2012
MNZ041>043-047>050-270500-
BENTON-DOUGLAS-MORRISON-POPE-STEARNS-STEVENS-TODD-
1103 PM CDT SAT MAY 26 2012
AT 1057 PM CDT...WEATHER SERVICE RADAR WAS TRACKING STRONG
THUNDERSTORMS FROM NEAR MORRIS TO NEAR BROOTEN THEN EAST TO THE
PAYNESVILLE AND ST. CLOUD AREA. THESE STORMS WERE MOVING NORTHEAST
AT 30 TO 35 MPH.
SOME COMMUNITIES WHICH MAY BE AFFECTED INCLUDE DONNELLY...GLENWOOD...
SAUK CENTRE...ALBANY...AND ALEXANDRIA.
HAIL UP TO DIME SIZE IS EXPECTED WITH THESE STORMS.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
&&
LAT...LON 4576 9627 4577 9577 4597 9578 4600 9577
4600 9482 4596 9410 4540 9449 4544 9550
4548 9625
TIME...MOT...LOC 0401Z 241DEG 26KT 4554 9651 4549 9537
4546 9449
BAPSPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1241 AM CDT SUN MAY 27 2012
MNZ043>045-050-052-053-270645-
BENTON-CHISAGO-ISANTI-KANABEC-MILLE LACS-MORRISON-
1241 AM CDT SUN MAY 27 2012
AT 1235 AM CDT...WEATHER SERVICE RADAR WAS TRACKING STRONG
THUNDERSTORMS ALONG A LINE EXTENDING FROM NEAR RUM RIVER TO MILACA
TO THE DALBO AND BRAHAM AREAS. THESE STORMS WERE MOVING NORTHEAST
AT 30 MPH.
COMMUNITIES WHICH MAY SEE HAIL UP TO DIME SIZE INCLUDE ONAMIA...
MORA...WARMAN AND ISLE.
LAT...LON 4613 9304 4598 9304 4597 9306 4597 9313
4574 9314 4573 9300 4563 9316 4571 9353
4586 9401 4617 9342 4617 9321
TIME...MOT...LOC 0539Z 248DEG 35KT 4586 9376 4574 9340
4568 9313SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1252 AM CDT SUN MAY 27 2012
MNZ043-044-050-270645-
BENTON-MILLE LACS-MORRISON-
1252 AM CDT SUN MAY 27 2012
AT 1248 AM CDT...WEATHER SERVICE RADAR WAS TRACKING A STRONG
THUNDERSTORM 3 MILES NORTH OF ROYALTON. THIS STORM WAS MOVING
NORTHEAST AT 30 MPH. CIITES WHICH MAY BE AFFECTED INCLUDE THE
LITTLE FALLS AREA...HARDING...AND THE LAKE MILLE LACS AREA.
HAIL UP TO DIME SIZE IS EXPECTED WITH THIS STORM.
LAT...LON 4622 9342 4619 9342 4576 9423 4594 9460
4617 9432 4616 9383 4624 9382 4625 9381
4625 9359
TIME...MOT...LOC 0552Z 224DEG 27KT 4589 9424PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
125 AM CDT SUN MAY 27 2012
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0125 AM HAIL 4 SSW WARMAN 46.01N 93.33W
05/27/2012 M0.50 INCH KANABEC MN TRAINED SPOTTER
&&
CARLYONPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
128 AM CDT SUN MAY 27 2012
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0128 AM HAIL LADYSMITH 45.46N 91.10W
05/27/2012 M0.88 INCH RUSK WI TRAINED SPOTTER
&&
CARLYONThe Duluth radar (KDLH), 128 km away, was scanning. The volume nearest the first event began at 06:48 UTC.
2 thunderstorm wind, 1 flash flood. Local standard time, as filed.
A few large trees were blown down on the southeast part of Lake Mille Lacs.
Several large trees were uprooted near Isle, Minnesota. A trailer court had to be evacuated due to a gas link caused by the downed trees.
Rainfall amounts of two to three inches in less than two hours, caused Highway 27, east of 370th Street to flood during the morning hours of May 27th.
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: 373213, 373214, 378708.