A weak surface low that was centered across eastern North Dakota, moved slowly southeast across western Minnesota during the afternoon of Saturday, April 21st. Afternoon sunshine, combined with a fairly sheared environment below 3 km, allowed for a few severe thunderstorms to develop along the sharp wind shift line from the southeast, to the northwest.
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.
A weak surface low that was centered across eastern North Dakota, moved slowly southeast across western Minnesota during the afternoon of Saturday, April 21st. Afternoon sunshine, combined with a fairly sheared environment below 3 km, allowed for a few severe thunderstorms to develop along the sharp wind shift line from the southeast, to the northwest. Enhanced wind shear in the lowest 1 km along this wind shift line, with the development of thunderstorms, caused a few tornadoes to form. Most of the tornadoes were brief touchdowns, and damage was confined to barns and outbuildings. Some hail also accompany the thunderstorms, which generated penny, to occasional nickel size hail.
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 Apr 21, 11:40 AM CST, 59 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 1240 PM CDT SAT APR 21 2012 .AVIATION... /18Z TAF ISSUANCE/ MAIN AVIATION CONCERN EARLY IS THUNDER THREAT OVER WESTERN AREAS THROUGH ABOUT 00Z. VIGOROUS VORT DROPPING SOUTHEAST OVER THE WESTERN PORTION OF THE AREA THROUGH THE AFTERNOON. LOWER BOUNDARY LAYER INSTABILITY HAS INCREASED AND MID LEVEL LAPSE RATES UNSTABLE. ISOLD/SCT THUNDER A GOOD BET OVER WESTERN AREAS ALONG CLOUD EDGE AND AHEAD OF SECONDARY FRONT DROPPING OVER THE EASTERN DAKOTAS. SOME SMALL HAIL AND GUSTY WINDS POSSIBLE IN THE STRONGER STORMS. LOOKS LIKE BEST POTENTIAL FOR THUNDER AT KRWF LATER THIS AFTERNOON AND MENTIONED TEMP TSRA THERE. OTHERWISE...SHOWERS/LIGHT RAIN EXPECTED FARTHER EAST OVER CENTRAL/EASTERN MN AND ALONG THE MN/WI BORDER. KEAU MAY MISS OUT ON RAIN ALTOGETHER...WILL BE CLOSE. CEILINGS DROPPING MVFR WITH SOME ISOLD IFR YET INT COOLER AREAS OF CENTRAL MN. THIS WILL WORK EAST DURING THE AFTERNOON AS WELL...AFFECTING KSTC. CEILINGS EXPECTED TO DROP TO LOW END MVFR TO IFR OVER CENTRAL MN DURING THE NIGHT AS TROUGH AXIS REMAINS IN THE VICINITY. PRECIPITATION SHOULD TAPER OFF TO FOG/DRIZZLE THIS EVENING NEAR THE BOUNDARY. EXPECT CEILINGS TO GRADUALLY LIFT SUNDAY MORNING...BECOMING VFR MOST AREAS THROUGH 15Z SUNDAY. WINDS SHOULD REMAIN SOUTH/SOUTHEAST THIS AFTERNOON AHEAD OF BOUNDARY BECOMING MORE EASTERLY OVERNIGHT AS SURFACE LOW DROPS SOUTH OVER THE AREA. WINDS WILL BECOME NORTHWEST AND GUSTY FAR WESTERN AREAS IN THE WAKE OF THE LOW. KMSP...VFR CEILING EXPECTED EARLY THIS AFTERNOON...BUT DROPPING TO MVFR THROUGH 19Z-20Z AS THE RAIN AREA MOVES THROUGH. CEILINGS MAY DROP OFF TO 1500 FEET BY EARLY EVENING AS MAIN RAIN AREA EXITS. LEFTOVER LIGHT RAIN/DRIZZLE EXPECTED TO PIVOT WEST THEN IN WAKE OF SURFACE LOW WITH GRADUALLY IMPROVING CONDITIONS TO VFR BY SUNDAY MORNING. SOUTH/SOUTHEAST WINDS THIS AFTERNOON/EVENING BECOMING EAST/NORTHEAST LATE TONIGHT/SUNDAY MORNING. //OUTLOOK...MONDAY THROUGH WEDNESDAY... MON-VFR. TUE-TUE NITE...VFR BECOMING MVFR WITH CHC OF -SHRA ISOLD TSRA. WED...CHANCE -SHRA WITH MVFR CIGS. && .DISCUSSION... /ISSUED 244 AM CDT SAT APR 21 2012/ CURRENT REGIONAL RADAR HAS THE BEST CONCENTRATION OF SHRA/TSRA ACROSS EASTERN SD...WHICH IS RELATED TO A SHRTWV ACROSS SC ND AS OF 2 AM. MOST OF THE MODELS DOWNPLAYED THIS AREA OF SHRA WHICH IS A CONCERN IN THE SHORT TERM FOR AREAS IN THE SW FA. HOWEVER...THE NEXT SHRTWV IS NOTED ON WV IMAGERY...JUST NORTH OF ND WHICH WILL LIKELY BE THE MAIN FORCING FOR THIS MORNING/AFTN ACROSS MOST OF MY FA. THERE ARE SOME INDICATIONS THAT MORE SHRA ARE DEVELOPING AHEAD OF THIS WAVE ACROSS EASTERN ND WHICH LEADS TO BETTER CONFIDENCE IN THE SHORT TERM FORECAST. BASICALLY...A BROAD AREA OF SHRA WILL COMMENCE THIS MORNING ACROSS THE W FA...THEN SPREAD EASTWARD AS THE SHRTWV AND ASSOCIATED LIFT/MOISTURE INTERACT TO PRODUCE A CONCENTRATED AREA OF SHRA. BY THE LATE MORNING/EARLY AFTN...MOST OF THE SIGNIFICANT FORCING MOVES EAST OF THE FAR SW FA WHICH LEADS TO LESS CLOUD COVER. IN ADDITION...LATEST INDICATIONS OF BETTER INSTABILITY DEVELOPS IN THE FAR SW FA BY THE AFTN. THIS WOULD LEAD TO ISOLATED TSRA...BUT COVERAGE WILL LIKELY BE LOWER. ANOTHER ASPECT TO THIS SHRTWV IS THIS BEST LIFT OCCURS BEFORE 00Z/22...WITH ONLY A SFC TROUGH REFLECTION AND WEAK CONVERGENCE BLW 70H TO CREATE ANY TYPE OF PRECIPITATION. THIS TYPE OF SFC REFLECTION/INVERTED TROUGH WILL LIKELY BE THE KEY OF ISOLATED/SCATTERED -RA AND PERSISTENT CLD CVR THRU SUNDAY. LATER SHIFTS CAN SEE WHERE THE WEAK CONVERGENCE DEVELOPS AND ASSOCIATED PRECIPITATION OCCURS FOR LATE TONIGHT/SUNDAY FOR POPS/QPF AMTS. ANOTHER CONCERN IS THE CONTINUED SHRTWV ENERGY DIVING SSE ACROSS THE FA AS THE TROUGH CONTINUES TO DEEPEN IN THE EASTERN 1/3 OF THE NATION. ONCE THE MAIN WAVE MOVES EAST OF OUR REGION...AND THE UPPER JET IS MORE ORIENTED ACROSS WI...THERE SHOULD BE A DRY PERIOD FOR A DAY OR SO. UNCERTAINTIES DEVELOP BY MIDWEEK AS THE UPPER RIDGE BEGINS TO BREAK DOWN IN THE WEST...AND THE LONG WAVE TROUGH REMAINS FOCUS ACROSS THE EAST COAST AND EASTERN CANADA. THERE MAY BE A FRONTAL BOUNDARY AND ASSOCIATED PRECIPITATION FIELD ON TUE NIGHT/WED AS A SECONDARY COOLER AIR MASS BEGINS TO SLIDE SOUTHWARD FROM CANADA...BUT THIS HAS NOT BEEN THE CASE FROM PREVIOUS MODEL RUNS. THEREFORE...CONFIDENCE REMAINS LOW PAST MONDAY FOR ANY TYPE OF TEMP/PRECIPITATION TRENDS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && RAH/JLT
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 1158 AM CDT SAT APR 21 2012 MNZ041>045-049>053-059>063-068>070-076>078-084-085-093-WIZ014>016- 023>028-221700- DOUGLAS-TODD-MORRISON-MILLE LACS-KANABEC-STEARNS-BENTON-SHERBURNE- ISANTI-CHISAGO-WRIGHT-HENNEPIN-ANOKA-RAMSEY-WASHINGTON-CARVER- SCOTT-DAKOTA-LE SUEUR-RICE-GOODHUE-WASECA-STEELE-FREEBORN-POLK- BARRON-RUSK-ST. CROIX-PIERCE-DUNN-PEPIN-CHIPPEWA-EAU CLAIRE- 1158 AM CDT SAT APR 21 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL MINNESOTA...EAST CENTRAL MINNESOTA...SOUTH CENTRAL MINNESOTA... SOUTHEAST MINNESOTA...WEST CENTRAL MINNESOTA...NORTHWEST WISCONSIN AND WEST CENTRAL WISCONSIN. .DAY ONE...THIS AFTERNOON AND TONIGHT NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY THUNDERSTORMS ARE POSSIBLE ON TUESDAY INTO TUESDAY NIGHT. THE THREAT FOR SEVERE WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SKYWARN SPOTTER ACTIVATION WILL NOT BE NEEDED. MNZ047-048-054>058-064>067-073>075-082-083-091-092-221700- STEVENS-POPE-LAC QUI PARLE-SWIFT-CHIPPEWA-KANDIYOHI-MEEKER- YELLOW MEDICINE-RENVILLE-MCLEOD-SIBLEY-REDWOOD-BROWN-NICOLLET- WATONWAN-BLUE EARTH-MARTIN-FARIBAULT- 1158 AM CDT SAT APR 21 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL MINNESOTA...SOUTH CENTRAL MINNESOTA...SOUTHWEST MINNESOTA AND WEST CENTRAL MINNESOTA. .DAY ONE...THIS AFTERNOON AND TONIGHT ISOLATED THUNDERSTORMS ARE POSSIBLE DEVELOPING OVER WEST CENTRAL MINNESOTA THIS AFTERNOON AND MOVING INTO SOUTH CENTRAL MINNESOTA BY EVENING. SEVERE WEATHER IS NOT EXPECTED AT THIS TIME ALTHOUGH SMALL HAIL AND WIND GUSTS TO 40 MPH ARE POSSIBLE IN THE STRONGER STORMS THAT DO DEVELOP. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY THUNDERSTORMS ARE POSSIBLE ON TUESDAY AND TUESDAY NIGHT. THE THREAT FOR SEVERE WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SKYWARN SPOTTER ACTIVATION WILL NOT BE NEEDED.
The Aberdeen radar (KABR), 171 km away, was scanning. The volume nearest the first event began at 18:38 UTC.
5 tornado, 4 hail, 4 funnel cloud. Local standard time, as filed.
A tornado touchdown briefly approximately 3 miles northwest of Chokio, Minnesota. The report is based on a storm chaser's photo. No damage occurred and the tornado lifted quickly.
Several witness and the local law enforcement confirmed that a tornado touchdown approximately 3.0 miles southwest of Big Bend City, near Highway 40, and tracked southeast, for a half mile before lifting. Based on damage from a barn and grainery, the tornado was rated an EF0 with wind speeds of 75 mph.
Several witnesses and storm spotters observed a tornado touchdown south of Lucan, Minnesota. The tornado tracked to the southeast and damaged a farmhouse, which included several outbuildings, a greenhouse, pole barn, and shed. Based on damage the tornado was rated an EF0 with top winds of 80 mph. The tornado lifted one quarter of a mile southeast of the farmhouse where debris was thrown one half mile.
Local law enforcement reported a tornado briefly touched on several occasions approximately 6 miles east-northeast of Big Bend City, Minnesota. No damage was reported.
Storm spotters sighted numerous funnel clouds across Redwood County for 15 to 20 minutes.
Local law enforcement officials confirmed that a tornado briefly touched down northeast of Farwell, Minnesota. Based on damage of a 30-40 foot pole barn, and minor damage to a second barn, the tornado was rated an EF0 with top winds of 75 mph.
Storm spotters observed a funnel cloud northwest of Clara City, Minnesota.
A funnel cloud was reported north of Renville.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Minnesota in 2012Every state in 2012This day in weather historyThe tornado archive for Minnesota, 2012Warnings in Minnesota, April 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: 369833, 366552, 366558, 366553, 366556, 366557, 366550, 366559, 366551, 366554, 373678, 373679, 369836.