The first severe thunderstorms that developed across far northwest Minnesota during the early evening of Wednesday, August 12th, moved into northern Morrison County and produced baseball size hail in Camp Ripley. This storm moved southward into southern Morrison County and dissipated.
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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 MPX wrote it up.
The first severe thunderstorms that developed across far northwest Minnesota during the early evening of Wednesday, August 12th, moved into northern Morrison County and produced baseball size hail in Camp Ripley. This storm moved southward into southern Morrison County and dissipated. Other storms that developed in northern Minnesota later the same night, moved into Todd and Douglas Counties and produced some hail and wind damage during the morning hours of Thursday, August 13th. These storms moved southward and weakened as they moved toward the Twin Cities metro area.
Scattered showers from decaying thunderstorms earlier across central Minnesota moved rapidly south across Isanti County, and brought brief wind gusts over 50 mph and caused several trees to blow down in the city of Cambridge.
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 Aug 12, 5:20 PM CST, 2 hours 44 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 620 PM CDT WED AUG 12 2015 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 227 PM CDT WED AUG 12 2015 PRIMARY CONCERN IN THE SHORT TERM IS THETA-E RIDGE AND ASSOCIATED INSTABILITY WORKING INTO THE AREA ON THE BACKSIDE OF THE SURFACE HIGH... AND A WEAK SURFACE TROUGH DROPPING THROUGH THE AREA TONIGHT AND THURSDAY. THE PRIMARY LARGE SCALE FORCING FOR ASCENT LOOKS TO REMAIN NORTH/NORTHEAST OF OUR AREA... WHICH SHOULD BE THE FOCUS FOR MORE WIDE SPREAD PCPN AND HIGHER POPS. HOWEVER... SCATTERED CONVECTION STILL LOOKS LIKE IT SHOULD BE ABLE TO GET GOING TO OUR NORTHWEST BY EARLY EVENING... WHICH WOULD THEN MOVE SOUTHEAST THROUGH THE OVERNIGHT HOURS. THE ACTIVITY LOOKS LIKE IT WOULD BE MOVING OUT OF THE BEST MOISTURE TRANSPORT... AND WOULD BE GETTING OUT AHEAD OF ANY LOW LEVEL FORCING... BUT WOULD LIKELY BE ABLE TO SUSTAIN ITSELF AT LEAST INTO THE CENTRAL PORTION OF THE AREA OVERNIGHT. SO... ALLOWED FOR CHANCE POPS TO MOVE ACROSS A GOOD PART OF THE AREA FROM LATE EVENING THROUGH THE OVERNIGHT. SUBSEQUENT UPDATES MAY NEED TO BUMP THINGS UP DEPENDING UPON HOW ACTIVITY EVOLVES TONIGHT. ANY SEVERE WEATHER THREAT SHOULD BE CONFINED TO THE NORTHERN PORTION OF THE AREA AND BE MAINLY A HAIL AND WIND ISSUE. IF CONVECTION IS ABLE TO GROW UPSCALE INTO AN MCS... WHICH DOESN/T APPEAR TOO LIKELY AT THIS POINT... THEN A WIND THREAT COULD PERSIST FARTHER SOUTH/EAST INTO THE AREA THROUGH THE OVERNIGHT HOURS. WE MAY SEE SOME REDEVELOPMENT OVER THE SOUTHERN PORTION OF THE AREA THURSDAY AFTERNOON NEAR THE SURFACE THROUGH... THEN ACROSS MORE OF THE AREA THURSDAY EVENING AS A SHORTWAVE MOVES INTO THE AREA FROM THE PLAINS. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 227 PM CDT WED AUG 12 2015 THE MAIN THEME OF THE EXTENDED PERIOD WILL BE FOR THE WESTERN/CENTRAL CONUS RIDGE TO BE FLATTENED OUT AS SUCCESSIVE SHORTWAVES MOVE EAST ALONG THE INTERNATIONAL BORDER... WITH HEIGHTS CONTINUING TO LOWER ACROSS THE NORTHERN CONUS THROUGH THE MIDDLE OF NEXT WEEK. THIS WILL INITIALLY LEAD TO OUR INCREASING WARMTH AND HUMIDITY FOR A COUPLE OF DAYS... THEN COOLER TEMPERATURES FOR NEXT WEEK. THE MAIN FEATURE OF INTEREST STILL LOOKS LIKE IT WILL BE A COLD FRONT MOVING THROUGH THE REGION ON SUNDAY. THE GFS HAS SLOWED DOWN... AND IS NOW VERY SIMILAR TO THE ECMWF AND GEM WITH THE TIMING OF THE FROPA ON SUNDAY... WITH IT IN THE WESTERN FORECAST AREA AROUND 12Z THEN INTO THE EASTERN AREA BY 00Z. ITS PROGRESSION DOES LOOK TO SLOW WITH TIME AS THE MID-LEVEL WINDS BECOME MORE PARALLEL TO THE FRONT. HOWEVER... IT DOESN/T LOOK LIKE IT WILL STALL OUT TOO CLOSE TO THE AREA... SO WE SHOULD HAVE DRY WEATHER OVER MOST OF THE AREA FROM MONDAY THROUGH A GOOD PART OF TUESDAY. DID KEEP SOME LOW POPS OVER THE SOUTH ON MONDAY... WITH THE BOUNDARY BEING CLOSEST TO THAT PORTION OF THE AREA... BUT WOULDN/T BE SURPRISED IF SUBSEQUENT FORECASTS ARE ABLE TO REMOVE THAT. THE NEXT ITEM OF CONCERN COMES AT THE TAIL END OF THE FORECAST PERIOD... WITH DECENT AGREEMENT BETWEEN THE GFS... ECMWF... AND GEFS ON A STRONG SHORTWAVE MOVING INTO THE PLAINS ON WEDNESDAY WITH AN ASSOCIATED SURFACE LOW. WARM FRONTAL BOUNDARY LOOKS LIKE IT WOULD BE LIFTING NORTH THROUGH THE AREA DURING THE DAY ON WEDNESDAY... AND THE SYSTEM APPEARS AS LOW IT MIGHT BE SOMEWHAT SLOW TO MOVE EASTWARD GIVEN THE AMPLITUDE OF THE UPPER WAVE... SO IT COULD BE A WET PERIOD SOMEWHERE IN THE REGION FROM LATE TUESDAY INTO THURSDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING) ISSUED AT 620 PM CDT WED AUG 12 2015 A FEW STRONG STORMS ARE MOVING SOUTHWARD THROUGH NORTHERN MN CURRENTLY...AND COULD IMPACT STC AND POSSIBLY AXN LATER TONIGHT. THE STORMS SHOULD WEAKEN SOMEWHAT AFTER SUNSET...BUT CANNOT RULE OUT A BRIEF SHOWER OR STORM OVERNIGHT ACROSS EASTERN MN AND WESTERN WI. FROM THURSDAY MORNING THROUGH THE END OF THE TAF PERIOD...VFR IS EXPECTED TO PREVAIL AT ALL TERMINALS. SOUTHWEST WINDS OVERNIGHT THROUGH THURSDAY MORNING WILL BECOME WESTERLY BY THURSDAY AFTERNOON...AND GENERALLY HOVER AROUND 10 KTS. KMSP...VFR SHOULD PREVAIL THROUGH THE PERIOD...THOUGH A BRIEF SHOWER OR THUNDERSTORM CANNOT BE RULED OUT OVERNIGHT THROUGH EARLY THURSDAY MORNING. WIND DIRECTION WILL START OUT FROM THE SOUTH- SOUTHWEST AT 190-200 DEGREES OVERNIGHT...AND WILL BECOME SOUTHWESTERLY BY MID-MORNING AND WESTERLY BY THE EARLY AFTERNOON. WIND SPEED SHOULD REMAIN AROUND 10 KTS THROUGH THURSDAY EVENING. /OUTLOOK FOR KMSP/ FRIDAY...VFR. WEST TO NORTHWEST WIND 5 KT OR LESS. FRIDAY NIGHT...VFR. LIGHT AND VARIABLE WIND BECOMING SOUTHEAST 5 TO 10 KT. SATURDAY...VFR SOUTHEAST WIND 5 TO 10 KT BECOMING SOUTHWEST 15 TO 25 KT. SATURDAY NIGHT...MVFR CEILINGS AND VISIBILITIES POSSIBLE WITH A CHANCE OF SHRA/TSRA. SOUTHWEST WIND 10 TO 20 KT. SUNDAY...MVFR CEILINGS AND VISIBILITIES EXPECTED WITH A CHANCE OF SHRA/TSRA... BRIEF IFR CONDITIONS POSSIBLE. SOUTHWEST WIND 10 TO 20 KT BECOMING WEST. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && SHORT TERM... LONG TERM... AVIATION...ADL
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 657 PM CDT WED AUG 12 2015 MNZ047-054>057-064-065-067-073>078-082>085-091>093-131715- STEVENS-LAC QUI PARLE-SWIFT-CHIPPEWA-KANDIYOHI-YELLOW MEDICINE- RENVILLE-SIBLEY-REDWOOD-BROWN-NICOLLET-LE SUEUR-RICE-GOODHUE- WATONWAN-BLUE EARTH-WASECA-STEELE-MARTIN-FARIBAULT-FREEBORN- 657 PM CDT WED AUG 12 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL MINNESOTA...SOUTH CENTRAL MINNESOTA...SOUTHEAST MINNESOTA... SOUTHWEST MINNESOTA AND WEST CENTRAL MINNESOTA. .DAY ONE...TONIGHT. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. THERE IS A CHANCE FOR THUNDERSTORMS THURSDAY INTO THURSDAY NIGHT AND AGAIN SATURDAY NIGHT INTO SUNDAY. THE THREAT FOR SEVERE WEATHER APPEARS LOW AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SKYWARN SPOTTER ACTIVATION IS NOT EXPECTED TO BE NEEDED TONIGHT. MNZ041>045-048>053-058>063-066-068>070-WIZ014>016-023>028-131715- DOUGLAS-TODD-MORRISON-MILLE LACS-KANABEC-POPE-STEARNS-BENTON- SHERBURNE-ISANTI-CHISAGO-MEEKER-WRIGHT-HENNEPIN-ANOKA-RAMSEY- WASHINGTON-MCLEOD-CARVER-SCOTT-DAKOTA-POLK-BARRON-RUSK-ST. CROIX- PIERCE-DUNN-PEPIN-CHIPPEWA-EAU CLAIRE- 657 PM CDT WED AUG 12 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL MINNESOTA...EAST CENTRAL MINNESOTA...WEST CENTRAL MINNESOTA... NORTHWEST WISCONSIN AND WEST CENTRAL WISCONSIN. .DAY ONE...TONIGHT. A FEW THUNDERSTORMS ARE POSSIBLE THIS EVENING INTO THE OVERNIGHT HOURS...MAINLY AROUND AND NORTH OF THE INTERSTATE 94 CORRIDOR. ISOLATED STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE. MAIN HAZARDS ARE LARGE HAIL AND DAMAGING WINDS. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. THERE IS A CHANCE FOR THUNDERSTORMS THURSDAY INTO THURSDAY NIGHT AND AGAIN SATURDAY NIGHT INTO SUNDAY. THE THREAT FOR SEVERE WEATHER APPEARS LOW AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SKYWARN SPOTTER ACTIVATION MAY BE NEEDED TONIGHT.
The Minneapolis radar (KMPX), 169 km away, was scanning. The volume nearest the first event began at 02:02 UTC.
2 hail, 2 thunderstorm wind, 1 strong wind. Local standard time, as filed.
Baseball size hail fell in Camp Ripley during the evening of Wednesday, August 12th. The next morning, golf ball size hail was still in the ditches where the large hail fell the night before.
A few trees were uprooted north of Browerville on Highway 71.
A few large trees were blown down with one tree taking down a power line.
Local officials in Isanti County indicated that non-thunderstorm wind gusts occurred around the city of Cambridge and caused several large tree limbs, and small trees to blow down and block city roads. No injuries were reported.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Minnesota in 2015Every state in 2015This day in weather historyWarnings in Minnesota, August 2015
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: 587683, 587684, 587686, 587685, 587929.