An upper level disturbance tracked along the Canadian border during the late evening of August 1st, helping to push a cold front through the area. Thunderstorms formed over southern Manitoba in advance of the cold front, which eventually moved southeast into portions of Kittson, Roseau, and Lake of the Woods counties.
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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 FGF wrote it up.
An upper level disturbance tracked along the Canadian border during the late evening of August 1st, helping to push a cold front through the area. Thunderstorms formed over southern Manitoba in advance of the cold front, which eventually moved southeast into portions of Kittson, Roseau, and Lake of the Woods counties.
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 Grand Forks, ND wrote its last area forecast discussion before the first event at Aug 1, 8:06 PM CST, 2 hours 30 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 906 PM CDT SAT AUG 1 2015 .UPDATE... ISSUED AT 905 PM CDT SAT AUG 1 2015 QUICK UPDATE... WATCH NUMBER 460 IS CANCELLED FOR ALL AREAS NOW. UPDATE ISSUED AT 832 PM CDT SAT AUG 1 2015 HAVE CANCELLED SEVERE THUNDERSTORM WATCH 460 FOR ALL FGF COUNTIES EXCEPT GRANT COUNTY IN WEST CENTRAL MN. THE WATCH REMAINS IN EFFECT UNTIL MIDNIGHT THO GRANT COUNTY WILL LIKELY BE PULLED OUT BEFORE THEN. MEANWHILE... STORMS ARE FIRING ACROSS SOUTHERN MANITOBA AHEAD OF A FRONTAL BOUNDARY JUST BEGINNING TO DROP SOUTHWARD INTO THE US. HAVE BUMPED UP POPS JUST A BIT ACROSS THE NORTHERN COUNTIES FOR THE EVENING AND OVERNIGHT PERIOD. RISK FOR SEVERE WEATHER IS LOW DUE TO REDUCED CAPE... THOUGH SOME STRONG TSTM OUTFLOW IS POSSIBLE WITH THESE STORMS... AS 0-6KM SHEAR APPROACHES 50KTS. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 325 PM CDT SAT AUG 1 2015 TWO SEPARATE SHORTWAVES WILL AFFECT THE REGION THIS EVENING/OVERNIGHT. THE FIRST WAVE WILL BRING A SEVERE THREAT TO A PORTION OF SE ND AND WC MN. CURRENT SFC ANALYSIS INDICATES A WEAK SFC LOW ACROSS SOUTH-CENTRAL NORTH DAKOTA...WITH A WARM FRONTAL FEATURE EXTENDING TO THE SOUTHEAST. DEWPOINT VALUES ALONG THESE FEATURES HAVE POOLED INTO THE MID-UPPER 60S...LEADING TO MLCAPE 3000-3500 J/KG. AS THIS SYSTEM EVOLVES AND PROPAGATES TOWARD THE FA...ANTICIPATE THUNDERSTORM DEVELOPMENT ACROSS THE FAR SOUTHERN FA. 0-6KM BULK SHEAR 35-40 KNTS COMBINED WITH THE STRONG INSTABILITY WILL LEAD TO SEVERE STORMS...ALTHOUGH COVERAGE SHOULD REMAIN ISOLATED GIVEN CONVECTIVE TEMPS NEAR 90F (SOME CAPPING ISSUES). THIS ACTIVITY WILL MOVE OUT OF THE REGION BY EARLY EVENING. DID ADD T+ (SEVERE STORMS POSSIBLE) ACROSS FAR SE ND WHERE CONFIDENCE IS HIGHER IN THUNDER DEVELOPMENT (LOW LEVEL CONVERGENCE WILL BE MAXIMIZED...AND THE HRRR HAS CONSISTENTLY INDICATED DEVELOPMENT FROM RUN TO RUN). NEXT UP WILL BE THE NORTHERN FA THIS EVENING INTO THE OVERNIGHT HOURS...AS A STRONGER UPPER WAVE BRINGS A COLD FRONT THROUGH THE REGION. THIS ACTIVITY WILL ENCOUNTER WEAK INSTABILITY (MUCAPE 500-1000 J/KG) BUT VERY STRONG DEEP LAYER SHEAR (60+ KNOTS)...ALONG WITH MID-LEVEL WINDS IN EXCESS OF 50 KNTS. THE 18Z HRRR IS INDICATING A SMALL BOW ECHO WITH SFC WIND GUSTS 50-55 KNOTS 02Z-05Z. OF COURSE THAT IS JUST ONE POSSIBLE SOLUTION...BUT IT DOES SPEAK TO THE POTENTIAL OF WHAT COULD OCCUR ACROSS THE NORTHERN FA THIS EVENING AND OVERNIGHT. THIS FORCING MAY ALSO INTERACT WITH INCREASING INSTABILITY FROM THE SOUTH AFTER MIDNIGHT...WHICH MAY BE ENOUGH FOR A FEW STRONGER STORMS INTO THE OVERNIGHT HOURS. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 325 PM CDT SAT AUG 1 2015 THIS PERIOD STARTS OFF WITH A BROAD UPPER LEVEL LOW OVER ONTARIO AND COOL HIGH PRESSURE IN PLACE AT THE SURFACE OVER SASKATCHEWAN AND THE DAKOTAS. THE WEATHER WILL BE DRY AND SLIGHTLY COOLER THAN AVERAGE FOR THE START OF THE WEEK. HOWEVER...A WEAK UPPER LEVEL WAVE WILL MOVE EAST IN THE WEAK UPPER FLOW...UNDERCUTTING A WESTERN U.S. RIDGE BY MID WEEK. THE MODELS HAVE HAD A HARD TIME WITH THIS SYSTEM. PREVIOUS RUNS HAD MORE INSTABILITY AND MUCH MORE OF A PRECIPITATION SIGNAL AREA-WIDE. THE LATEST GFS HAS BEST LIFT/INSTABILITY IN THE FAR SOUTH ON WEDNESDAY NIGHT. SO...CONFIDENCE IS DECREASING IN WEDNESDAYS SYSTEM. ANOTHER WEAK WAVE WILL AFFECT PRIMARILY THE SOUTH ON THURSDAY...BUT AGAIN...THIS ONE HAS TRENDED SOUTHWARD. HOWEVER...FRIDAYS SYSTEM LOOKS TO BE THE WAVE THAT HAS THE MOST AGREEMENT REGARDING TRACK AND COULD BRING WIDESPREAD PRECIP TO THE AREA. WITH PLENTY OF UNCERTAINTY ON THESE WAVES...TOO EARLY TO TALK ABOUT SEVERE POTENTIAL. PRECIPITATION CHANCES EXIST INTO SATURDAY AS WELL AND WILL DEPEND ON SPEED OF UPPER LOW. TEMPERATURES LOOK TO BE COOL FOR MUCH OF THIS PERIOD. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) UPDATED AT 835 PM CDT SAT AUG 1 2015 GENERALLY FAIR SKIES THROUGH THE EVENING AND OVERNIGHT ACROSS THESOUTHERN FA AS SEVERE THUNDERSTORM THREAT THERE IS NOW MINIMAL. MEANWHILE... A WEAK COLD FRONT WILL DROP FROM SOUTHERN SASK AND MANITOBA ACROSS THE NORTHERN HALF OF THE FA... ALG AND NORTH OF A CANDO TO GRAND FORKS AND BEMIDJI LINE... WITH SCATTERED SHOWERS AND AN ISOLATED MVFR CIG AND VSBY IN STRONG THUNDERSTORMS IN THE MIX. SCATTERED SHOWERS SHOULD PERSIST INTO THE MORNING HOURS ACROSS NORTHERN MN. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && UPDATE...GUST SHORT TERM...TG LONG TERM...KNUTSVIG AVIATION...GUST
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GRAND FORKS ND 1132 AM CDT SAT AUG 1 2015 MNZ001>009-013>017-022>024-027>032-040-NDZ006>008-014>016-024- 026>030-038-039-049-052>054-021200- WEST POLK-NORMAN-CLAY-KITTSON-ROSEAU-LAKE OF THE WOODS- WEST MARSHALL-EAST MARSHALL-NORTH BELTRAMI-PENNINGTON-RED LAKE- EAST POLK-NORTH CLEARWATER-SOUTH BELTRAMI-MAHNOMEN- SOUTH CLEARWATER-HUBBARD-WEST BECKER-EAST BECKER-WILKIN- WEST OTTER TAIL-EAST OTTER TAIL-WADENA-GRANT-TOWNER-CAVALIER- PEMBINA-BENSON-RAMSEY-EASTERN WALSH COUNTY-EDDY-NELSON- GRAND FORKS-GRIGGS-STEELE-TRAILL-BARNES-CASS-RANSOM-SARGENT- RICHLAND-WESTERN WALSH COUNTY- 1132 AM CDT SAT AUG 1 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN NORTH DAKOTA...WEST CENTRAL AND NORTHWEST MINNESOTA. .DAY ONE...THIS AFTERNOON AND TONIGHT ISOLATED SEVERE STORMS ARE POSSIBLE ACROSS A PORTION OF SOUTHEAST NORTH DAKOTA AND WEST CENTRAL MINNESOTA FROM LATE AFTERNOON INTO THE EARLY EVENING HOURS. HAIL GREATER THAN ONE INCH AND DAMAGING WIND GUSTS WILL BE THE MAIN THREATS. ADDITIONAL THUNDERSTORMS ARE EXPECTED ACROSS A PORTION OF NORTHEAST NORTH DAKOTA INTO NORTHWEST MINNESOTA TONIGHT. ALTHOUGH THE THREAT FOR SEVERE STORMS WITH THIS ACTIVITY IS LOW...THE POTENTIAL FOR STRONGER WIND GUSTS WILL EXIST. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT ANTICIPATED. TG
The Fargo/Grand Forks radar (KMVX), 153 km away, was scanning. The volume nearest the first event began at 04:37 UTC.
7 thunderstorm wind, 3 hail. Local standard time, as filed.
The hail was accompanied by strong winds and heavy rain, which knocked down some small tree branches.
The strong winds blew down some four inch diameter tree branches and stripped plant foliage in the area.
Dime to nickel sized hail was reported.
The wind gust was measured at the Roseau airport.
A large tree was blown down.
Trees were knocked over by the strong wind.
Heavy rain and small hail were accompanied by driving winds. A few four inch diameter tree branches were blown down and garden furniture was scattered.
A few five inch diameter tree branches were blown down. Heavy rain also occurred.
A pine tree was blown down onto a house.
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: 584409, 584411, 584412, 584414, 584415, 584416, 584417, 584418, 584419, 584421.