This event set up as another nice case of elevated convection. On the morning of the 20th, an area of surface low pressure was located near Mobridge, South Dakota, with a warm front arching to the southeast (down into eastern Nebraska).
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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.
This event set up as another nice case of elevated convection. On the morning of the 20th, an area of surface low pressure was located near Mobridge, South Dakota, with a warm front arching to the southeast (down into eastern Nebraska). A 35 to 45 knot low level jet set up from central Nebraska into northeast South Dakota, where there was also a tight moisture gradient at 850 mb. Thunderstorms initially flared up near Crookston, MN, and moved northeast at 40 to 50 mph.
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 Sep 20, 8:30 AM CST, 1 hour earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 930 AM CDT THU SEP 20 2007 FORECAST CHALLENGE FOR UPDATE CONCERNS PCPN CHANCES/COVERAGE AND INTENSITY AS WELL AS TEMPERATURES. CONVECTIVE COMPLEX OVER NE SD/SE ND AND WEST CENTRAL MN DRIVEN BY MID LEVEL SHORTWAVE LIFTING NORTHEAST AND IMPRESSIVE LOW LEVEL JET CONVERGENCE IN WARM ADVECTION ZONE. STRONGEST WARM ADVECTION AND CONVERGENCE WITH LOW LEVEL JET GRADUALLY SHIFTS E DURING DAY SO EXPECT CONVECTION TO FOLLOW. HAVE RECONFIGURED POPS BASED ON CURRENT RADAR TRENDS AND EXPECTED PROPAGATION KEEPING HIGHEST POPS ACROSS E-SE FA. DID NOT MAKE MAJOR CHANGES TO CURRENT MID RANGE AFTERNOON POPS AS WILL HAVE TO SEE HOW FAR WARM FRONTAL BOUNDARY LIFTS NORTH AND DEGREE OF INSOLATION TO DESTABILIZE COLUMN. WITH DEGREE OF UNCERTAINTY ON SOLAR POTENTIAL WILL LEAVE TEMPERATURES AS IS. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && VOELKER
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GRAND FORKS ND 504 AM CDT THU SEP 20 2007 MNZ001>009-013>017-022>024-027>032-040-NDZ006>008-014>016-024- 026>030-038-039-049-052>054-211015- 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- 504 AM CDT THU SEP 20 2007 ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN NORTH DAKOTA AND WEST CENTRAL AND NORTHWEST MINNESOTA... THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN NORTH DAKOTA...WEST CENTRAL AND NORTHWEST MINNESOTA. .DAY ONE...TODAY AND TONIGHT THERE IS A SLIGHT CHANCE FOR SEVERE THUNDERSTORMS TODAY INTO THIS EVENING FOR AREAS GENERALLY SOUTH AND EAST OF A LINE FROM GRAND FORKS TO VALLEY CITY. THE MAIN THREAT FROM THE STORMS WILL BE LARGE HAIL AND DAMAGING WINDS HOWEVER AN ISOLATED TORNADO CANNOT BE RULED OUT FROM THE SOUTHERN RED RIVER VALLEY INTO WEST CENTRAL MINNESOTA. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY THERE IS A CHANCE FOR THUNDERSTORMS LATE SATURDAY NIGHT INTO EARLY NEXT WEEK. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE REQUIRED. IN ADDITION THE PUBLIC IS ENCOURAGED TO REPORT ANY SEVERE WEATHER REPORTS TO THE NATIONAL WEATHER SERVICE. BERG
The Aberdeen radar (KABR), 202 km away, was scanning. The volume nearest the first event began at 15:30 UTC.
5 hail, 1 lightning. Local standard time, as filed.
Lightning struck an evergreen tree in Barrett, scattering pieces of the tree across several neighboring yards. As the tree fell, it broke multiple windows and damaged the concrete steps to a house. The strike also damaged the electrical systems in three nearby homes. One home lost a microwave, two televisions, and several other smaller appliances.
The ground was covered with hail.
Hail covered the ground.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Minnesota in 2007Every state in 2007This day in weather historyWarnings in Minnesota, September 2007
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: 54686, 54675, 54676, 54677, 54679, 54680.