For having such weak overall features, this event produced some very large hail. The surface map showed a weak low pressure system over central North Dakota with a weak wind field.
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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.
For having such weak overall features, this event produced some very large hail. The surface map showed a weak low pressure system over central North Dakota with a weak wind field. However, precipitable water values were very high and storm movement was slow. Just enough low level jet energy helped spawn the widely scattered showers and thunderstorms.
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 Jun 20, 7:50 PM CST, 5 hours 10 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 850 PM CDT SUN JUN 20 2010 .DISCUSSION... FORECAST CHALLENGE OVERNIGHT REMAINS CHANCE OF THUNDERSTORMS FOR PORTIONS OF THE FORECAST AREA. A WEAK LINE OF THUNDERSTORMS EARLIER THIS EVENING ACROSS SOUTHERN MANITOBA...WHICH CLIPPED LAKE OF THE WOODS...CONTINUES TO WEAKEN AS THE BEST INSTABILITY REMAINS FAR TO THE SOUTH. 00Z KBIS AND KABR SOUNDINGS SHOWING IMPRESSIVE INSTABILITY WITH LIFTED INDEX VALUES NEAR -8C AND SPC MIXED LAYER CAPE OF AROUND 2500 J/KG FOR BOTH AREAS. HOWEVER...THE INSTABILITY DECREASES RAPIDLY TO THE NORTHEAST AS YOU MOVE INTO NORTHERN MINNESOTA. CURRENT FORECAST GRIDS HAVE CHANCE THUNDERSTORM PERCENTAGES IN THE WESTERN AND SOUTHERN PORTIONS OF THE FA WHICH APPEAR REASONABLE. DUE TO RELATIVELY WEAK FLOW ALOFT...CELL MOVEMENT HAS BEEN VERY SLOW. LOCALIZED HEAVY RAINFALL HAS OCCURRED WITHIN THE BIS FA...IN LAMOURE AND DICKEY COUNTIES...WHERE PERSISTENT SLOW MOVING CELLS HAVE REMAINED FOR THE LAST 2 HOURS. ANY THUNDERSTORMS WHICH DEVELOP IN THE FA OVERNIGHT WILL NEED TO BE MONITORED FOR STORM TOTAL RAINFALL. OTHERWISE...THE FORECAST LOOKS TO BE ON TRACK. THUS...NO EVENING UPDATE PLANNED. && .AVIATION... VFR CONDITIONS EXPECTED THROUGH 00Z TUESDAY. THUNDERSTORM CHANCES OVERNIGHT APPEAR TO BE BEST IN THE WESTERN AND SOUTHERN PORTIONS OF THE FA. THUS...KDVL AND KFAR MAY HAVE THUNDERSTORMS IN THE VICINITY BETWEEN 06Z AND 12Z MONDAY. SURFACE WINDS WILL REMAIN LIGHT AND VARIABLE OVERNIGHT WITH SOUTHEAST WINDS LESS THAN 10 KNOTS DEVELOPING DURING MONDAY MORNING. A CHANCE OF THUNDERSTORMS RETURNS TO THE ENTIRE FA MONDAY AFTERNOON. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && BRAMER
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GRAND FORKS ND 505 AM CDT SUN JUN 20 2010 MNZ001>009-013>017-022>024-027>032-040-NDZ006>008-014>016-024- 026>030-038-039-049-052>054-211200- 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- 505 AM CDT SUN JUN 20 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN NORTH DAKOTA...WEST CENTRAL AND NORTHWEST MINNESOTA. .DAY ONE...TODAY AND TONIGHT ISOLATED THUNDERSTORMS ARE POSSIBLE ACROSS NORTHEAST NORTH DAKOTA TODAY. THUNDERSTORM CHANCES WILL EXPAND TO ALL OF EASTERN NORTH DAKOTA AND A PORTION OF WEST CENTRAL MINNESOTA TONIGHT. A FEW STRONGER STORMS ARE POSSIBLE ALONG THE SOUTH DAKOTA AND NORTH DAKOTA BORDER TONIGHT. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY CHANCES FOR THUNDERSTORMS EXIST MONDAY INTO WEDNESDAY. THERE IS A SLIGHT RISK FOR SEVERE STORMS LATE MONDAY NIGHT FOR AREAS WEST OF THE RED RIVER VALLEY. THERE IS A SLIGHT RISK FOR SEVERE STORMS ON TUESDAY FOR THE ENTIRE REGION. ADDITIONAL THUNDERSTORMS CHANCES EXIST FRIDAY INTO SATURDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED ON TUESDAY.
The Fargo/Grand Forks radar (KMVX), 86 km away, was scanning. The volume nearest the first event began at 07:02 UTC.
1 thunderstorm wind, 1 hail. Local standard time, as filed.
The wind gust was estimated at 60 mph at the intersection of 34th Street and 7th Avenue Northeast in Moorhead with 1/2 mile visibility and torrential rain.
The report was relayed by the media.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Minnesota in 2010Every state in 2010This day in weather historyWarnings in Minnesota, June 2010
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: 227303, 226311.