After reports of over 3 inches of rain fell, water began to pool in urban areas in Cass and Clay counties. Numerous reports of flooding came in after an areal flood advisory was issued.
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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.
After reports of over 3 inches of rain fell, water began to pool in urban areas in Cass and Clay counties. Numerous reports of flooding came in after an areal flood advisory was issued.
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 5, 6:03 PM CST, 44 minutes earlier.
Area Forecast Discussion National Weather Service Grand Forks ND 703 PM CDT Sat Aug 5 2023 .UPDATE... Issued at 659 PM CDT Sat Aug 5 2023 Upper low continues to move east-southeast this evening. Showers and embedded thunderstorms are forming, generally in waves, in areas to the east of the Red River, with more stratiform activity to the west. Some of the updrafts have been strong enough to produce funnel clouds as low-level vorticity is rather high. This threat will diminish through the evening. && .SHORT TERM...(This evening through Sunday night) Issued at 341 PM CDT Sat Aug 5 2023 -Rain showers with embedded (scattered) thunderstorms are on track to overspread southeast ND and west central MN through the evening hours/overnight transitioning southeast through Sunday. Lightning will be the main threat, and severe thunderstorms are not anticipated. A few stronger storms capable of small hail and gusts to 40 mph will still be possible. -Localized heavy rain may lead to excessive runoff if rates are high enough (3"+/hr), particularly in locations near the SD border where earlier thunderstorm activity occurs. The probability for higher rates is low in all by our far south (south of I-94), with probabilities shifting towards SD/southern MN for 2"+ totals. The main mid level circulation is deepening over central SD in line with the southerly track that had been favored on ensemble/forecast trends in the last 24hr. As a result the strongest signal for broad heavier rain has shifted south. We are seeing broad areas of moderate rainfall with embedded thunderstorms filling in the northern side of this circulation along the warm conveyor belt and eventually this should move into the I-94/US10 corridor early this evening. Elevated instability in the RAP is 1000+ J/KG but skinnier profiles are favored and cloud cover would limit surface based convection. As a result even the strongest updrafts will mainly favor heavy rain/smaller hail and max gusts to 40 mph. Still, with at least some potential for training within these heavier rain pockets there is potential for 1-3"/hr rates. Over dry soils we would likely need 4-5"/hr rates for flash flooding, but preconditioned locations could support excessive runoff if 3"+ rainfall fell over 6hr (mainly near the SD border). Additional storms are forming near the cold front as an inverted trough is beginning to form ahead of the norther wave/mid level jet in Canada. The interaction of these features is still highlighted by CAMs to resulting in organized deformation in our east-southeast late this evening into the overnight/early morning hours with broad light to moderate rainfall. HREF probs show 90%+ probs for 0.01" per hour during those periods while blended ensemble 12hr probs for 0.1"+ are 60-80%. The probability for 0.5" and 1.0"+ 6hr probs drops off quickly (main to the south of I-94) and for those values thunderstorm activity would likely need to occur farther north). THe entire deformation area of rain should decrease in intensity and transition southeast through Sunday morning, with dry conditions arriving by midday based on current timing/consensus. .LONG TERM...(Monday through Saturday) Issued at 341 PM CDT Sat Aug 5 2023 -The pattern will support low probabilities for showers or thunderstorms, with the probability for hazardous weather low through the long term periods. -Temperatures will tend to remain near seasonal normals early in the week, with below average temperatures (by 5-10F) favored late next week into next weekend. Large scale mid/upper level pattern will tend to be dominated by relatively flat NW zonal flow in our region as a result of broad ridging in the southwest US and a more elongated Hudson Bay low in Canada. There is variance in the strength and exact position of those upper level features, but the main impact on the pattern locally between the various clusters is on the timing/track of progressive weak mid level shortwaves. Due to the flow and limited southerly return before each cold front (and tendency for moisture return to be from drier parts of Canada) the potential for wetting precipitation (0.1") and instability will be low with each of these waves and associated fropas. As a result there isn't a signal for severe potential in NBM CWASP or GEFS based machine learning from CSU. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 634 PM CDT Sat Aug 5 2023 MVFR conditions are possible tonight as showers and embedded thunderstorms move across the area. An upper low will pass to our south overnight and into Sunday morning, which will gradually shift the winds more out of the north. As this happens, showers will be winding down in coverage, with slow improvements in ceilings. Visibility is expected to remain 5SM or higher, especially outside of heavier shower activity. VFR conditions develop by mid-morning Sunday. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && UPDATE...Lynch SHORT TERM...DJR LONG TERM...DJR AVIATION...Lynch
Hazardous Weather Outlook National Weather Service Grand Forks ND 331 PM CDT Sat Aug 5 2023 MNZ001>003-006-008-009-013>017-022>024-027>032-040-NDZ027>030-038- 039-049-052-053-062045- West Polk-Norman-Clay-Lake Of The Woods-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- Grand Forks-Griggs-Steele-Traill-Barnes-Cass-Ransom-Sargent- Richland- 331 PM CDT Sat Aug 5 2023 This hazardous weather outlook is for portions of eastern North Dakota, west central and northwest Minnesota. .DAY ONE...This Afternoon and Tonight Scattered showers and thunderstorms are expected across the region beginning this morning and lasting through Sunday. The main hazard will be lightning and areas of locally heavy rainfall. .DAYS TWO THROUGH SEVEN...Sunday through Friday Showers and storms will diminish from north to south through Sunday. The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation is not anticipated. MNZ004-005-007-NDZ006>008-014>016-024-026-054-062045- Kittson-Roseau-West Marshall-Towner-Cavalier-Pembina-Benson- Ramsey-Eastern Walsh-Eddy-Nelson-Western Walsh- 331 PM CDT Sat Aug 5 2023 This hazardous weather outlook is for portions of eastern North Dakota and northwest Minnesota. .DAY ONE...This Afternoon and Tonight The probability for widespread hazardous weather is low. .DAYS TWO THROUGH SEVEN...Sunday through Friday The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation is not anticipated.
Preliminary Local Storm Report
National Weather Service Grand Forks ND
647 PM CDT Sat Aug 5 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0600 PM Rain 1 SE West Fargo 46.86N 96.89W
08/05/2023 E1.80 inch Cass ND Public
&&
TTPreliminary Local Storm Report
National Weather Service Grand Forks ND
648 PM CDT Sat Aug 5 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0600 PM Rain Horace 46.76N 96.91W
08/05/2023 M2.35 inch Cass ND Public
&&
TTPreliminary Local Storm Report
National Weather Service Grand Forks ND
652 PM CDT Sat Aug 5 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0615 PM Rain 1 S West Fargo 46.86N 96.90W
08/05/2023 M2.78 inch Cass ND Public
&&
TTSpecial Weather Statement National Weather Service Grand Forks ND 656 PM CDT Sat Aug 5 2023 MNZ003-NDZ038-039-060600- Clay-Barnes-Cass- Including the cities of Moorhead, Valley City, and Fargo 656 PM CDT Sat Aug 5 2023 ...FUNNEL CLOUDS POSSIBLE ACROSS SE NORTH DAKOTA AND PORTIONS OF WEST CENTRAL MINNESOTA... Showers and thunderstorms have developed across portions of eastern North Dakota and west central Minnesota. Conditions are favorable for funnel clouds with thunderstorms that develop. These types of funnel clouds are usually short lived, however, they can and occasionally do touch the ground and cause minor damage. Because of this possibility, If you see one of these funnel clouds approaching the ground, take cover immediately.
Preliminary Local Storm Report
National Weather Service Grand Forks ND
726 PM CDT Sat Aug 5 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0700 PM Rain 2 WSW Brampton 45.98N 97.82W
08/05/2023 M4.04 inch Sargent ND Mesonet
NDAWN report.
&&
TTSpecial Weather Statement National Weather Service Grand Forks ND 732 PM CDT Sat Aug 5 2023 MNZ027-028-060115- West Becker MN-East Becker MN- 732 PM CDT Sat Aug 5 2023 ...A strong thunderstorm will impact portions of central Becker County through 815 PM CDT... At 732 PM CDT, Doppler radar was tracking a strong thunderstorm near Rochert, or 10 miles east of Detroit Lakes, moving northwest at 10 mph. HAZARD...Penny size hail. SOURCE...Radar indicated. IMPACT...Minor damage to outdoor objects is possible. Locations impacted include... Height Of Land Lake and Rochert. PRECAUTIONARY/PREPAREDNESS ACTIONS... If outdoors, consider seeking shelter inside a building. && LAT...LON 4683 9553 4677 9563 4690 9583 4701 9562 TIME...MOT...LOC 0032Z 139DEG 9KT 4684 9563 MAX HAIL SIZE...0.75 IN MAX WIND GUST...<30 MPH Lynch
The Fargo/Grand Forks radar (KMVX), 86 km away, was scanning. The volume nearest the first event began at 00:45 UTC.
1 flash flood. Local standard time, as filed.
Public reports stranded vehicles in Moorhead due to flooded roadways.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Minnesota in 2023Every state in 2023This day in weather historyWarnings in Minnesota, August 2023
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: 1133045.