Multiple showers and a few thunderstorms developed over western and central North Dakota to the north of a slow moving low pressure system over South Dakota. One of these storms produced a landspout tornado near to the northwest of Arnegard in McKenzie County.
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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 BIS wrote it up.
Multiple showers and a few thunderstorms developed over western and central North Dakota to the north of a slow moving low pressure system over South Dakota. One of these storms produced a landspout tornado near to the northwest of Arnegard in McKenzie County. The tornado impacted no structures, thus there was no damage to evaluate. By National Weather Service policy the tornado is rated EF-U (Unknown). In addition, a funnel cloud also developed to the south of Ross in Mountrail County.
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 Bismarck, ND wrote its last area forecast discussion before the first event at Sep 17, 12:38 PM MST, 4 minutes earlier. Its key messages:
Area Forecast Discussion National Weather Service Bismarck ND 238 PM CDT Wed Sep 17 2025 .KEY MESSAGES... - Showers and isolated embedded thunderstorms continue this afternoon over south central and into the far southwest. Isolated showers and thunderstorms are possible west and north central through early this evening. - Showers and isolated thunderstorms remain in the forecast tonight through Friday. The highest rain chances tonight into Thursday are over southern and central portions of the forecast area. Thursday night and Friday the highest rain chances will be along and east of the Highway 83 corridor. - High temperatures will be mainly in the 50s and 60s Thursday and Friday, then warming into the 70s over the weekend. Low temperatures will be in the mid 40s to mid 50s. && .DISCUSSION... Issued at 104 PM CDT Wed Sep 17 2025 Scattered to numerous showers continue over south central ND. Although the thunder has pretty much ended here, an isolated embedded thunderstorm can not be ruled out. over western and into north central ND, we are seeing isolated showers and thunderstorms develop. As mentioned earlier today, there is little if any shear here, but instability is in the 500-1000 J/Kg range with increasing low level lapse rates and wk surface vorticity. The non-supercell tornado parameter continues to tick up. Can not rule out a landspout this afternoon during max heating. Think this threat should subside as heating wanes later this afternoon. For tonight, we did add some patchy fog to western ND, near the western fringes of the mid to high level cloud shield, otherwise expect increasing chances for showers and possibly a few thunderstorms later this evening and through much of the day Thursday. A couple of mid-upper level circulations (eastern MT and central SD) are responsible for the precipitation chances as they linger over the area through this evening before converging over southern ND/northern SD late tonight. This will keep the threat for showers and a few thunderstorms in the forecast tonight, Thursday and Thursday night as the mid-upper level circulation makes its way slowly east. There is another, weaker upper level system that moves through the area this weekend that may keep at least a small chance of showers and thunderstorms in the forecast (although current NBM pops are pretty much non- existent Saturday night through Sunday night). Then another upper level system looks to move into the northern/central Plains early next week. There is a lot of uncertainty in the timing/placement and the strength of the systems this weekend and especially early next week. However, there is some general agreement in at least a brief warm and dry period as we head into the middle portions of next week. This is also supported in the latest 6-10 day CPC outlook which is also favoring a warm and dry period over much of the Northern Plains during that timeframe (Sept 23-27). && .AVIATION /12Z TAFS THROUGH 12Z THURSDAY/... Issued at 1153 AM CDT Wed Sep 17 2025 Showers and isolated thunderstorms remain over south central ND. Isolated showers and thunderstorms are possible this afternoon across the remainder of western and central ND as well, although besides the current activity around KBIS, will not include a mention of thunder at this time. Late tonight into Thursday will bring another round of showers, with a low potential for thunder. Expect widespread MVFR-IFR visibilities and ceilings in occasional rain and areas of fog continuing through Thursday morning. Expect an east to northeast surface flow of 5 to 15 knots through the forecast period. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && DISCUSSION...Telken AVIATION...Telken
Hazardous Weather Outlook National Weather Service Bismarck ND 238 PM CDT Wed Sep 17 2025 NDZ001>005-009>013-017>023-025-031>037-040>048-050-051-181945- Divide-Burke-Renville-Bottineau-Rolette-Williams-Mountrail-Ward- McHenry-Pierce-McKenzie-Dunn-Mercer-Oliver-McLean-Sheridan-Wells- Foster-Golden Valley-Billings-Stark-Morton-Burleigh-Kidder- Stutsman-Slope-Hettinger-Grant-Bowman-Adams-Sioux-Emmons-Logan- La Moure-McIntosh-Dickey- 238 PM CDT Wed Sep 17 2025 /138 PM MDT Wed Sep 17 2025/ This Hazardous Weather Outlook is for portions of north central North Dakota, northwest North Dakota, south central North Dakota, southeast North Dakota, and southwest North Dakota. .DAY ONE...This Afternoon and Tonight Isolated thunderstorms are possible this afternoon and tonight. Severe weather is not expected. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday The probability for widespread hazardous weather is low. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed.
The Minot AFB radar (KMBX), 203 km away, was scanning. The volume nearest the first event began at 19:44 UTC.
1 tornado, 1 funnel cloud. Local standard time, as filed.
The tornado touched down in an open field northwest of Arnegard and moved south-southeast. The tornado impacted no structures, thus there was no damage to evaluate. By National Weather Service policy the tornado is rated EF-U (Unknown).
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in North Dakota in 2025Every state in 2025This day in weather historyThe tornado archive for North Dakota, 2025Warnings in North Dakota, September 2025
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: 1295050, 1295049.