Alert archive / Minnesota / Severe Thunderstorm Warnings in 2026

Severe Thunderstorm Warning 192, NWS Grand Forks, ND

September 3, 2026Mahnomen County, Minnesota

NWS Grand Forks, ND issued this severe thunderstorm warning at Sep 3, 2026, 10:00 PM CDT for Mahnomen County, Minnesota. It was in force for 28 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Sep 3, 2026, 10:00 PM CDT (03:00 UTC)
Expired
Sep 3, 2026, 10:28 PM CDT
In force
28 min
Issued by
NWS Grand Forks, ND
Area
Storm-based polygon
Hail
1.0 in
Wind
50.0 mph

County Mahnomen County, MN

The radar

The Fargo/Grand Forks radar (KMVX), 116 km from the middle of the area, began a volume at 03:03 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Sep 3, 12:12 PM CDTSevere Thunderstorm WatchSPC11 hr

The nearest sounding before it

Minneapolis, MN (KMPX), launched 00:00Z, 3.0 hours before the alert went out and 324 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Minneapolis, MN at 00:00Z on 2026-09-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2812 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Minneapolis, MN at 00:00Z on 2026-09-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 116 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
2812 J/kg
Mixed-layer CIN
-98 J/kg
Mixed-layer LCL
1076 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
116 m²/s²
0-3 km storm-relative helicity
233 m²/s²
Significant tornado parameter
2.0
Supercell composite
8.8

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, 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 this severe thunderstorm warning went out at Sep 3, 6:20 PM CDT, 3 hours 40 minutes earlier. Its key messages:

  • Level 2 out of 5 risk for severe storms continues through early evening.
  • Additional chances for strong to severe thunderstorms exist Saturday and Sunday.
Area forecast discussion, Sep 3, 6:20 PM CDT, 3 hours 40 minutes before
Area Forecast Discussion
National Weather Service Grand Forks ND
Issued by National Weather Service Rapid City SD
620 PM CDT Thu Sep 3 2026

.KEY MESSAGES...

- Level 2 out of 5 risk for severe storms continues through
  early evening.

- Additional chances for strong to severe thunderstorms exist
  Saturday and Sunday.

&&

.DISCUSSION...
Issued at 241 PM CDT Thu Sep 3 2026

...Synopsis...

Southwesterly flow aloft with a lead shortwave lifting from near
the MT border through the Northern Plains. Storms have been
ongoing in northeastern ND into far northwestern MN, and will
continue to push eastward along the warm front/theta-e gradient
that is between the Highway 2 and Highway 200 corridors. The
shortwave will move northeast overnight, and upper ridging will
begin to amplify over the Plains tomorrow. Upper ridging
continues to build over the region into the weekend, with
several weak embedded shortwaves possible. By early next week,
the upper ridge starts to flatten and move east, with continued
active weather under southwesterly flow aloft. A trough moving
through Manitoba and Ontario on Wednesday will push east
Thursday and leave the region in northwesterly flow.

...Convective trends and severe threat this evening...

Complex of thunderstorms in northeastern ND is currently
crossing into northwestern MN. Most of the instability seems to
be elevated, with SPC mesoanalysis still showing a good amount
of CIN on surface based and mixed layer CAPE, but there has been
enough mixing to get a few 60 and even 70 mph reports to the
surface. The shear at 0-3km is favorable for brief tornado spin
ups along some kinks in the line, but would need to get some
better low level CAPE developing before that could happen. Think
that this will be the case eventually with sunshine over the
southern forecast area. Even if we don't get a fully mixed
boundary layer, with continued lift, good deep layer shear
around 50 kts, and dew points in the upper 60s to near 70
feeding into the complex, expect some re-intensification of
storms and a continued threat of large hail and winds up to 70
mph.

...Storm chances Saturday and Sunday...

After a break tomorrow, additional weak embedded shortwaves
under the building ridge will bring some rounds of showers and
thunderstorms. Temperatures will be well above average for early
September and there should be good instability to work with. The
deep layer shear is not as strong this weekend as today, but at
30 kts could still be adequate for strong to severe storms.
Machine learning has some low probabilities for severe impacts
for the weekend time period, mainly in the 5 to 15 percent
range. Still some uncertainty, but will have to watch for some
active convective days this holiday weekend.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 610 PM CDT Thu Sep 3 2026

Isolated/scattered shra/TS will slide through the forecast area
this evening with local IFR conditions, but precipitation should
stay north of KFAR and wane by 04/04z. Rather widespread
MVFR/IFR CIGS will slide south into the region after 04/04z,
likely reaching all terminals for at least a few hours into
Friday morning. Improvement will occur by 04/18z from KDVL-KFAR,
but MVFR/local IFR conditions should linger for KGFK/KBJI/KTVF
into the early afternoon. Have left out visibility restrictions
for now, but there is a signal for some fog. Later updates can
address.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.

&&

DISCUSSION...JR
AVIATION...NWS UNR
Hazardous weather outlook, Sep 3, 5:45 AM CDT, 16 hours 15 minutes before
Hazardous Weather Outlook
National Weather Service Grand Forks ND
545 AM CDT Thu Sep 3 2026

MNZ001>009-013>017-022>024-027>032-040-NDZ006>008-014>016-024-
026>030-038-039-049-052>054-041045-
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-Eddy-Nelson-Grand Forks-
Griggs-Steele-Traill-Barnes-Cass-Ransom-Sargent-Richland-
Western Walsh-
545 AM CDT Thu Sep 3 2026

This hazardous weather outlook is for portions of eastern North
Dakota, west central and northwest Minnesota.

.DAY ONE...Today and Tonight

There is a level 2 out of 5 risk for severe thunderstorms this
afternoon and evening for much of eastern North Dakota and
northwest and west central Minnesota. The main hazards will be
large hail to golf balls, 60 mph wind gusts. There is a chance for
a isolated tornado.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be required today.

In the hours before

Local storm report, Sep 3, 7:38 PM CDT, 2 hours 22 minutes before
Preliminary Local Storm Report
National Weather Service Grand Forks ND
738 PM CDT Thu Sep 3 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0735 PM     Hail             Fergus Falls            46.28N 96.07W
09/03/2026  M1.00 Inch       Otter Tail         MN   Trained Spotter

&&
Local storm report, Sep 3, 7:56 PM CDT, 2 hours 4 minutes before
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Local storm report, Sep 3, 8:22 PM CDT, 1 hour 38 minutes before
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Local storm report, Sep 3, 9:17 PM CDT, 43 minutes before
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Local storm report, Sep 3, 9:18 PM CDT, 42 minutes before
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Local storm report, Sep 3, 9:58 PM CDT, 2 minutes before
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The office that day

Everything else NWS Grand Forks, ND issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 3, 7:11 PM CDTSevere Thunderstorm Warning Considerable damage threatFGFOtter Tail, Wilkin64 min
Sep 3, 7:19 PM CDTSevere Thunderstorm Warning Considerable damage threatFGFMarshall, Pennington, Polk, Red Lake56 min
Sep 3, 7:38 PM CDTTornado WarningFGFGrant, Otter Tail52 min
Sep 3, 8:09 PM CDTSevere Thunderstorm WarningFGFBeltrami, Clearwater, Marshall, Pennington, Red Lake66 min
Sep 3, 8:12 PM CDTSevere Thunderstorm WarningFGFClearwater, Polk, Red Lake63 min
Sep 3, 8:16 PM CDTSevere Thunderstorm Warning Considerable damage threatFGFOtter Tail59 min
Sep 3, 9:10 PM CDTSevere Thunderstorm Warning Considerable damage threatFGFClearwater, Mahnomen, Polk65 min
Sep 3, 10:03 PM CDTSevere Thunderstorm WarningFGFHubbard57 min
Sep 4, 3:51 AM CDTDense Fog AdvisoryFGFKittson, Marshall, Roseau6 hr

Nearby

Severe Thunderstorm Warnings in Minnesota, 2026Every severe thunderstorm warning in 2026

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.