Flash Flood Warning 3, NWS Grand Forks, ND

857 
WGUS73 KFGF 070321 RRA
FFSFGF

Flash Flood Statement
National Weather Service Grand Forks ND
1021 PM CDT Sun Sep 6 2026

MNC111-070500-
/O.CON.KFGF.FF.W.0003.000000T0000Z-260907T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Otter Tail MN-
1021 PM CDT Sun Sep 6 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL MIDNIGHT CDT TONIGHT
FOR CENTRAL OTTER TAIL COUNTY...

At 1021 PM CDT, Pictures shared via social media showed flooding
mainly in Perham and was corraborated by law enforcement. Between 4
and 7 inches of rain have fallen. Flooding impacts will continue, but
no additional rainfall is expected. Flash flooding is already
occurring.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Law enforcement reported.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

Some locations that will experience flash flooding include...
  Perham, Ottertail Lake, Ottertail, Star Lake, Deer Creek, Dent,
  Richville, Amor and Glendalough.

This includes the following streams and drainages...
  Finn Creek, Toad River, Otter Tail River, Leaf River and Willow
  Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

Be aware of your surroundings and do not drive on flooded roads.

Please report observed flooding to local emergency services or law
enforcement and request they pass this information to the National
Weather Service when you can do so safely.

&&

LAT...LON 4639 9528 4669 9556 4651 9586 4631 9563

FLASH FLOOD...OBSERVED

$$

Thomas

775 
WGUS73 KFGF 070453
FFSFGF

Flash Flood Statement
National Weather Service Grand Forks ND
1153 PM CDT Sun Sep 6 2026

MNC111-070503-
/O.EXP.KFGF.FF.W.0003.000000T0000Z-260907T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Otter Tail MN-
1153 PM CDT Sun Sep 6 2026

...FLASH FLOOD WARNING WILL EXPIRE AT MIDNIGHT CDT TONIGHT FOR
CENTRAL OTTER TAIL COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed remaining road closures.

&&

LAT...LON 4639 9528 4669 9556 4651 9586 4631 9563

$$

Thomas

Area Forecast Discussion
National Weather Service Grand Forks ND
229 PM CDT Sun Sep 6 2026

.KEY MESSAGES...

- There is a level 2 out of 5 risk for severe storms this
  afternoon and evening in portions of the Devils Lake and
  Sheyenne Basins, mainly for hail to ping pong ball sized. A
  level 1 out of 5 risk for the rest of eastern ND and western
  MN.

- Another round of thunderstorms expected Monday, with a level 1
  out of 5 risk for the entire forecast area. The main impacts
  for any storms that become severe will be ping pong ball sized
  hail and winds to 60 mph.

&&

.DISCUSSION...
Issued at 229 PM CDT Sun Sep 6 2026

...Synopsis...

Several weak shortwaves under the main upper ridge currently
bringing some thunderstorms to central ND and eastern SD.
The main surface low and inverted trough is still over the
western Dakotas, and should begin to move eastward tomorrow as
the flow turns southwesterly and a lead shortwave moves out. The
main upper trough starts to move into Saskatchewan and Manitoba
Monday night, pushing the surface trough and associated cold
front east into the Red River Valley by early Tuesday. West to
northwest surface winds will pick up Tuesday and Wednesday
behind the surface front with decent cold air advection and
pressure gradient, possibly meeting advisory criteria. Near
zonal flow sets up late week and into next weekend, although a
cluster of 34 percent of ensemble members tries to dig a trough
into the Northern Plains. There is a signal in the ECMWF EFI for
a break in the above normal temperatures by next weekend.

...Severe chances this afternoon and evening...

Water vapor loop has the main shortwaves to our south or west,
but there is a small vort currently moving through central ND
that could provide support for more convection as it moves into
our forecast area. ML CAPE is around 3000 J/kg, and while deep
layer shear is not super strong it is around 30 to 35 kts which
should be enough to keep some updrafts going. The low level
lapse rates are not too impressive given the stratus we have
seen much of the day, but there is a decent amount of
instability thanks to dew points in the 70s and temps in the
80s. CAMs continue to be very unreliable and enough ensemble
members of the HREF were showing good probability of updraft
helicity tracks over the southern Red River Valley this morning,
which have not developed. Some of the machine learning runs show
some low to moderate chances for severe impacts, while other
runs do not. Can't completely rule out more convection
developing as the central ND vort moves east, but uncertainty is
high as to what actually develops. If severe storms do develop,
the main threat will be large hail.

...Marginal risk for severe Monday...

The ridge axis shifts east tomorrow and the flow aloft becomes
southwesterly. Deep layer shear will be increasing up into the
40 to 50 kt range by tomorrow afternoon. But the instability
becomes more uncertain. Some of the ensemble members don't have
any surface based CAPE at all, but enough do that the mean CAPE
into eastern ND is around 1500 J/kg. Much will depend on what
exactly happens this evening and into the overnight. HREF and
REFS updraft helicity probabilities have some chance, but not
super impressive. At this point with all the unknowns the level
1 risk seems reasonable.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1243 PM CDT Sun Sep 6 2026

MVFR to IFR ceilings at many of the TAF sites, but the MN side
is starting to mix out and the other airports could see at least
the lower stratus decreasing in coverage in the next few hours.
Convection will come in from the west later this afternoon and
evening, so kept prob30 groups going as there is still a lot of
uncertainty as to exactly when and where. Some MVFR or even IFR
ceilings possible behind the storms later tonight and into
tomorrow. Winds will remain southeasterly except near
thunderstorms, and some gusts up to 20 kts will be possible late
in the period.

&&

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

&&

DISCUSSION...JR
AVIATION...JR

Hazardous Weather Outlook
National Weather Service Grand Forks ND
447 AM CDT Sun Sep 6 2026

MNZ001>005-007-008-013>016-022-023-027>031-040-NDZ006>008-014>016-
024-026>030-038-039-049-052>054-071000-
West Polk-Norman-Clay-Kittson-Roseau-West Marshall-East Marshall-
Pennington-Red Lake-East Polk-North Clearwater-Mahnomen-
South Clearwater-West Becker-East Becker-Wilkin-West Otter Tail-
East Otter Tail-Grant-Towner-Cavalier-Pembina-Benson-Ramsey-
Eastern Walsh-Eddy-Nelson-Grand Forks-Griggs-Steele-Traill-Barnes-
Cass-Ransom-Sargent-Richland-Western Walsh-
447 AM CDT Sun Sep 6 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 1 out of 5 risk for severe thunderstorms this
afternoon and evening across much of eastern North Dakota,
northwest, Minnesota, and west central Minnesota. Hazards could
include large hail and damaging wind gusts. A tornado cannot be
ruled out in southeast North Dakota, west central Minnesota, and
the southern Red River Valley.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

There is a level 1 out of 5 risk for severe thunderstorms Monday
afternoon and evening. Hazards could include large hail, damaging
wind gusts, and possibly an isolated tornado.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be required today.

MNZ006-009-017-024-032-071000-
Lake Of The Woods-North Beltrami-South Beltrami-Hubbard-Wadena-
447 AM CDT Sun Sep 6 2026

This hazardous weather outlook is for portions of west central
and northwest Minnesota.

.DAY ONE...Today and Tonight

Isolated strong storms are possible this afternoon and evening,
with hail and gusty winds being the primary hazards.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

There is a level 1 out of 5 risk for severe thunderstorms Monday
afternoon and evening. Hazards could include large hail, damaging
wind gusts, and possibly an isolated tornado.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be required today.

Preliminary Local Storm Report
National Weather Service Grand Forks ND
538 PM CDT Sun Sep 6 2026

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

0526 PM     Tstm Wnd Gst     1 NE Northwood          47.74N 97.56W
09/06/2026  M62 MPH          Grand Forks        ND   Trained Spotter

            62 mph gust reading on handheld kestrel east
            of Northwood. 35-40mph sustained.

&&

TT

Preliminary Local Storm Report
National Weather Service Grand Forks ND
539 PM CDT Sun Sep 6 2026

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

0512 PM     Tstm Wnd Gst     7 W Northwood           47.72N 97.72W
09/06/2026  M53 MPH          Grand Forks        ND   Public

            Davis personal weather station.

&&

TT