573
FXUS63 KFGF 042346
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
646 PM CDT Sat Oct 4 2025

.KEY MESSAGES...

- There is a level 1 out of 5 risk for severe thunderstorms this
  evening and early overnight across eastern North Dakota and
  parts of northwest Minnesota.

- Rain is expected over most of northeastern North Dakota and
  far northwest Minnesota tonight into Sunday. There is a high
  chance for greater than 1 inch of rainfall across northeast
  North Dakota.

- A period of strong northwest winds arrive late Sunday morning
  through Sunday afternoon, with a 50% chance for wind gusts 45
  mph or greater over parts of the region.

- There is a chance for frost during the morning hours Monday
  through Wednesday over parts of the region.

&&

.UPDATE...
Issued at 646 PM CDT Sat Oct 4 2025

We are in a wait and see approach here this evening in
anticipation of thunderstorm development after sunset.
Thunderstorms are anticipated to develop along the frontal zone
after 9 PM. Otherwise updated grids to reflect current
conditions.

&&

.DISCUSSION...
Issued at 349 PM CDT Sat Oct 4 2025

...Synopsis...

Broad troughing is shifting east, with diffluent SW flow over the
Northern Plains where ridging is beginning to break down. Increased
forcing will support the period of rain tonight and the shift in
pattern and arrival of several fronts is brining seasonal
temperatures back to the region early next week. NW flow should keep
main dry and seasonable temperatures in place through Tuesday night.
The larger scale pattern is a bit more complicated by mid to late
next week as either split-flow or west-southwest zonal flow
redevelops into the plains. Current forecast supports increasing
temperatures and minimal chances for precipitation, though it is a
pattern that could feature lower predictability shortwaves that
carry higher variability. While temperatures do increase above
average, based on NBM probabilities spreads they would still be
relatively mild and not as hot as this last warm up, with the 75th
percentiles in the 70s by next weekend.

...Severe threat tonight...

The initial frontal zone is expected to stall and a LLJ (40-60kt)
develops east of this frontal zone, nosing into northwest MN later
this evening/early overnight. The main corridor of elevated
instability is east of this front, while deep effective shear 30-45kt
will be in place. Corridor of concern for elevated strong/severe
storm development would be where the nose of this jet develops in
proximity to the frontal zone, with CAMs showing the timing or
isolated to scattered thunderstorms after 02Z through about 07Z.
Marginally severe hail (up to 1") would be the main concern, though
I wouldn`t rule out an isolated severe wind gust to 60 mph (lower
level profiles would tend to work against a more organized severe
wind threat).

...Widespread rain tonight into Sunday...

Scattered elevated showers have already been tracking across the
Devils Lake Basin, and as the main 700 MB trough axis shifts into
our CWA tonight, deformation along that axis along with 800-700 MB
frontogenesis will help organized bands or areas of rain that would
track behind the main frontal zone over northeast ND into far
northwest MN. Soaking rain is likely across the Devils Lake Basin,
with much lighter totals farther southeast where rainfall amounts
greater than 0.25" will be more dependent on convective activity.

...Strong winds Sunday...

A secondary cold front moves into the region as the main trough
shifts east, and a period of strong CAA coincides with 4-6MB 6hr
pressure rises (strongest synoptic signal in far southeast ND and
west central MN). Mixing heights aren`t great and without the bigger
push of momentum transfer from the CAA confidence is lower in
advisory wind impacts. Still, NBM shows elevated probabilities (50%+)
for 45 mph+ wind gusts and it is a pattern to monitor in the event a
wind advisory becomes needed.

...Frost potential early next week...

Seasonably cooler air arrives by Sunday night, with the 0C to -2C
850MB isotherms over our northern CWA by Monday morning, reinforced
with similar temperatures as a secondary cold frontal arrives Tuesday
morning due to a shortwave moving through northwest flow. These
temperatures aloft are typical for this time of year and under good
radiational conditions (clear skies and lighter winds) the dry
surface Tds advecting into the region should support the potential
for frost or isolated freeze during the morning hours, particularly
in more traditional cold spots. Confidence is low though on whether
we remain clear or not, as this is the type of pattern than nightly
stratus could develop and impact low temps.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 646 PM CDT Sat Oct 4 2025

Complex set of TAFs over the next 24 hours. To start,
thunderstorms will develop this evening, bringing impacts to
KGFK and KTVF. Further west rain will develop at KDVL. With the
precipitation, ceilings will lower into MVFR, eventually into
IFR. Further south, a low level jet will lead to LLWS at KFAR
and KBJI. As we approach sunrise, northerly winds will begin to
increase, really ramping up through the morning hours with gusts
of over 30 knots at times. Rain will break up and slowly
decrease in coverage from south to north Sunday afternoon, with
ceilings slowly rising by late afternoon back into MVFR or even
VFR to end the TAF period.

&&

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

&&

$$

UPDATE...Rafferty
DISCUSSION...DJR
AVIATION...Rafferty