487
FXUS63 KFGF 021743
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
1243 PM CDT Tue Sep 2 2025

.KEY MESSAGES...

- There is a level 1 out of 5 risk for severe storms this
  afternoon far southeast North Dakota into west- central
  Minnesota. Main hazards include hail to the size of quarters
  and wind gusts to 60 mph.

- Below average temperatures will occur mid to late week, with
  morning frost likely over parts of the region. This includes a
  30% chance for below freezing temperatures in northwest
  Minnesota Thursday morning.

&&

.UPDATE...
Issued at 1242 PM CDT Tue Sep 2 2025

Wind shift to the northwest from the frontal boundary has moved
to a Gwinner to Waskish line, and continues to push southeast.
Some thunderstorm cells have developed out ahead of the front in
Grant county, but so far the main impacts have been lightning.
Still some towering cumulus along a few spots in the front, and
the SPC meso page has some elevated CAPE even a bit behind the
boundary. Will continue to keep an eye on convection as
everything drops south.

UPDATE
Issued at 959 AM CDT Tue Sep 2 2025

Showers and thunderstorms continue to push along the lead
shortwave into Otter Tail and Grant counties, so adjusted POPs
accordingly. Some cumulus starting along the frontal boundary
that is close to going through Fargo. After a bit of a break
should see redevelopment this afternoon and will continue some
messaging for marginal risk for severe. Main question will be if
we get storms along the front before it exits our area, or if
it will all be south and east.

UPDATE
Issued at 655 AM CDT Tue Sep 2 2025

500 mb upper level trough and short wave making its way slowly
east and southeast as 500 mb low is dropping south-southeast
from northern Canada. One last period of showers and storms Park
Rapids to Fergus Falls moving out. But do have one last area
near Ada moving SSE. Then looking for a break until we see where
front ends up later today.

&&

.DISCUSSION...
Issued at 343 AM CDT Tue Sep 2 2025

...Synopsis...

Complex storm pattern from yesterday resulted in a cluster of
t-storms forming late afternoon and evening in south central MB.
These storms developed southeastward into NW MN on the nose of a
zone of 850 mb warm advection that has been ever so slowly
dropping south-southeast thru western MN overnight. Cores big
enough for some pea hail at times but thankfully not strong
enough shear to keep cores growing high enough for larger hail.
Upper level wave also in NW MN and this wave remains quite a bit
stronger it does appear from what global models have indicated.
This upper wave moves out this morning.

...Isolated severe storms possible far south later today....

Focus is upstream cold front. 500 mb low is dropping south-
southeast with 850 mb cold advection still held up north of
Brandon MB. As the current 500 mb trough moves out this will
allow the upper wave and cooler air mass and north wind to drop
south into the area today. Main cold advection waits til the
aftn in NE ND and then this evening in SE ND/MN. Position of the
cold front at time of max heating will determine t-storm
development mid to late aftn. Model consensus from HRRR and
other CAMs as well as GFS/GEM/ECMWF indicate the most likely
scenario (70 pct chance) of the front being just south of the
fcst area from NE SD into MN and max instability in this area
over 2000 j/kg. This thinking region from Milbank, Sisseton,
Watertown east to Benson and Willmar MN would have a bit higher
chance for strong/severe storms late today/evening. Until
frontal timing is more clear, cannot rule out a strong or severe
storm in our far south fcst area there south of Wahpeton to
south of Fergus Falls/Wadena.

Otherwise we will have an upper level short wave quickly moving
on the southwest side of the 500 mb low dropping southeast give
some showers midday/aftn from NW thru central ND. Eastern edge
of shower chances likely to be near Devils Lake, Valley City,
Forman. This is a separate wave from the cold front.

Cold advection and likely stratocu will be overspread the area
tonight into Wednesday. Showers possible in NW MN.

...Frost potential late Wed night/early Thursday...

Center of high pressure will drop from southeast Saskatchewan
thru central ND into eastern SD from Wed into Thursday morning.
But enough sfc ridge north to give western MN a period of near
calm winds and likely clear sky. If that occurs, an area of
temperatures dropping below 36 is likely in a large part of the
forecast area....highest chances (70 pct) in the more typical
colder areas from south of Roseau to Fosston, Bagley, Bemidji,
to Mahnomen and east of Detroit Lakes. This area has a 30 pct
chance of seeing lower than 32 degrees. Also add Langdon area to
this. Elsewhere probs of temps below 36F into the RRV and E ND
is more in the 30-40 pct range with sub freezing temps outside
of NW MN area mentioned less than 5 pct.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1242 PM CDT Tue Sep 2 2025

VFR to MVFR conditions and several sites showing stratus on the
backside of the frontal boundary and even in a few spots out
ahead of the front. Should see a break to VFR conditions for all
sites later this evening, then back down to MVFR for most of our
airports for a period tomorrow morning as cooler air moves down
from the north. Winds northwesterly gusting up to 25 kts this
afternoon and some spots will drop a bit in speed overnight,
then pick up again with gusts above 20 kts tomorrow morning.

&&

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

&&

$$

UPDATE...Riddle/JR
DISCUSSION...Riddle
AVIATION...JR