915 
FXUS63 KFGF 121122
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
622 AM CDT Sat Sep 12 2026

.KEY MESSAGES...

- There is a high chance for soaking rainfall late Sunday night
  into Monday across the region which could impact outdoor 
  activities.

&&

.UPDATE...
Issued at 403 AM CDT Sat Sep 12 2026

Expect a BKN CU deck to develop today with daytime heating in
the northeast half of the fcst area where 850 mb moisture today
will be higher. Northwest winds today 10-20 kts sustained gusts
25 kts. Highs in the 60s. Rain arrives overnight Sunday night
into Monday as it moves in from the southwest. QPF probs from
the NBM and WPC indicate chances for 0.50 inch or more at 70
percent or higher 00z Mon to 00z Tue. With clear sky much of
Sunday night in parts of northwest MN (around Lake of the Woods
and Red Lakes, did follow DLH and lowered lows a few degrees as
some upper 30s in those areas are likely as winds will be calm.

&&

.DISCUSSION...
Issued at 230 PM CDT Fri Sep 11 2026

...Synopsis...

A cold front is pushing through the Northern Plains this afternoon, 
keeping temperatures in the north in the 60s. Meanwhile ahead of the 
front in far southeastern ND into west central MN, temperatures have 
reached the mid 80s, and dew points have climbed into the mid 60s, 
creating a narrow, couple of county wide axis of instability. As the 
cold front propagates through during the late afternoon and evening 
hours, thunderstorms are anticipated to develop, some of which will 
become strong to severe. 

Over the weekend, a large upper low will dig into the Pacific 
Northwest. Tracking eastward by late Sunday into Monday, widespread 
rain is forecasted for the Northern Plains. Behind this system, 
zonal flow will keep temperatures in the 60s most days. Rising 
heights late next week may bring a few 70s back into the forecast. 

...Severe Risk Today...

A cold front pushing eastward will provide the catalyst for 
thunderstorm development late this afternoon into the evening hours. 
Latest satellite imagery shows a developing stratocumulus field
ahead of the front in Grant, Otter Tail and Wadena Counties. 
Capping is forecast to erode between 4 and 5 o'clock. As it 
erodes, the expectation is for storms to develop along the 
front, which should then be situated in the western reaches of 
the current SPC severe weather level 2 out of 5 risk area. 
Storms will have a narrow but rich axis of instability to work 
with, with MLCAPE approaching 3000 J/Kg, and effective shear of 
around 40 knots. Meanwhile, across eastern South Dakota, a 
surface low is propagating eastward/northeastward. In west 
central MN, closer to where this surface low will be located by 
this evening, more low level curvature within hodographs will 
foster the potential for a tornado or two. Further north 
(especially north of US Highway 2), hodographs are straighter, 
keeping the severe risk tied more to a hail and wind threat 
instead of tornado. One big question is how quickly storm mode 
becomes messy. The front should provide strong enough forcing 
for several updrafts to go up at once. If this occurs, the 
window for truly discrete storms will be shorter, leaving the 
potential for significant hail and a tornado or two shorter in 
duration. Activity will cluster and grow upscale as it pushes 
eastward, leaving our FA around 10 PM this evening. 

...Late Weekend into Early Next Week Rainfall...

A large upper low over the Pacific Northwest will propagate eastward 
towards the Northern Plains late Sunday into Monday. Very little 
instability appears in place, therefore severe weather is not 
expected. However, as the low tracks from southwest to northeast 
across the Northern Plains and Canadian Prairies, rainfall will 
overspread the region from west to east Sunday night, lasting into 
Monday. While there remains uncertainty in where the deformation
band and heaviest rainfall will set up, with NBM probabilities 
for a half inch of rain is about 60 percent across the entire 
FA.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 619 AM CDT Sat Sep 12 2026

Northwest winds pickup pretty quickly today with mixed layer up
to around 6000 ft agl where winds of 20-25 kts will mix down.
850 mb moisture and forecast soundings indicate a BKN CU field
today north and east parts of the fcst area. Southern fcst area
will see some CU but more in the way of altocu mid clouds. Winds
diminsh quickly early this evening and become light overnight. 

&&

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

&&

$$

UPDATE...Riddle
DISCUSSION...Rafferty
AVIATION...Riddle