036 
FXUS63 KFGF 251246
AFDFGF

Area Forecast Discussion
National Weather Service Grand Forks ND
746 AM CDT Sat Oct 25 2025

.KEY MESSAGES...

- Areas of dense fog west of the Red River Valley in eastern
  North Dakota through this morning.

- Warmer then average through the weekend with gusty winds on 
 Sunday.

- High confidence in a wetting rain early next week.

&&

.UPDATE...
Issued at 730 AM CDT Sat Oct 25 2025

Dense fog continues to slowly work its way northward into
far southeast ND, as driven by moisture advection. Fog will
continue to migrate northward deeper into eastern ND just west
of the Red River Valley.

Uncertainty exists in cloud cover today, with low stratus 
capable of lingering throughout the day. Should this occur, 
cooler daytime temperatures will ensue staying within the 50s.

&&

.DISCUSSION...
Issued at 338 AM CDT Sat Oct 25 2025

...Synopsis...

Upper ridging aloft this weekend will promote above average
temperatures today and Sunday. Tightening pressure gradient and
increased low level winds will bring gusty winds today, tonight,
and Sunday. This weekend's upper ridging will give way to
troughing aloft early next week. Sufficient forcing and moisture
lends high confidence in at least a wetting rainfall within
portions of eastern Dakotas into Minnesota between Monday and
Tuesday.

...Dense fog this morning...

Early this morning, satellite is showing fog and very low
stratus forming/advecting within eastern South Dakota,
with dense fog noted along and near the escarpment west of 
James River Valley. This is due to low level moisture advection
into relatively cool air mass over the Northern Plains. High
resolution guidance like HRRR/RAP/HREF all depict this scenario,
with eventual overspreading of dense fog into eastern ND, mainly
west of the Red River Valley. There is some potential in dense
fog hugging along the western portion of the Red River Valley
itself, however, there is lower confidence in this. Guidance
advects this fog into the region by sunrise, lingering through 
the morning, and perhaps lasting into the afternoon hours. As is
typical for this time of year, fog can linger a bit longer than
what guidance would indicate. One thing that may help cease fog
by the afternoon will be increasing winds, perhaps helping mix
out or at least lift fog into stratus. While there isn't a 
Dense Fog Advisory out yet, there will likely be a need for one 
today.

...Above average temperatures and gusty winds this weekend...

Upper ridging over the region today and Sunday and long southerly
fetch will promote warming temperatures aloft to advect into 
the region. This will bring above average temperatures, although
how much above will depend on cloud cover. Temperatures will
confidently reach into the 50s, with temperatures into the 60s
still possible (more likely if skies remain clear). 

Tightening surface pressure gradient as well as increasing winds
aloft over the Dakotas will promote gusty south to southeast winds
in excess of 30 mph today through Sunday. The south-southeast 
direction of winds tonight as well as low level jet around 45 
mph may promote gusty winds through the overnight hours Saturday
within the Red River Valley.

While pressure gradient alone will help drive windy conditions,
there is some uncertainty in how high wind gusts will reach. 
This is due to uncertainty in mixing potential into the stronger 
wind just above the surface, particularly on Sunday. Increasing 
cloud cover ahead of an approaching trough and associated 
moisture may temper mixing potential. 

There is a 30% chance winds will reach into the 45-55 mph range
Saturday overnight into Sunday within eastern North Dakota and
the Red River Valley.

...Wetting rainfall early next week...

This weekend's upper ridge will continue to build north and east
into Canada, to a point where it cuts itself off as strong
anticyclone near the southern Hudson Bay region. While this 
occurs, upper troughing on the cyclonic side of upper jet 
nosing into the Pacific Northwest will induce upper troughing 
into the central CONUS along with Pacific-sourced moisture. 

The strong upper anticyclone will promote a block-type pattern,
helping split energy associated with the upper trough into 
interior Canada as well as into the Central Mississippi Valley 
by Tuesday. During this transition, sufficient moisture and 
forcing will produce rainfall within the Northern Plains Monday 
and Tuesday. While this splitting of energy will mitigate 
overall strength of synoptic forcing, relatively rich moisture 
content along with mesoscale forcing will drive rainfall in 
excess of 0.25 inches, potentially as high as 1.5 inches.

Strong and persistent convergence within the central and 
eastern Dakotas will help focus precipitation near a surface 
north-to-south oriented surface trough. This convergence 
coupled with divergence aloft will also help promote fgen in the
low and mid levels. Guidance also hints as some
conditional/slantwise instability feeding into these fgen
circulations. These mesoscale forcing mechanisms lower 
confidence in how widespread soaking rainfall amounts in excess 
of 0.5 inches will be. Should this type of mesoscale forcing 
dominate, rainfall may be locally enhanced while also spatially 
smaller near the surface trough. This would also make higher end
amounts in the 1.0-1.5 inch range more likely, but again in a 
spatially smaller area. As of now, ensemble guidance keeps the 
chance for these higher end amounts (30%) within central to 
eastern North Dakota Monday through Tuesday.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 730 AM CDT Sat Oct 25 2025

Aviation impacts are forecast within the TAF period due to IFR
ceilings and gusty winds. While there will be LIFR/VLIFR 
ceilings and dense fog in the region, they are not currently
forecast to impact TAF sites. Overall confidence in the
ceiling/sky coverage forecast is low, particularly after 18Z.

Low stratus will move into the region from the south today and
tonight. KDVL is currently forecast to dip into MVFR ceilings
around 06Z tonight. There is also a 40% chance KDVL has fog
impact that site between 15Z-18Z. And while most sites are 
forecast to have ceilings stay VFR, confidence in this is low 
after 18Z. There is a 20% chance IFR to MVFR ceilings impact 
these other sites.

Winds will be out of the south-southeast today and tonight
increasing around 15-25kt after 16Z. Winds will remain elevated
through the overnight hours, and even increase after 03Z at
sites like KFAR, possibly occurring at KGFK and KTVF as well.
Low level wind shear may also be present between 03Z-13Z as
well. Sunday is forecast to be windy as well.

&&

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

&&

$$

UPDATE...CJ
DISCUSSION...CJ
AVIATION...CJ