583
FXUS65 KTFX 250531
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1031 PM MST Mon Nov 24 2025

Aviation Section Updated.

.KEY MESSAGES...

 - Scattered snow showers will continue this afternoon and evening
   along and north of I-90.

 - Gusty winds continue across the region today.

 - Tuesday and Wednesday remains calmer, with light mountain snow
   on Wednesday.

 - Colder and slightly snowier for post-Thanksgiving travel.

&&

.UPDATE...
/Issued 627 PM MST Mon Nov 24 2025/

Slight adjustments were made to the short-term forecast based on
updated model guidance and trending observations. Light snow will
continue over the next few hours and taper off towards midnight.
For now the current Winter Weather Advisories are good and will be
allowed to run their course. Updated model guidance did suggest at
slightly higher amounts of snow being picked up along the higher
elevations of the Little Belts and Bears Paw but not enough to be
concerned about additional impacts beyond what has already been
messaged.

There is a 20% chance patchy fog could linger through the day
tomorrow in northern Hill and Blaine counties but this is hinged
on a lot of moving factors coming together at the right time. If
the clouds clear in the early morning, a thicker layer of fog
develops, and winds remain light through the day there is a chance
the fog could hold on. But the chance is only marginal hence there
is only a 20% confidence in this happening. The more likely
scenario will be fog develops Tuesday night into Wednesday
morning. Overall, widespread significant reductions to visibility
are not expected along Hwy 2 but motorists should be prepared for
sudden changes in visibility if heading out tomorrow.  -thor

&&

.DISCUSSION...
/Issued 627 PM MST Mon Nov 24 2025/

 - Meteorological Overview:

The current shortwave trough is passing through, and will
continue to bring scattered to widespread snow showers for areas
mainly along and north of I-90 through the afternoon. This will
transition to more widespread stratiform light snow this evening
through late tonight. Although snowfall accumulations will remain
light across lower elevations, these snow showers will cause
rapid reductions in visibility. Stronger mid level winds will
keep gusty winds across the region through mostly sunset today.
Central MT will see these stronger winds linger until late
tonight. This low pressure system will push off to the southeast
during the overnight hours, drying out the region. Overnight,
there will be some slight clearing in the clouds. Given recent
snowfall, there is a slight chance for some patchy fog/low stratus
Tuesday morning. Any pavements that are still wet overnight
tonight, will freeze with overnight temperatures dropping into the
20s to teens.

After this system passes, northwest flow aloft settles in behind.
Tuesday looks on track to remain dry with temperatures remaining
near normal. Wednesday, a weak shortwave moves through the region,
bringing another round of precipitation. However, weak forcing
and small amounts of moisture will keep snowfall light over the
mountains with a rain/snow mix across lower elevations.

Heading into the Thanksgiving Holiday time period, a front
lifting north looks to bring some widespread light snow
throughout the day. Models begin to diverge a bit Thanksgiving
onwards. There is still some variations in the timing of
precipitation and amounts Thanksgiving through the weekend.
Ensembles still hint at colder temperatures also moving in this
weekend. There remains uncertainty on how cold it gets based on
this model variation in the evolution of the trough forming along
the West Coast U.S. Main messaging is, expect colder and slightly
snowier conditions this weekend. Expect at least minor winter
impacts to post holiday travel, especially over mountain passes.


 - Forecast Confidence & Scenarios:

Additional Snowfall Today:

Additional snowfall amounts will remain light across lower
elevations and more minor along the remaining mountain passes.
However, this afternoon King`s Hill/Bears Paw and the Eastern
Glacier Park zone could see some moderate banding in snow.
Conditions still look to stay below Winter Storm Warning Criteria
through the evening, but we will continue to monitor for any
heavier snow banding that develops.

Along the Hi-line towards the Canadian border, a more minor
additional accumulations of up to 3" can be expected, so the
Winter Weather Advisory remains in effect until late tonight.

Winds Today:

Probabilities for peak winds haven`t changed too much, and the
current wind forecast seems be be on track this afternoon. The
main area to watch for this evening is southeastern Fergus County.
Hi-res guidance shows and isolated chance for some high winds
down there, but since it`s in a localized area I am not confident
to issue a High Wind Warning down there.


Snow Later This Week:

With variations of the timing and position of the next coming
shortwave on Thanksgiving/Friday, it`s hard to pin point some
details out including snowfall amounts. However, ensembles give a
20-50% chance for two inches of snow across the lower elevations
Thursday/Friday. The Northern Rockies/Eastern Glacier Park region
have the potential to see more minor to moderate snowfall, with
Marias Pass having a 50% chance for 6" of snow. -Wilson


&&

.AVIATION...
25/06Z TAF Period

Snow is expected to diminish across the lower elevations by 25/08Z
with scattered mountain snow showers continuing through 25/12Z
before tapering off. Mountain obscuration will remain a concern
through the first 6 hours of the period. There is a chance for
fog developing overnight where clearing occurs, particularly at
KHVR, but at this time the probabilities are too low to include
it in the TAF.

After 25/12Z, low-level clouds will clear out and give way to mid
to high level clouds through most of the day before cloud cover
starts to increase in the afternoon past 26/00Z with the potential
for some lower ceilings that may reignite some concerns for
mountain obscuration through the remainder of the period.
-thor

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  21  36  26  39 /  70   0  20  20
CTB  13  31  15  33 /  30   0  10  10
HLN  18  33  25  37 /  50   0  40  50
BZN  15  33  22  38 /  20   0  50  70
WYS   5  27  14  31 /  10   0  60  90
DLN  14  33  23  42 /   0   0  20  20
HVR  16  29  11  27 /  90  10   0  10
LWT  15  34  19  34 /  70   0  10  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 11 PM MST this evening for Bears
Paw Mountains and Southern Blaine-Big Belt, Bridger and Castle
Mountains-East Glacier Park Region-Hill County-Little Belt and
Highwood Mountains-Northern Blaine County-Southern Rocky
Mountain Front.

&&

$$
http://www.weather.gov/greatfalls