081
FXUS65 KTFX 231801
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1101 AM MST Sun Nov 23 2025

Aviation Section Updated.

.KEY MESSAGES...

 - Above normal temperatures and gusty conditions continue today.

 - Windier conditions are expected on Monday as a cold front
   moves across the Northern Rockies, with increasing
   precipitation chances and mountain snow.

 - Much colder conditions are expected for next weekend.

&&

.DISCUSSION...
/Issued 459 AM MST Sun Nov 23 2025/

 - Meteorological Overview:

Zonal flow over the Northern Rockies will yield one final day of
well above normal temperatures across Southwest through North
Central Montana, along with gusty southwest to west surface winds.
Precipitation chances will begin to increase through the day today
along the Continental Divide as Pacific moisture is advected northeast
ahead of a shortwave sliding towards the Pacific Northwest. This
shortwave will then slide east and over the Northern Rockies on
Monday, with precipitation overspreading all of Southwest through
North Central Montana. Precipitation through this timeframe will be
heaviest over the mountains, and to the northwest of the surface low
(i.e. Hi-Line), which is currently prog`d to track across Central
Montana. A cold front diving southeast from Alberta and across
Montana on Monday will lead to falling temperatures, with most
locations across North Central and Central Montana seeing their
highs occurring in the morning hours while Southwest Montana sees a
more traditional timeframe for highs.

Northwest flow in wake of the shortwave on Monday will help to
maintain daily chances for precipitation through the remainder of the
work week, along with near normal temperatures. By Friday night a
potent longwave trough will begin to dig south from Canada and over
the Northern Rockies, with much colder air arriving to the Northern
Rockies as an Arctic front pushes south from Canada. - Moldan

 - Forecast Confidence & Scenarios:

Strong Winds on Monday...

NBM4.3 probabilities for wind gusts in excess of 48kts continue to
remain relatively low, generally ranging from a 20-40% chance across
any given location. While these values have changed little over the
past 24 hours, which should help to boost confidence in high wind
not materializing, BUFKIT soundings across Central Montana (i.e.
Rogers Pass and Helena) support wind values of 40kts around 1500ft
AGL and 50kts at 3000ft AGL overspreading the area between 19-23z.
This timing, which is during peak mixing, also coincides with the
passage of the shortwave moving over the Northern Rockies and
increasing pressure rises pushing southeast behind a cold front
diving southeast from North Central and into Southwest Montana.
Furthermore, ECMWF EFIs with respect to wind gusts across Central
Montana range from 0.6 to nearly 0.8, with these values supporting
the potential for an unusual to very unusual wind event.

While not the most likely scenario there is the potential for a 1-
3hr window during the afternoon hours on Monday for several
locations across Central Montana to exceed high wind criteria, with
these areas being south of the Montana Hwy 200 corridor and north of
the US Hwy 12 corridor. Given the continued low probabilistic
support we will withhold issuing any High Wind Watches at this time,
but should ECMWF EFI and/or BUFKIT values increase with subsequent
model runs then future high wind highlights may be warranted.

Accumulating Snow from late Sunday night through Monday evening...

Winter Weather Advisories have now been issued for the Southern
Rocky Mountain Front, Big Belt, Bridger and Castle Mountains, Little
Belt and Highwood Mountains, Bears Paw Mountains and Southern Blaine
County where probabilities for 4" or more of snow range from a 50-
75%. While initially warm ground temperatures will lead to some
melting across these locations snowfall rates of 1/2" per hour or
more during the daylight hours, which have a 30-60% chance of
occurring, will lead to snow accumulating even on warm surfaces.

The Winter Weather Advisory for the East Glacier Park Region remains
in effect; however, there is growing concern that the combination of
heavy snow and strong winds could significantly reduce visibilities
west of East Glacier and over Marias Pass. Additionally,
probabilities for 8" or more of snow over Marias Pass are now at a
65% chance, with even a 25% chance of 12" or more of snow. Future
shifts may need to consider upgrading the advisory to a warning, but
for now we will hold onto the advisory to see if the trend for
higher snowfall amounts holds. - Moldan

&&

.AVIATION...
23/18Z TAF Period

Mostly mid to high cloud cover this afternoon. Breezy west to
southwest winds continue across the North-Central plains this
afternoon. Beginning early Monday morning, a low pressure system
will bring light rain/snow to lower elevations. There may be a
brief lull before a cold front brings a better wave of rain/snow
and a west wind shift towards the end of the TAF period.
Precipitation will bring instances of MVFR to IFR cigs/vis. There
will be mountain obscuration Monday morning due to precipitation
and lower ceilings. -Wilson

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  55  39  45  21 /  20  30  80  50
CTB  50  31  36  14 /  10  20  90  30
HLN  45  34  40  19 /  10  20  80  30
BZN  50  32  44  14 /   0  20  80  10
WYS  43  24  34   3 /   0  20  80  20
DLN  49  32  45  11 /   0  10  50   0
HVR  55  29  39  16 /  10  20  90  60
LWT  56  34  44  17 /  10  20  80  40

&&

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

&&

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