309
FXUS65 KTFX 281730
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1030 AM MST Fri Nov 28 2025

Aviation Section Updated.

.KEY MESSAGES...

 -Widespread snowfall continues today, bringing reduced
  visibility and slick roadways to North Central and Southwestern
  Montana.

 -Coldest air of the season surges into the area today, with
  subzero lows expected tonight and tomorrow night.

 -Another round of snowfall expected around Tuesday and
  Wednesday, but snowfall is likely to be light.


&&

.UPDATE...
/Issued 842 AM MST Fri Nov 28 2025/

Snow has expanded to areas as far south as Bozeman so far this
morning with the colder airmass boundary already having pushed as
far south as Boulder and Toston by 8am. Northerly winds with gusts
in excess of 30 mph are occurring from the Rocky Mtn Front east
to around I-15 across north-central MT as cold surface high
pressure surges south along the east slopes of the Rockies. Winter
storm event forecast is largely on track with minimal changes
this morning except to adjust winds up a bit more in line with
observations and adjust pops/timing to align with observed trends
and incoming hi-resolution model data. With snow already occurring
in areas along the I-90 corridor and at least a couple of inches
expected as the stronger northerly winds push south into areas
from Whitehall east to Three Forks this afternoon, have added a
winter weather advisory for these areas as well for this afternoon
through early this evening. Hoenisch

&&

.DISCUSSION...
/Issued 842 AM MST Fri Nov 28 2025/

 - Meteorological Overview:

An upper level trough will continue to push through the Northern
Rockies today, bringing widespread snowfall and will usher in the
coldest air of the season thus far in its wake. Snowfall this
morning is generally confined to a band south of US 2 and north of
US 87/89, but will shift southward and expand as cold air
continues to surge southward and as the axis of the upper level
trough moves overhead. Snow will generally be light to moderate,
but a few areas of heavier snowfall will be possible, particularly
along the cold front that will push through southwestern Montana
today. Winds will also be elevated, particularly across the plains
and in some of the north/south oriented valleys of Southwestern
Montana, but the wet nature of the snow should prevent widespread
blowing snow issues.

Behind this system, surface high pressure will build into the
area, which will bring with it the coldest air of the season thus
far, with lows dipping below 0 for some, especially across the
plains, with daytime highs reaching the low 20s for most except
the most northern areas. This arctic high pressure system will
shift to the east early next week, which will allow warmer air to
work into the area from the southwest as it pulls away.

As warmer air works into the area, upper level ridging will
briefly work into the area next week, keeping our weather more
tranquil, at least for a day before the ridge breaks down as
another system dives in from the north. As it does, expect some
widespread snowfall across the area, though at the moment it
appears more likely than not that most areas will see just a light
snow event with this system. Another high pressure system will
follow this disturbance, which will bring with it another round of
colder than average (but not arctic) temperatures to the area for
the second half of the week.

 - Forecast Confidence & Scenarios:

Snowfall today: For the most part, snowfall today will be a
steady light snowfall across the plains, though a few areas of
heavier snowfall will be possible as evidenced by the early
morning presence of a snowfall band just north of Great Falls that
should move southward through the day. Across Southwestern
Montana, a few embedded heavier snow showers may be possible, so
anyone traveling today should be prepared for some changing
weather and road conditions. In addition to the falling snow, a
few localized areas of blowing snow will also be possible today
across the plains as winds gust to 30-35 mph. Blowing snow is less
likely to be an issue early in the day thanks to low/wet snow
ratios, but as snow ratios increase some blowing/drifting of the
snow will be possible.

Snowfall next week: Snowfall next week is likely to be a bit
lighter than the ongoing snowfall event, though a few ensemble
members across the suite of models do show a very low chance for
some more significant snowfall in excess of 6-8 inches across the
plains. While this appears to only have a 5-10% chance of
materializing, it is worth keeping an eye on for more significant
impacts. Ludwig

&&

.AVIATION...
28/18Z TAF Period

During the first 6 hours of this TAF Period there will be widespread
snow which will reduce visibility to at least IFR-levels and at
most terminals to LIFR-levels. After 29/02Z at most of the
terminals the snow will begin to diminish and visibility will
improve. However at the KHVR, KLWT, and KGTF terminals at least
MVFR-level ceilings will remain for much of the rest of the TAF
Period. There will be gusty winds during the first 6 hours of this
TAF Period which will lead to some blowing snow at all terminals.
During the duration of this TAF Period there will be mountain
obscuration across North-central, Central, and Southwestern
Montana. -IG

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  18   1  21  -4 /  90  60   0   0
CTB  14  -9  12  -9 /  80   0   0   0
HLN  26   1  22   5 /  90  20   0  10
BZN  33  -3  23   3 /  90  60   0  10
WYS  36  -4  24   6 /  80  60   0  10
DLN  40   4  27  12 /  70  20   0   0
HVR  20  -6   9 -16 /  90  80   0   0
LWT  21  -1  20  -1 /  90  80   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until 11 PM MST this evening for Cascade
County below 5000ft-Eastern Pondera and Eastern Teton-Eastern
Toole and Liberty-Southern High Plains-Southern Rocky Mountain
Front-Western and Central Chouteau County.

Winter Storm Warning until 5 AM MST Saturday for Bears Paw
Mountains and Southern Blaine-Fergus County below 4500ft-Hill
County-Northern Blaine County.

Winter Weather Advisory until 5 AM MST Saturday for Big Belt,
Bridger and Castle Mountains-Elkhorn and Boulder Mountains-
Gallatin Valley-Gates of the Mountains-Helena Valley-Judith
Basin County and Judith Gap-Little Belt and Highwood Mountains-
Madison River Valley-Meagher County Valleys-Snowy and Judith
Mountains.

Winter Storm Warning until 5 PM MST this afternoon for East
Glacier Park Region-Eastern Glacier, Western Toole, and Central
Pondera-Northern High Plains.

Winter Weather Advisory until 5 PM MST this afternoon for Upper
Blackfoot and MacDonald Pass.

Winter Weather Advisory until 8 PM MST this evening for Canyon
Ferry Area-Gallatin and Madison County Mountains and Centennial
Mountains-Missouri Headwaters.

&&

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