643
FXUS65 KTFX 032337
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
437 PM MST Sat Jan 3 2026

Aviation Section Updated.

.KEY MESSAGES...

 - Areas of low clouds and fog persist across Hi-line locations through
   tonight with some overnight patchy light freezing rain or
   drizzle possible.

 - Periods of mainly mountian snow will primarily affect areas near
   the continental divide through the upcoming week.

 - Windy conditions developing across north-central Montana this
   weekend continue into the next week, peaking on Tuesday.

 - Well above average temperatures cool to slightly above above
   average by the middle of next week.

&&

.DISCUSSION...
/Issued 236 PM MST Sat Jan 3 2026/

 - Meteorological Overview:

The area remains beneath a somewhat moist southwesterly flow aloft
downstream of an offshore upper level trough that gradually opens
while shifting inland through Monday. A series of mostly
disorganized disturbances and associated moisture moving out of the
trough and across the Northern Rockies and MT will favor areas near
the continental divide for periods of precipitation through Monday. A
few scattered showers are possible with the passage of these
disturbances further east across the forecast area, mainly overnight
tonight and again on Monday. Snow levels from 6000-7000ft tonight
will gradually lower to around 5000 ft by Sunday night. Areas along
the divide in Glacier NP and near the ID/WY border near Yellowstone
NP will see the most persistent periods of snowfall through Monday
thanks to orographic enhancement with most other mountain ranges and
passes expected to see more intermittent snow and minimal
accumulation. A shallow cold airmass is likely to linger along the
Hi-line and Marias/Milk River valleys through Sunday morning. Low
clouds and areas of fog are likely to redevelop this evening in
these areas with some risk for spotty light freezing rain showers
overnight.

Temperatures across the majority of the forecast area will be well
above seasonal averages again on Sunday before cooling slightly
early next week as heights fall with the upper trough shifting
inland. By Tuesday, a more zonal flow develops across the Northern
Rockies and MT as energy from the Gulf of AK begins to carve out
deeper troughing across western Canada. Southwest and eventually
westerly flow across the region will increase each day through
Tuesday, supporting windy conditions across much of the area going
into early next week with the strongest winds looking to occur on
Tuesday. Another series of shortwave disturbances is likely to move
through as the colder trough shifts across the western US/Canada
mid to late next week. This will bring some additional cooling,
but the colder continental air looks to stay north of the area,
keeping overall temperatures still slightly above seasonal for
early January. Timing of individual waves and moisture is still
uncertain but this pattern would favor additional rounds of
mountain snow with some opportunities for lower elevation snow
showers. Hoenisch

 - Forecast Confidence & Scenarios:

The coverage of showers across the north-central MT plains tonight
is likely to be fairly scattered with only a 10-20% chance of
measurable freezing rain for most areas along the Hi-line and
possibly as far south and west as Ft Benton and the Missouri
Breaks. The risk for measurable freezing rain increases to around
40% for areas along the Milk River east of Harlem.

Periods of snow over the next 48 hrs will add up to 6 inches or more
at elevations above 7000 ft in Glacier NP and along the MT/ID border
near Yellowstone NP. Snowfall amounts diminish quickly at lower
elevations and moving south from Glacier NP and north from the ID
border with around 2-4 inches expected over Marias PAss and in
West Yellowstone over the 2-day period. Targhee and Raynolds
passes into ID are likely to receive several inches of snow
tonight through Monday but impacts diminish quickly north of the
border.

Locally strong wind gusts (in excess of 55 mph) are likely as early
as Sunday along the immediate east slopes of the Rocky Mtn Front
with a 50% probability for gusts of this magnitude as far east as
Cut Bank on Monday. By Tuesday, the probability for gusts in excess
of 55 mph increases to 80% at Cut Bank and 30-50% across Cascade and
Judith Basin counties. Probabilities for gusts in excess of 75
mph on Tuesday are 60% or higher along the Rocky Mtn Front including
Browning. Hoenisch

&&

.AVIATION...
04/00Z TAF Period

Initial concern this TAF period will be for persistent low clouds
and fog across portions of the Hi-Line and adjacent areas.
Scattered precipitation moves across the Continental Divide this
evening and tonight, bringing a narrow window for light rain at
lower elevations of Central and North-central Montana. Areas where
surface temperatures remain below freezing, including KHVR, will see
the risk for brief pockets of freezing rain.

This system moves away heading into Sunday. As it does, an increasing
pressure gradient will combine with increased southwesterly flow
aloft to result in a breezy day for many areas Sunday. Areas where
surface winds are slow to increase, such as the Gallatin Valley
(KBZN), will see a low-level wind shear concern develop Sunday.
-AM

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  37  53  31  47 /  20   0   0   0
CTB  25  48  26  42 /   0  10   0   0
HLN  33  48  28  42 /  30  10  10  10
BZN  30  48  27  43 /  30   0  10  20
WYS  26  36  24  34 /  90  60  60  70
DLN  31  46  28  42 /  40  10  10  10
HVR  17  45  26  41 /  20   0   0   0
LWT  35  51  29  47 /  20   0   0  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&

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