669
FXUS65 KTFX 011439
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
739 AM MST Mon Dec 1 2025

.KEY MESSAGES...

 - Gusty winds today will result in localized blowing and
   drifting snow.

 - Widespread snowfall expected tonight through Tuesday night,
   with generally light accumulations at lower elevations with
   more notable accumulations in the higher terrain.

 - Another widespread snowfall event is possible over the
   weekend.

&&

.UPDATE...

Today it will warm up with winds increasing this afternoon and evening
especially along the Rocky Mountain Front and plains west of
I-15 with isolated areas of blowing snow. This afternoon/evening
snow will begin to develop along the Continental Divide and spread
east to the valley floors by Tuesday morning. For the update, the
Cold Weather Advisory was cancelled, due to wind chills being
warmer than 20 below zero across the area and there being no
threat for them to get back to 25 below zero or colder. PoP grids
across most of North-central, Central, and Southwestern Montana
were increased this afternoon through tonight to better reflect
the latest hi-res model guidance. The rest of the forecast is on
track. -IG

&&

.DISCUSSION...
/Issued 450 AM MST Mon Dec 1 2025/

 - Meteorological Overview:

Transient upper level ridging will slide across the area today,
which will result in some gusty winds across the plains today.
These winds have already started to make their presence known
overnight, and have been hard at work eroding the arctic air mass
and as a result many areas were warmer at 3AM than they were at
sunset last night. Things have been a bit different in the valleys
of Southwestern Montana, however, where temperatures have
remained colder due to the mountains keeping the cold air locked
in place.

Snow will return to the area later today and tonight as a
shortwave trough approaches from the northwest. While snowfall
will be heaviest over the higher terrain, most areas should see at
least some light snowfall between tonight and Tuesday as this
system moves through. Colder air will return to the area behind
this system, but temperatures will not be quite as cold as they
were over the weekend.

Behind this system, more tranquil but slightly breezy conditions
appear likely as northwesterly flow aloft sets up across the area.
Unsettled weather looks to make a return Friday or Saturday,
however, as yet another disturbance moves through the area.

 - Forecast Confidence & Scenarios:

Blowing snow today: As upper level ridging builds into the area,
winds across the plains will increase, which could result in some
blowing and drifting of the snowpack across the area. However,
with only a minimal snowpack across the area any blowing snow
concerns will be short lived.

Late week snow: While the arrival of some snowfall Friday and
Saturday is appearing more and more likely, there remains some
uncertainty as to how much snow will fall and how widespread an
area the snow will affect. Right now the most likely scenario
appears to be a quick hitting snowfall that drops anywhere between 1-
4 inches across the lower elevations, but I can`t rule out a
scenario where northerly winds behind this system bring some more
snow to the northerly upslope areas. Ludwig

&&

.AVIATION...
01/12Z TAF Period

Aside from some low stratus and thin fog at KHLN this morning, VFR
conditions are expected across the area through this evening.
However, expect cigs to begin to lower overnight tonight with some
snow moving into the area overnight tonight, bringing reductions
in vis and cigs. Ludwig

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  34  28  34  17 /  10  40  90  60
CTB  31  23  33   8 /   0  30  70  30
HLN  34  25  35  18 /  10  50  80  50
BZN  31  21  35  15 /   0  50  80  50
WYS  25  15  28   6 /  10  70  90  40
DLN  36  23  37  15 /   0  40  40  20
HVR  29  20  35   5 /  10  40  60  30
LWT  35  23  33  13 /   0  40  80  60

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 5 PM this afternoon to 11 PM MST
Tuesday for East Glacier Park Region-Southern Rocky Mountain
Front.

Winter Weather Advisory from 11 PM this evening to 5 AM MST
Wednesday for Big Belt, Bridger and Castle Mountains-Gallatin
and Madison County Mountains and Centennial Mountains-Little
Belt and Highwood Mountains-Snowy and Judith Mountains.

Winter Weather Advisory from 5 AM Tuesday to 5 AM MST Wednesday
for Cascade County below 5000ft-Fergus County below 4500ft-Gates
of the Mountains-Helena Valley-Judith Basin County and Judith
Gap-Upper Blackfoot and MacDonald Pass.

&&

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