Helena Valley, Montana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

940
FXUS65 KTFX 192149
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
249 PM MST Fri Dec 19 2025

.KEY MESSAGES...

- Rain/snow/wintry mix showers continue across Southwest MT this
  afternoon, with an isolated snow squall possible along the
  frontal passage up on mountain passes.

- Gusty winds decreases from north to south through the rest of
  the day.

- Minor snow lingers along the Northern Continental Divide Saturday.

- Daily chances for mountain snow with slight chances for rain/snow
  at lower elevations continue next week.

&&

.DISCUSSION...

 - Meteorological Overview:

The front continuing to move south through Southwest MT this
afternoon will bring minor mountain snow with lower elevation
snow/wintry mix showers. Warmer surfaces temperatures at lower
elevations will make any snowfall struggle to accumulate, but
can`t rule out an inch of accumulations from a moderate snow
shower. Snow squall chances look to be on the low end, but can`t
rule out one or two over the mountain passes. Farther north, a
Canadian Front will continue to bring in colder temperatures,
with the MT/Canadian border already dropped into the single digits
this afternoon. Gusty winds continue along the MT Highway 200
corridor this afternoon, but once that colder arctic air works in
the winds will begin to decrease.

Westerly flow aloft will keep streaming in moisture and orographic
lift for minor snow along the Northern Continental Divide/Eastern
Glacier Park region from tonight through the day Saturday.
Though, the rest of the region will likely get downsloped and
remain dry for Saturday.

On Sunday, a better upper-level wave coming through will bring
better chances for light mountain snow and lower elevation rain/snow
through Monday for mainly the Rocky Mountain Front and Southwest
MT.

The pattern shifts to more southwest flow aloft, keeping above
average temperatures across the region through mid next week.
Daily chances for lighter mountain snow and lower elevation
rain/snow continues next week.

 - Forecast Confidence & Scenarios:

Winds for the rest of today:

Winds generally have down trended sooner than forecasted across
the North-Central MT plains through the I-90 corridor. This has
led to the early cancellation of the High Wind Warnings there. Hi-
res guidance showed a lingering mid level jet max continuing to
mix down strong winds along the MT Highway 200 corridor through
the afternoon hours, so I left those High Wind Warnings in effect
until the evening. With the front moving through the Southwest,
there`s still a good chance for some strong winds to mix down to
the surface through the rest of the afternoon as well.

Mountain Snow Through Saturday:

Nothing has changed too much with the existing winter weather
advisories across Southwest MT. The front will continue to bring
moderate snow/snow showers, which will still bring additional
minor snow accumulations of 2-4" at pass level through tonight.

For the Northern Continental Divide/Eastern Glacier Park area,
snow as lightened up this afternoon. Therefore, I cancelled the
Winter Weather Advisory early. Incoming moisture and vorticity
maximums aloft passing through the area starting tonight will
bring another round of snow showers. There is a 70% chance for 4"
of snow along Marias Pass through Saturday afternoon. Minor snow
accumulations expected at pass level has prompted another issuance
of a Winter Weather Advisory for tonight through tomorrow
afternoon. -Wilson

&&

.AVIATION...
19/18Z TAF Period

The front will bring a wintry mix to Southwest MT this afternoon
through 19/21z-19/23z. Moderate showers developing along the front
brings a slight chance for IFR visibilities. Gusty winds continue
this afternoon, though the strongest winds have passed across the
North-Central MT plains. In the Southwest, once the front has
passes through, winds will decrease. A Canadian cold front will
bring a short period of IFR clouds to KHVR this afternoon. -Wilson

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  28  40  26  42 /   0   0   0   0
CTB  16  35  23  37 /  10   0   0   0
HLN  24  38  21  39 /  10  10   0  10
BZN  18  37  18  40 /  40   0   0  20
WYS   8  26  14  36 /  90  10  20  90
DLN  18  34  19  39 /  30   0   0  20
HVR   4  30  19  36 /  20  10   0   0
LWT  21  36  24  41 /  10   0   0  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 8 PM this evening to 5 PM MST
Saturday for East Glacier Park Region-Southern Rocky Mountain
Front.

High Wind Warning until 6 PM MST this evening for Fergus County
below 4500ft-Judith Basin County and Judith Gap-Little Belt and
Highwood Mountains-Madison River Valley-Snowy and Judith
Mountains.

High Wind Warning until 9 PM MST this evening for Beaverhead and
Western Madison below 6000ft-Big Belt, Bridger and Castle
Mountains-Gallatin and Madison County Mountains and Centennial
Mountains-Ruby Mountains and Southern Beaverhead Mountains.

Winter Weather Advisory until midnight MST tonight for Gallatin
and Madison County Mountains and Centennial Mountains.

Winter Weather Advisory until 9 PM MST this evening for
Northwest Beaverhead County.

&&

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