562
FXUS65 KTFX 241158
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
458 AM MST Mon Nov 24 2025

Aviation Section Updated.

.KEY MESSAGES...

 - Winter weather and cooler temperatures move into the area today
   bringing a chance for widespread snow across the region.

 - Localized freezing rain and minor ice accumulation possible
   along the Hi- Line today.

 - Generally drier conditions expected Tuesday and Wednesday with
   some light snow showers possible in the mountains.

 - Another round of snow and colder temperatures is possible later
   in this week into the weekend.

&&

.DISCUSSION...
/Issued 1205 AM MST Mon Nov 24 2025/

 - Meteorological Overview:

A shortwave will move across the area today bringing much cooler
temperatures and a chance for widespread snow. Snowfall will begin
along the Continental Divide and spread into the island ranges by
the late morning and continue into early Tuesday morning.
Precipitation along the lower elevations will initially start off
as rain and slowly transition to snow as the cold front progresses
southward through the afternoon and evening hours. Initial
snowfall accumulations will be lost to the warm surfaces but
advancing cooler air may allow for some minor accumulations at
lower elevations through late Monday night. There will be a
concern for freezing rain along portions of the Hi-Line,
particularly in Hill and Blaine counties which could cause slick
roads today.

Behind the shortwave, transient ridging will briefly keep the area a
little drier Tuesday into Wednesday before another shortwave trough
is expected to arrive by Thursday. Uncertainty still remains high
with how this system will play out but there is a chance for more
lower elevation snow and much colder temperatures that follow.


 - Forecast Confidence & Scenarios:

Freezing Rain Monday:

The latest HREF shows a greater than 80% probability of at least
0.01" accumulation along and north of US-2. Higher amounts decrease
in confidence pretty quickly but there is a 20% chance of isolated
freezing rain accumulations up to 0.05". One of the limiting factors
for impacts and accumulation will be the road and sidewalk
temperatures remain above freezing. But there is still a concern
that as temperatures fall to near freezing, any accumulation of
freezing rain along area roads will make things slick and become a
hazard to motorists.

The main concern will be along elevated surfaces including bridges,
power lines, and trees which will run cooler and be more susceptible
to accumulating ice. At this time widespread power outages and
falling tree limbs are not expected but if the freezing rain event
follows through with the higher amounts (closer to 0.05") there may
be an isolated power outage in the area.


Accumulating Snow Monday:

Rain showers will start to transition to snow late Monday morning
across the lower elevations as the cold front moves down with snow
levels expected to fall to around 2,000ft by the late afternoon.

For the most part, significant snowfall accumulation at lower
elevations is not expected at this time. Part of this is due to the
surface temperatures remaining above freezing leading up to this
event which will help to melt some of the first snowflakes.
Accumulations up to an inch are possible across the lower elevations
through very early Tuesday morning with the potential for some
higher amounts along the Canadian border.

Across the northern most portion of the Hi-Line, the HREF has a 40
to 60% chance of 2 or more inches of snow over the period with
probabilities dropping to less than 20% along US-2. Given the
combined threat of freezing rain with snowfall across the Hi-Line,
the current Winter Weather Advisory is sufficient for now as impacts
are otherwise expected to remain on the lower end.

As expected the highest snowfall amounts will be found in the
mountains. The Northern Rockies along the Continental Divide are
expected to see the highest amounts with HREF guidance suggesting a
greater than 70% chance for 6 inches or more along Marias Pass
through early Tuesday morning. When looking at the probability for
exceeding 9 inches of snow, right now any probability above 30% is
reserved for the highest elevations well above pass level. So
considering these factors, for now, the Winter Weather Advisory will
suffice. That being said, there is a concern for brief periods of
heavy snow along Marias Pass and should snowfall amounts start to
over-perform from the current forecast then a potential upgrade
may need to be considered.

Along the Little Belts, there is greater than 80% chance for 6 or
more inches at Kings Hill Pass with a 20% chance for 9 inches or
more.

Along the Bears Paw, there is a greater than 70% chance for 4 inches
or more with some of the higher elevations potentially seeing up to
6-8 inches.

For Bozeman Pass, there is a 50% chance of 2 inches or more with the
main concern being the morning commute as there could be a rain/snow
mix at pass level which could make things slippery.

Overall, the main concerns through Monday will be travel-related,
especially along the mountain passes. Those who venture out should
be prepared for sudden changes in road and weather conditions.


Strong Winds Monday:

A period of strong winds is possible, particularly along the Rocky
Mountain Front and including MacDonald Pass. Wind gusts up to 55 mph
are likely as the front moves through and any shower in the area may
help mix down some of those higher wind gusts. When considering the
need for a High Wind Warning, the potential window for exceeding
high wind criteria is only 1 to 3 hours and confidence in the higher
wind gusts occurring is around 30%. So for now there will not be any
additional wind headlines issued. But this will be monitored as the
winds may over-perform and a short-fused warning may be
warranted.


Cooler Pattern Next Weekend:

Overnight temperatures have warmed up a little bit for the weekend
into early next week compared to the previous model runs. Single
digit to mid teens are still possible for the lows but there is very
marginal confidence in some of the coldest ensembles playing out
right now. The difficulty in pinpointing exactly how cold it will
get is that the final answer will be dependent on how much snow
falls across the area. More snow equals colder temperatures. But if
this system remains on the drier side then some areas of below zero
lows are possible next Sunday and Monday but it will be hard to
reach those coldest temperatures without some snow cover to aid it
along.  -thor


&&

.AVIATION...
24/12Z TAF Period

An upper level disturbance will move over the Northern Rockies
through the day today, with an attendant cold front pushing south
from Southern Alberta and across North Central through Southwest
Montana between 15-21z Monday. This upper level disturbance will
bring low-VFR CIGS to all terminals throughout the duration of the
2412/2512z TAF period, with IFR/MVFR CIGS occurring along and
north of a KLWT to KGTF line. Periods of rain/snow will fall
throughout the day as the disturbance and cold front move
over/across the Northern Rockies, with even a threat for freezing
rain/drizzle along and north of the US Hwy 2 corridor prior to 18z
this afternoon. Mountains will be obscured for much of the next
24 hours. - Moldan

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  46  21  38  23 /  80  60   0   0
CTB  38  14  33  15 /  90  30   0   0
HLN  41  19  35  22 /  80  40   0  10
BZN  45  15  34  19 /  90  20   0  10
WYS  35   5  29  13 /  90  20   0  20
DLN  43  13  34  21 /  60   0   0  10
HVR  40  17  32  12 / 100  80   0   0
LWT  47  16  34  17 /  80  60   0   0

&&

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

Winter Weather Advisory until 11 PM MST this evening for Bears
Paw Mountains and Southern Blaine-Hill County-Northern Blaine
County.

Winter Weather Advisory until noon MST today for Eastern
Glacier, Western Toole, and Central Pondera-Eastern Toole and
Liberty.

&&

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