452
FXUS65 KTFX 051755
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1055 AM MST Fri Dec 5 2025

Aviation Section Updated.

.KEY MESSAGES...

- Light snow this morning, diminishes in many areas for a few
  hours, before another round of snow moves in this evening.

- Some rain could mix in at times at lower elevations over the
  next few days.

- Several periods of strong winds are possible over the next few
  days as well, some of which could require high wind statements.

&&

.UPDATE...
/Issued 758 AM MST Fri Dec 5 2025/

Snow will continue in the mountains of Central and Southwestern
Montana today with a band of snow impacting a portion of North-
central Montana this afternoon through tonight. There will also be
light snow in some of the valleys of Southwestern Montana this
afternoon through tonight. For the update, PoPs were adjusted this
afternoon/evening to account for the frontal timing in the latest
hi-res model guidance. Since snow has ended in the Gallatin
Valley and in the Boulder and Elkhorn Mountains those Winter
Weather Advisories were cancelled. The rest of the forecast is on
track. -IG

&&

.DISCUSSION...
/Issued 408 AM MST Fri Dec 5 2025/

 - Meteorological Overview:
The overall pattern change from a drier November, to a wetter more
typical La Nina weather pattern is beginning. Expect weather
systems to move mainly from west to east across Montana on regular
intervals, generally every 1 to 3 days over the next few weeks.
Each weather system might not be as strong as the previous weather
system, but do expect periods of precipitation, along with short
periods of mild temperatures, followed by short periods of cold
temperatures. That being said, the first wave of moisture is
starting to exit the CWA this morning. Light snow is diminishing
over Southwest MT. The current advisories set to expire at 11 AM
in the Boulder and Bozeman area might be cancelled a bit early, as
the snow is diminishing. Otherwise, a break in the precip is
expected for a few hours this morning into early this afternoon.

By this evening, the next, and a bit stronger wave of
precipitation will move from west to east across the CWA. This
wave tonight will pack more of a punch, and also impact a larger
portion of the CWA. This wave of moisture should arrive along the
divide by 4 PM, and then move rather quickly across the CWA this
evening and overnight. There is the potential that a snow squall
warning might be needed for a few areas along the I-15 corridor
from Helena to Great Falls early this evening if the system is
early. Otherwise, the band of heavier snow is likely to occur
after 7 PM, likely getting a bit late for snow squall warnings.
Since this band is quick in the Great Falls/Helena area, and it
could mix in with rain, no advisory at this time for this area.
For areas north/east of Great Falls, it will be later, and mostly
snow, thus an advisory was issued. Overall for the mountains, a 6
to 12 inch snowfall is possible tonight, thus the current warnings
will remain. For the winter storm watch along the divide, the
highest snow amounts are right near the divide, thus day shift
will consider if an advisory might be better for that area.
Otherwise, the main concern this evening will also be for blowing
snow. A few ridge top could have wind gusts near 60 mph as the
front moves through. Overall, most of the snow moves out by
Saturday afternoon.

For Sunday through Friday, the progressive westerly flow pattern
will continue. Just scattered mountain showers are mainly expected
Sun/Mon...but by Tue the precip becomes more widespread once
again. From Tue thru next Friday, there is the potential for daily
snowfall amounts of 2 to 4 inches in the mountains, with isolated
higher amounts. At lower elevations, rain will mix in at times
during the week, so snow amounts are very minor, with most areas
seeing less than a quarter of an inch, if that, on a daily basis.
Lower elevation temperatures will generally be above normal for
all of next week. There will also be the potential for several
periods of strong winds. Again, almost daily Sun through Thu there
is the potential for some areas to be near high wind warning
criteria.

 - Forecast Confidence & Scenarios:
The main concern in the short term is the band of snow that will
move across the CWA this evening. The western portions of the CWA
will be affected during the evening hours, while blowing snow
increases, and poor visibility will affect the eastern portions of
the CWA. There is the potential that snow squalls might be needed
if temperatures cool quicker this afternoon and the snow arrives a
bit early.

Otherwise, the potential for strong winds will be a concern over
the next few days. Right now Tuesday is showing the highest
probability of strong winds, with near an 80 percent chance for
areas along the Rocky Mountain Front and around Cut Bank. Thus
high wind statements might be needed at times over the next few
days. Brusda

&&

.AVIATION...
05/18Z TAF Period

A moist and unsettled northwesterly flow aloft will remain over the
Northern Rockies for at least the next 24 to 48 hours. MVFR/IFR
clouds and mountain obscuration will mostly be confined to areas
near mountains through 06/00Z. Then a fast moving shortwave will
bring increased snow shower activity and some MVFR/IFR conditions to
all areas between 06/00 and 06/09Z. Steadier snow and degraded
flight categories will linger into Saturday in the mountains and
near the KHVR/KLWT areas. Mountain top winds will exceed 50 kts at
times during the passage of the shortwave which will increase
mountain wave turbulence and instances of low level wind shear.
- RCG

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  39  22  33  23 /  20  80  50  10
CTB  29  11  25  13 /  20  70  20  10
HLN  40  30  40  28 /  40  90  60  20
BZN  36  26  40  22 /  60  90  60  20
WYS  30  19  33  14 /  90  90  80  40
DLN  38  28  40  21 /  40  80  20  10
HVR  37  10  19   6 /  40  90  60  50
LWT  35  20  33  20 /  40  90  70  40

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Winter Storm Watch from 5 PM MST this afternoon through Sunday
morning for East Glacier Park Region-Southern Rocky Mountain
Front.

Winter Weather Advisory from 8 PM this evening to 5 AM MST
Saturday for Bears Paw Mountains and Southern Blaine-Eastern
Toole and Liberty-Fergus County below 4500ft-Hill County-
Northern Blaine County-Snowy and Judith Mountains-Western and
Central Chouteau County.

Winter Storm Warning until 2 PM MST Saturday for Big Belt,
Bridger and Castle Mountains-Gallatin and Madison County
Mountains and Centennial Mountains-Little Belt and Highwood
Mountains.

Winter Storm Warning until 5 PM MST Saturday for Northwest
Beaverhead County.

&&

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