Lewistown, Montana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

074
FXUS65 KTFX 240954
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
254 AM MST Sat Jan 24 2026

.KEY MESSAGES...

 - A round of snow develops today, lasting into early Sunday.

 - Trending milder heading into next week.

 - Breezy at times late weekend through much of next week.

&&

.DISCUSSION...

 - Meteorological Overview:

A modest but weakening upper level jet with mid level shortwave
will progress southward within a cyclonic northerly flow aloft
through the day today into tonight across the region. The result
will initially be for increased cloud cover early this morning
before better forcing arrives through the day. As the better
support arrives through the day, mainly light snow will develop
across much of the region. Areas that look to see greatest impacts
from snow will be between Great Falls and Lewistown, including
the northerly upslope regions in the Little Belts. The northern
portions of the Gallatin and Madison ranges also look to get in on
accumulating snowfall later in the day today into tonight. Snow
gradually diminishes late tonight and early Sunday as upper level
support wanes.

As the aforementioned system departs tonight, clearing skies
toward daybreak across the Hi-Line will foster temperatures once
again dropping below zero. Southerly to southwesterly winds
developing through the day Sunday will help moderate most areas,
though areas near and east of Havre look to hang on to the colder
temperatures for at least another day. A strengthening pressure
gradient along the Rocky Mountain Front Sunday evening will look
to develop a period of breezy winds into Monday morning. Although
these winds do not look to be overly strong, temperatures
remaining below freezing in this area will allow for any snow that
does fall today into tonight to drift at the very least.

Upper level ridging develops, and largely looks to persist
through much of next week. A continued moderating trend into early
next week is forecast, with dry conditions favored. Weak waves
cascading down the east side of the ridge may promote light
precipitation at times, but the timing and location of any
specific wave is very low confidence at this time. -AM

 - Forecast Confidence & Scenarios:

Snow Today and Tonight:

Northerly upslope areas, including the Little Belts, Snowies, and
the northern end of the Madisons and Gallatins look to be most
favored for snow today into tonight. Forcing for ascent elsewhere
looks to be a bit more nebulous and more brief in nature, which
will help keep snowfall amounts a bit lower. The probability for 3
inches of snow is highest in the Little Belts and west end of the
Snowies, sitting between 50 and 80%.

Rocky Mountain Front wind and potential for blowing snow:

Northerly flow aloft is usually not the most conducive setup for
breezy winds along the Rocky Mountain Front, but near the surface
a pressure gradient looks to develop late afternoon Sunday into
Sunday night. Latest in-house guidance suggests the pressure
difference between Kalispell and Cut Bank will peak between 10 and
15mb Sunday evening or Sunday night. Sustained westerly to
southwesterly winds along the Northern Rocky Mountain Front will
increase as a result, and be sufficient (combined with
temperatures that remain below freezing) to at the very least
drift any existing relatively fresh snowpack. Blowing of snow is
not out of the question, and will ultimately depend on just how
much snow falls today and tonight along the Rocky Mountain Front.
25th percentile sustained wind (75% chance for a stronger
sustained wind) is around 25 mph along the Rocky Mountain Front
Sunday evening through Monday morning.

Ridging next week:

Cluster guidance and associated ensembles are essentially
unanimous in a period of upper level ridging being in place
through the upcoming work week. Small embedded features within the
ridging will promote very low-end precipitation opportunities at
times next week, but the main takeaway is for another period of
drier conditions with near to above average temperatures heading
into the end of January.
-AM

&&

.AVIATION...
24/06Z TAF Period

Cloud cover increases tonight in advance of an approaching
shortwave embedded within a cold northwesterly flow aloft. Areas
of light snow and associated low VFR/MVFR/IFR conditions will
increase from north to south roughly after 24/12Z. The worst
conditions will be over and near the north/northwest oriented
foothills of the central island ranges. Another subtle shortwave
moves in tonight and will maintain periods of light snow and
degraded flight categories. - RCG

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  22  -1  25  17 /  40  60   0   0
CTB  19  -6  26  16 /  30  30   0   0
HLN  21   3  24  10 /  50  60   0   0
BZN  20   4  22   3 /  30  40  10   0
WYS  17  -5  17  -9 /  40  50  10   0
DLN  27   7  26   8 /  10  30  10   0
HVR  11 -10  15   3 /  40  20   0   0
LWT  17  -8  20   7 /  70  80  10   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Cold Weather Advisory until 9 AM MST this morning for Fergus
County below 4500ft-Snowy and Judith Mountains.

Winter Weather Advisory until 5 AM MST Sunday for Fergus County
below 4500ft-Judith Basin County and Judith Gap-Little Belt and
Highwood Mountains-Snowy and Judith Mountains.

&&

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