551
FXUS65 KTFX 041132
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
532 AM MDT Sat Oct 4 2025

Aviation Section Updated.

.KEY MESSAGES...

 - A Fall storm system affects the region through the weekend
   with progressively cooler temperatures and lowering snow
   levels.

 - Impactful snowfall is expected primarily in the mountains
   tonight through Sunday morning with some brief snow at lower
   elevations Sunday morning.

 - Gusty north winds and much colder temperatures Sunday will be
   followed by a widespread hard freeze at many locations Sunday
   night.

&&

.DISCUSSION...
/Issued 354 AM MDT Sat Oct 4 2025/

 - Meteorological Overview:

Precipitation coverage will increase this morning across
southwest MT as a closed upper level low lifts out of the Great
Basin into WY. Meanwhile, larger scale upper level troughing
across western Canada deepens with an initial embedded wave
dropping south out of BC into the Northern Rockies today before
another embedded shortwave, currently moving out of the Yukon/NWT,
sends a stronger cold front south along the Rockies tonight.

Height falls and cooling aloft beneath the deepening trough will
bring noticeable cooling today with afternoon high temperatures
mainly in the 50s and snow levels lowering to around 7000 ft by
late this afternoon. Precipitation increases late this afternoon
from Glacier NP south along the continental divide ahead of the
shortwave dropping south out of BC and intensifies tonight as the
secondary wave and strong cold front push south from Alberta. The
cold front surges south across most of north-central MT late
tonight and across southwest MT Sunday morning. Snow levels
rapidly fall with the cold front late tonight through Sunday
morning reaching as low as around 4000 ft across portions of
north-central MT and around 5500 ft across southwest MT.
Precipitation spreads south with the cold front overnight and
lingers across southwest MT into Sunday afternoon with higher
amounts focused over the Rocky Mtn Front and adjacent plains and
south through the mountains of central and southwest MT as well as
areas with northerly upslope enhancement adjacent to the central
MT mountains.

Gusty north winds follow the frontal passage late tonight through
Sunday morning as the colder airmass originating in NW Canada
slides south into the region, keeping daytime temperatures in the
40s or cooler for most areas. Precipitation will clear from north
to south Sunday afternoon. The lingering cold airmass will then
set the stage for the season`s first widespread freeze Sunday
night, with temperatures dropping into the 20s across much of the
region.

Early next week, upper-level ridging will return, bringing mainly
dry conditions and temperatures near or above seasonal averages by
Tuesday. Mild conditions are expected to persist through mid to
late next week, despite some model differences regarding a weak
upper-level disturbance moving out of the Great Basin. A larger-
scale trough from the Pacific is anticipated to approach by next
weekend.

 - Forecast Confidence & Scenarios:

A winter storm warning remains in place for Glacier NP and
adjacent areas with the spread in ensemble snow amounts
decreasing, leading to higher confidence in amounts in excess of 6
inches across higher elevations in the park. This includes Logan
pass where the probability for amounts in excess of 6 inches is
now 60%. High resolution models also suggest the potential for a
period of heavier snowfall with rates to around 1/hr possible
(20-30%) late tonight in western Glacier County as the front moves
south out of Alberta, which could impact US-89 from Kiowa north
to the international border.

Winter Weather advisories remain in place for areas from Browning
south along the Rocky Mtn Front and across the Little Belts as
well as the Gallatin and Madison Ranges in southwest MT where
accumulations of 4 or less are generally expected across the
higher elevations. While not impactful, snow levels could briefly
fall as low as around 3500ft across western portions of north-
central MT Sunday morning with some wet snowfall even occurring
for areas from Cut Bank south to Great Falls.

Minimum temperatures are expected to fall below freezing for all
areas Sunday night with an 80% or greater probability for
temperatures reaching 28F or less.

&&

.AVIATION...
04/12Z TAF Period

Precipitation increases across southwest MT this morning with
widespread MVFR conditions and mountain obscuration there while
primarily VFR conditions under mid to high level cloud-cover
persists across north-central MT into this afternoon.
Precipitation ahead of a frontal system moving out of western
Canada increases across western portions of north-central MT late
this afternoon and evening. A period of IFR/MVFR conditions in
precipitation and lower clouds spreads south across the region
tonight with gusty north winds also developing with the passage of
the frontal system. Hoenisch


&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  58  36  47  26 /  20  80  70   0
CTB  53  30  45  22 /  60  90  30   0
HLN  58  36  46  27 /  40  90  80  10
BZN  53  35  45  24 /  70  80  80  20
WYS  48  26  43  17 /  90  70  80  30
DLN  53  32  46  25 /  40  60  50  10
HVR  62  34  52  26 /  20  30  20   0
LWT  55  34  45  24 /  50  80  70  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning from midnight tonight to noon MDT Sunday
for East Glacier Park Region.

Winter Weather Advisory from midnight tonight to noon MDT Sunday
for Little Belt and Highwood Mountains-Northern High Plains-
Snowy and Judith Mountains-Southern Rocky Mountain Front.

Winter Weather Advisory from 6 PM this evening to 6 PM MDT
Sunday for Gallatin and Madison County Mountains and Centennial
Mountains.

&&

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