741
FXUS65 KTFX 131139
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
539 AM MDT Mon Oct 13 2025

Aviation Section Updated.

.KEY MESSAGES...

- Snow over central and north-central Montana diminishes later
  this morning, although lighter snow may persist through Tuesday
  morning along the divide.

- Temperatures slowly warm to near average by the end of the
  week,but there will be day to day opportunities for scattered
  shower activity and mostly mountain snow, especially Wednesday
  through Friday.

- Periods of breezy to windy conditions are expected heading into
  the weekend.

&&

.DISCUSSION...
/Issued 332 AM MDT Mon Oct 13 2025/

 - Meteorological Overview:

Cold northeasterly upslope flow will persist over central and
north- central MT for much of today while warmer air and moisture
overrun the shallow colder air via H500 southwesterly flow. This
will maintain cold and damp conditions for the northern half of
the forecast area today. Snowfall and wintry impacts will peak
this morning before diminishing and retreating to areas along the
Rocky Mountain Front later this afternoon into tonight.

A closed low diving southward along the Pacific Northwest coast
will continue to support difluent flow over the Northern Rockies
for the first half the week. Moisture and weak shortwaves moving
in from the southwest will bring periods of rain showers and
higher mountain snow tonight into Tuesday, mostly for southwest
MT. The cold air over central and north-central MT will slowly
retreat northward heading into mid- week.

The Pacific Northwest closed mid- level low is expected to peak
in intensity over central CA before weakening and swinging
northeastward through the Great Basin and eventually reaching
eastern MT by around Thursday. The evolution of this feature will
be complex as it approaches the region, so the precise locations
of its low pressure center(s) and resultant precipitation
locations is still a bit on the fuzzy side. Overall expect the
most widespread rain and mountain snow to occur between Tuesday
night and Friday. With milder Pacific air moving in, snow impacts
look to be on the minor side and mostly confined to mountain
areas.

Ridging aloft with stronger westerly flow looks to at least
briefly move through the Northern Rockies heading towards the
weekend followed by more passing troughs in an increasingly
northwesterly flow aloft. This will result in periods of breezy to
windy conditions, though the timing details still need to be
worked out depending trough and ridge phasing. - RCG

 - Forecast Confidence & Scenarios:

Snow today through Tuesday morning...

Warm air aloft overrunning cold northeasterly flow in the low
levels continues to bring snow this morning for central and north-
central locations along the divide and near the central island
ranges. The focus of the heaviest snow initially set up in the
Boulder and Helena areas, a little farther south than originally
expected. The Helena Airport set a 24 hour snowfall record
yesterday with 2.6 inches. The main area of snow has since lifted
northward toward the Southern Rocky Mountain Front/central island
ranges and their adjacent plains. Although snowfall has generally
fallen below expectation for the winter storm warned area, I will
leave the warning posted for a bit longer with a general 1 to 4
inches of snow still expected through the morning hours. Slippery
roads and power outages from heavy, wet snow will continue to be
the primary impacts. Snow gradually diminishes later this morning
into the afternoon, though light snow may persist along the Rocky
Mountain Front through Tuesday morning. - RCG

&&

.AVIATION...
13/12Z TAF Period

Snow over central and north-central MT will slowly retreat to
areas along the Rocky Mountain Front as the day progresses;
however, MVFR/IFR conditions will generally persist through 14/00Z
due to lingering patchy fog and low stratus. There will be some
improvement tonight, but there will be lingering MVFR conditions
throughout the night. Additionally, while light snow continues
along the divide tonight, another shortwave moves into southwest
MT and brings more low VFR/MVFR ceilings and mountain obscuration.
- RCG

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  34  24  42  28 / 100  20  20  30
CTB  30  22  41  23 /  70  20  10  10
HLN  37  25  44  30 /  70  20  40  50
BZN  44  24  49  30 /  10  10  30  60
WYS  49  25  51  29 /   0  40  60  80
DLN  46  26  50  32 /  10  30  40  50
HVR  38  24  49  30 /  40  10  10  30
LWT  37  22  48  29 /  50  10  20  60

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until noon MDT today for East Glacier Park
Region-Gates of the Mountains-Southern High Plains-Southern
Rocky Mountain Front.

Winter Weather Advisory until noon MDT today for Cascade County
below 5000ft-Eastern Pondera and Eastern Teton-Elkhorn and
Boulder Mountains-Helena Valley-Judith Basin County and Judith
Gap-Little Belt and Highwood Mountains-Northern High Plains-
Upper Blackfoot and MacDonald Pass.

&&

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