315
FXUS65 KTFX 290526
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1126 PM MDT Wed Oct 28 2026

Aviation Section Updated.

.KEY MESSAGES...

- Snow & rain showers continue along the Rocky Mountain Front
  this afternoon and into Thursday.

- A cold front brings cooler temperatures Thursday and Friday.

- Increasing chances for widespread precipitation this weekend.


&&

.UPDATE...
/Issued 730 PM MDT Wed Oct 28 2026/

Tonight fog will form along the Hi-Line between Cut Bank and
Harlem and in the Golden Triangle Region (Region from Cut Bank to
Great Falls to Havre). For the update I increased maximum relative
humidity across a portion of North-central Montana. I also
increased sky cover across North-central Montana through Noon
tomorrow to better reflect current satellite imagery and forecast
trends. I adjusted PoPs this evening to better reflect current
radar imagery. The rest of the forecast is on track. -IG


&&

.DISCUSSION...
/Issued 730 PM MDT Wed Oct 28 2026/

 - Meteorological Overview:

Zonal to southwest flow aloft this afternoon into Thursday will
continue to stream moisture over the Continental Divide. As a
result, isolated to scattered rain/snow showers will be persistent
primarily along the Northern Continental Divide and Rocky
Mountain Front this afternoon into Thursday morning. A cold front
currently along the Hi-Line pushes south across the state today
into Thursday, bringing cooler temperatures to the region for
Thursday and Friday. The front also brings another slight chance
for patchy fog to develop across North-Central MT tonight into
Thursday and Friday morning.

A digging trough from British Columbia/Pacific Northwest Coast
increases southwest flow aloft, bringing warm air advection and
moisture Friday. Precipitation chances increases throughout
Friday across Southwest MT. However, better chances for widespread
precipitation across the state arrives Saturday into Sunday with
a low pressure system, with precipitation lingering into Monday.
So far, the main message with this system is minor snow at pass
level with more moderate accumulations at the higher mountain
peaks, and rain/snow at lower elevations (light snow trending
more late Sunday into Monday).

Behind that system, ensembles are hinting at a ridge building in for
the middle of next week. This trends drier conditions with
temperatures building back to near or above normals, with some
uncertainty in how much of a warm up there is.

 - Forecast Confidence & Scenarios:

Fog Tonight:

Low-level subsidence behind this cold front passage can allow for
patchy fog development across North-Central MT later tonight into
Thursday morning. There`s a 30-60% chance for fog to develop
across North-Central MT, isolated 10-30% chances for visibility to
drop to a half mile or lower with fog. One limiting factor is a
low stratus deck prohibiting fog development. The potential for
fog development extends into Friday morning as well with higher-
res and medium-res models showing low level moisture lingering.
Depending on how deep that low level moisture is, there is a very
low chance for light freezing drizzle to develop along the Rocky
Mountain Front (10% chance).

Snow Along Northern Rocky`s Through Thursday:

Not much has changed in terms of the forecast and impacts of the
snow along Marias Pass and the Rocky Mountain Front foothills. Minor
snow accumulations of 2-4" is expected along Marias Pass, with
little accumulations towards the Rocky Mountain Front. Weak low
level frontogenesis along the cold front can bring moderate snow
rates along the mountains this evening.

Weekend Storm System:

There remains some uncertainty with the weekend storm system as
the low track will play into snow accumulations. Warm air
advection Friday into Saturday may make snow accumulations
struggle along mountain passes/higher Southwest MT valleys,
keeping the bulk of the snow at the higher peaks. Models have been
trending colder air moving in Sunday on the back edge of the low
pressure system, where there will be better chances for minor snow
accumulations at mountain passes. There`s a 20-60% chance for 3"
of snow at pass level in Southwest MT. Light snow looks to mix
down to lower elevations Sunday/Monday morning at times but
accumulations look to be light to minimal at this time. -Wilson

&&

.AVIATION...
29/06Z TAF Period

VFR conditions will prevail at all terminals except for the KCTB,
KGTF, and KHVR terminals during this TAF Period. At the KCTB, KGTF,
and KHVR terminals between 29/06Z and 29/16Z there is a 60 - 80%
chance for fog with about a 50% chance for fog to reduce visibility
to one mile or less between 29/10Z and 29/14Z. However currently
there are low clouds at the KHVR and KCTB terminals which could
prevent fog from forming. At the KCTB terminal IFR-level ceilings
will prevail during the duration of this TAF Period. Across North-
central Montana there will be periods of mountain obscuration
during the duration of this TAF Period. -IG


&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  28  40  30  40 /   0   0   0   0
CTB  25  35  26  36 /  50   0   0  10
HLN  26  48  28  46 /   0   0   0   0
BZN  24  47  26  45 /   0   0   0  10
WYS  14  45  22  48 /   0   0   0  10
DLN  23  43  30  46 /   0   0   0  10
HVR  24  41  24  44 /  10   0   0   0
LWT  28  45  27  45 /   0   0   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 6 AM MDT Thursday for East Glacier
Park Region.

&&

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