696
FXUS65 KTFX 161655
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1055 AM MDT Thu Oct 16 2025

Aviation Section Updated.

.KEY MESSAGES...

- Scattered light rain showers and mountain snow continue
  today, mostly for central and southwestern areas east of I15.

- A quick moving trough and attendant cold front brings breezy
  to windy conditions and scattered rain and snow showers tonight
  through early Saturday.

- More unsettled conditions with periods of showers, mountain
  snow,and or breezy to windy conditions are expected Sunday into
  early next week while temperatures generally trend near
  average.

&&

.UPDATE...
/Issued 1023 AM MDT Thu Oct 16 2025/
No morning update planned today. Light rain/snow showers are
moving southward through the eastern portions of the CWA. That
should should continue into early afternoon before the showers
diminish. There is a very sharp clearing line for cloud cover over
the western half of North Central MT, with mostly sunny skies west
of a line from Great Falls to Havre.

Looking ahead, the main weather concerns over the next few days
will be increased winds Friday over the Rocky Mountain Front,
light rain/snow Friday night into Saturday, then another weather
system arrives late Sunday into Monday, with more wind/precip.
Brusda

&&

.DISCUSSION...
/Issued 1023 AM MDT Thu Oct 16 2025/

 - Meteorological Overview:

Lingering surface moisture and partial clearing skies have
resulted in patchy fog development over portions of central and
north-central MT during the overnight hours, which will continue
through mid- to late morning depending on cloud cover. An
elongated mid-level trough centered over the Great Basin will
continue to trek northeast into eastern MT by this evening. The
main precipitation area with this system has shifted east of the
forecast area, although there will be scattered shower activity
and light mountain snow though this afternoon, especially over the
Madison and Gallatin mountain ranges.

A fast moving trough and attendant cold front then quickly dives
southeastward out of BC/AB and brings breezy to windy conditions
and scattered rain/snow showers tonight through early Saturday.
Winds will increase along the Rocky Mountain Front tonight before
spreading eastward onto the plains on Friday. Then a quick round
of rain and snow showers sweep though in a northwest to southeast
fashion Friday evening and night. H700 temperatures will be cold
enough to lower snow level down to the plains/valley floors, but
accumulations looks to be negligible for most locations.

Transient ridging passes through the Northern Rockies later
Saturday into Sunday for a brief period of mild and drier
conditions. Another Pacific trough then brings another round of
winds, showers, and mountain snow later Sunday into early next
week while temperatures generally remain near average. The
progressive pattern continues for much of next week, but there a
discrepancies with the ridge and trough phasing among ensemble
members. - RCG

 - Forecast Confidence & Scenarios:

Rain, mostly mountain snow, and winds through early next week...

Precipitation associated with the trough moving out of the Great
Basin is expected to largely stay east of the forecast area. There
will be some scattered showers this afternoon over the plains
east of Great Falls to Havre line. Otherwise, the bulk of the
showers and mountain snow is expected over and near the Madison
and Gallatin ranges where light accumulating snow may pose minor
impacts to those with mountain outdoor interests.

The next opportunity for rain and snow showers will move through
the region from northwest to southeast late Friday afternoon
through early Saturday. Frontogenesis supported by H700
temperatures around -10C will drop snow levels down to the plains
and valley floors,especially for northern areas; however, this
system is rather moisture starved and its fast motion will limit
precipitation residence time. NBM snowfall exceedance
probabilities are not very impressive either, with mountain areas
seeing a 30 to 50% chance for accumulations over 1 inch. The
primary impact here will be short term visibility reductions from
localized heavier snow bursts.

The next trough arrives later Sunday into Monday, with mountain
areas and the central and southwestern valleys seeing the best
precipitation potential. Most of these areas have 30 to 50% chance
for a quarter inch of rain or liquid equivalent precipitation.
These probabilities drop to near zero over the plains due to
downsloping winds. Impactful snow accumulations in the mountains
look to mostly stay above pass level where there is around a 50%
chance for snowfall over 3 inches.

Periods of windier conditions are expected Thursday night through
Sunday. Mountain wave activity will increase winds along the
Rocky Mountain Front tonight before deep layer mixing moves these
winds onto the plains on Friday. Probabilities for wind gusts over
50 mph are running in the 70 to 90% range along the Rocky
Mountain Front and around 50% in the eastern Glacier/western Toole
zone. The north- central plains will generally see gusts in the
30 to 50 mph range on Friday, strongest southeast of a Great Falls
to Havre line.

All areas look to see increased winds Saturday night into Sunday.
Once again mountain wave activity will be responsible for
stronger winds Saturday night, not only for locations along the
Rocky Mountain Front, but also for the east/northeast slopes of
the central ranges. By Sunday, the windy conditions move east onto
the plains and even over the central and southwest valleys. The
highest probabilities for gusts over 50 mph will be along the
Rocky Mountain Front and over south to north oriented southwest
valleys. - RCG

&&

.AVIATION...
16/18Z TAF Period

Initial concern this TAF period will be for lingering areas of
rain and low clouds. These slowly diminish through the afternoon
as the responsible weather system moves slowly eastward, away from
the region. Attention then turns to increasing winds beginning
tonight, initially across the plains. A few instances of low-level
wind shear will be around before winds fully mix to the surface
during the day Friday across most areas. -AM

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  56  38  59  29 /  10   0  10  40
CTB  59  37  53  27 /   0   0  40  20
HLN  56  34  60  32 /  10   0  10  40
BZN  50  28  59  27 /  50  10   0  40
WYS  44  24  45  20 /  70  20   0  40
DLN  51  29  59  27 /  20   0   0  10
HVR  57  34  57  27 /  20   0  20  20
LWT  47  32  57  28 /  50  10  10  60

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&

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