969
FXUS65 KTFX 081110
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
510 AM MDT Wed Oct 8 2025

Updated Aviation Discussion

.KEY MESSAGES...

 - Dry and mild conditions continue through Friday.

 - Windy and unsettled conditions develop this weekend ahead of a
   cold front arriving late Saturday, with increasing
   precipitation chances and lowering snow levels Saturday night.

 - Much cooler temperature Sunday and Monday with additional
   chances for precipitation through early next week.

&&

.DISCUSSION...

 - Meteorological Overview:

Through Friday, a broad upper-level ridge will persist from the
Northern Rockies eastward across the Northern Plains. Meanwhile,
an upper-level trough extending from NW Canada southwestward off
the Pacific NW coast will split, leading to a large closed upper
low developing offshore by Friday. Mild and dry conditions will
continue for the remainder of the workweek under the upper ridge,
with daytime temperatures 10-15 degrees above seasonal averages.
As surface high pressure moves east across the Canadian Prairies,
winds will shift to the north and then east on the plains,
bringing slightly cooler, though still above-average, temperatures
tonight through Thursday.

The offshore upper low will transition into a trough and move
inland late Friday and Saturday. This will lead to increased
southerly flow, bringing windy conditions and an influx of
moisture by Saturday. Precipitation chances will rise late
Saturday with the arrival of a Pacific cold front. There`s
potential for isolated thunderstorms ahead of the front due to
instability, followed by more widespread precipitation as a mid-
level shortwave lifts out of the trough through Sunday morning.

Significantly cooler air will follow the front, with snow levels
dropping and mountain snowfall likely late Saturday night into
Sunday morning. Sunday`s daytime temperatures are expected to
remain in the 40s (around 20 degrees colder than Saturday). Cool
and unsettled conditions, along with additional precipitation
chances (including potential for lower elevation snow), are
anticipated to persist through early next week as more energy
enters the trough. However, there is considerable uncertainty in
ensemble solutions regarding the trough`s evolution next week.

 - Forecast Confidence & Scenarios:

Windy conditions are expected Saturday through Saturday night in
mixed southerly flow preceding the frontal passage, followed by a
westerly flow. Most areas have a 40-60% chance of wind gusts
exceeding 40 mph. However, areas along and near the Rocky Mountain
Front, including much of Glacier County, have a greater than 80%
chance of similar winds, with a 40-60% probability of gusts
surpassing 50 mph.

Atmospheric moisture levels (PWATs) are expected to be unusually
higharound 200% of normalon Saturday and Saturday night. This
increased moisture will be available to interact with the cold
front and frontal wave arriving Saturday/Saturday night. The exact
location of this interaction is still uncertain, but if it
coincides with decreasing snow levels late Saturday night, it
could result in significant mountain snowfall, potentially
affecting some passes. Hoenisch

&&

.AVIATION...
08/12Z TAF Period

VFR conditions prevail at all sites through the TAF period under
upper level high pressure with mainly clear skies or just some thin
high clouds. Surface winds turn to the north and northeast later
this afternoon and evening across the north-central MT plains.
Hoenisch

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  73  36  63  37 /   0   0   0   0
CTB  68  34  60  34 /   0   0   0   0
HLN  70  38  68  40 /   0   0   0   0
BZN  69  35  72  38 /   0   0   0   0
WYS  59  25  67  33 /   0   0   0  20
DLN  67  34  71  39 /   0   0   0  10
HVR  72  36  67  39 /   0   0   0   0
LWT  73  39  68  41 /   0   0   0   0

&&

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

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