106
FXUS65 KTFX 130955
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
355 AM MDT Sun Sep 13 2026

.KEY MESSAGES...

- Windy at times today through Monday.

- Increasing chance for showers and thunderstorms this afternoon
  into this evening.

- Cooler afternoon temperatures early this week will give way to
  warmer and drier conditions next weekend.

&&

.DISCUSSION...

 - Meteorological Overview:
A closed upper level low is approaching Montana from the west this
morning. Thus expect increasing clouds this afternoon, along with
increasing chances for showers/thunderstorms by this evening. The
heaviest precipitation will generally fall over North Central MT
tonight. Colder temperatures will also move into the CWA, with the
Glacier Park area seeing the coldest temperatures. Rain will
change to snow for elevations above 6500 feet overnight, with some
snow accumulations at ridge tops. This system exits the CWA on
Monday, with showers decreasing during the afternoon.

Generally dry and stable conditions are expected from Tue through
Thursday, along with a slow warming trend during this period.

On Friday, a quick moving closed upper level low will move from
west to east across Southern MT. This will result in a good chance
for precipitation over Southwest MT by Friday. At this time, most
of the precipitation will fall as rain, and since it will be
quick moving, heavy precipitation is not expected at this time.

Looking ahead to next weekend, generally dry and warm conditions
are expected for next Sat/Sun, as a quick building upper level
ridge of high pressure is forecast to build over the northern
Rockies.

 - Forecast Confidence & Scenarios:
The main concern for later today and tonight will be thunderstorm
potential over the Plains and snow over the Rockies.

The airmass will become unstable by this afternoon, with the HREF
forecasting a strong storm developing between Great Falls and
Havre between 5 PM and 8 PM this evening. Hail and strong wind
gusts will be the main impact from this storm. Additional
thunderstorms are possible a bit further east this evening as the
entire disturbance starts to shift to the east.

Overnight, the concern shifts to the Rocky Mountain Front in terms
of how low do snow levels get by Monday morning. The current
freezing level aloft is near 11,000 feet, so it will take some
time for the air to cool this evening. That being said, by Monday
morning, snow levels could fall down to about 6500 feet over the
Rocky Mountain Front, including the Glacier Park area. Snow
accumulations of a few inches are possible above 7000 feet. No
winter weather advisory for snow will be issued at this time.

There continues to be near a 70 percent chance for strong winds
today from Ennis to Norris Hill. It is looking like sustained
winds for an hour or so might be the bigger impact. Thus a high
wind warning has been issued for this area.

For Monday, there continues to be about a 60 percent chance for
strong winds over Judith Basin and Fergus counties. Thus the high
wind watch over Central MT was expanded to include Judith Basin
County for Monday. Brusda

&&

.AVIATION...
13/12Z TAF Period.

Morning low clouds will give way to increasing chances for
showers/thunderstorms this afternoon and evening. Some storms
could be on the strong side this evening over North Central MT.
Otherwise gusty afternoon winds will decrease for a short time
overnight. Showers decrease during the day on Monday.
Mountains/passes will be obscured at times across the CWA through
the period. Brusda

&&

.FIRE WEATHER...
A red flag warning has been issued for portions of Southwest MT
for low humidity and gusty winds for today. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  68  45  62  41 /  10  70  20   0
CTB  59  41  57  39 /  40  20  40  20
HLN  71  43  63  39 /  20  50  10   0
BZN  78  38  62  33 /   0  70  10   0
WYS  69  26  59  23 /   0  20   0   0
DLN  75  36  63  32 /   0  10   0   0
HVR  71  45  62  39 /   0  90  50  10
LWT  72  40  57  36 /   0  40  30  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
High Wind Watch from Monday morning through Monday afternoon for
Fergus County below 4500ft-Judith Basin County and Judith Gap-
Snowy and Judith Mountains.

High Wind Warning from noon today to 6 PM MDT this evening for
Madison River Valley.

Red Flag Warning for portions of Southwest MT for today.

&&

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