009
FXUS65 KTFX 250555
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1155 PM MDT Sat Oct 24 2026

.KEY MESSAGES...

 - Patchy fog is expected in Southwestern Montana this morning.

 - Cool (below seasonal-average) temperatures are expected
   through this upcoming work week.

 - There will be periods of precipitation from Monday evening
   through the rest of the work week.


&&

.DISCUSSION...

 - Meteorological Overview:

Today there will be an upper-level ridge over North-central,
Central, and Southwestern Montana. This will allow skies to be clear
with light winds. As a result at some lower-elevation locations
there is the potential for patchy fog to form. See the Forecast
Confidence and Scenarios section for details. Today it will be dry
with well-below normal temperatures across North-central, Central,
and Southwestern Montana. On Monday the upper-level ridge remains
over North-central, Central, and Southwestern Montana. By Monday
evening an upper-level trough begins to move over the area. This
will bring slightly warmer and dry weather to North-central,
Central, and Southwestern Montana through the day on Monday. Monday
evening snow-levels will begin to fall and snow will begin across
the mountains of Southwestern Montana.

On Tuesday the upper-level trough remains over North-central,
Central, and Southwestern Montana. This will bring widespread
precipitation primarily in the form of lower-elevation rain and
Mountain snow. See the Forecast Confidence & Scenarios section for
details. Due to lingering southerly flow temperatures will warm up a
few degrees on Tuesday but remain below seasonal averages. On
Wednesday an upper-level ridge briefly builds in over North-central,
Central, and Southwestern Montana. This will allow warm temperatures
to persist with mostly dry weather. Thursday through Saturday an
upper-level trough returns to North-central, Central, and
Southwestern Montana. This will bring multiple rounds of
precipitation to the area with cooler temperatures. -IG

 - Forecast Confidence & Scenarios:

For fog this morning there is around a 30 - 50% chance along the
Rocky Mountain Front, the lower-elevations of Cascade County, and
the West Yellowstone area. However based on current satellite
imagery and model soundings this is most likely due to low clouds
and not fog. In the Helena and Gallatin Valley there is a low chance
for fog to form this morning as well, which is suggested in some
model soundings. Based on current satellite imagery the Gallatin
Valley and West Yellowstone area have the highest chance for fog
to form out of any of the areas listed above.

For the Monday evening through Tuesday morning system there is a 50 -
80% chance for 4 inches of snow or greater across the higher peaks
of the Madison and Gallatin Mountains. For the Monday evening
through Tuesday morning system there is a 40 - 70% chance for 2
inches of snow at pass-level in the Madison and Gallatin Mountains.
From Monday evening through Tuesday there is a 40 - 80% chance for a
quarter inch of liquid precipitation or greater across Southwestern
Montana. From Monday evening through Tuesday morning across the
Gallatin and Madison River Valleys and the Lewistown area there is
greater than a 60% chance for a tenth of an inch of snow or greater.
On Tuesday across Blaine and Fergus Counties there is a 40 - 60%
chance for a quarter inch of total liquid precipitation or greater.
-IG

&&

.AVIATION...
25/06Z TAF Period

The main weather concern over the next day or so will be the
potential for low clouds and fog. Southwest MT has the best chance
for seeing fog, as high clouds have moved over much of North
Central MT. Expect the fog to diminish by late morning. Some light
rain/snow showers possible over the northern Rockies today as
well. Mountains/passes will be obscured at times by clouds/fog
through the period. Brusda

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  40  24  38  22 /   0   0   0   0
CTB  41  22  41  20 /   0   0   0   0
HLN  42  23  38  22 /   0   0   0   0
BZN  41  20  45  18 /   0   0   0   0
WYS  45  15  51  17 /   0   0   0   0
DLN  43  24  43  25 /   0   0   0   0
HVR  44  21  46  22 /   0   0   0   0
LWT  41  20  40  23 /   0   0   0   0

&&

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

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