Big Sky Resort

000
FXUS65 KTFX 211710
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
1110 AM MDT Wed Oct 21 2026

Aviation Section Updated.

.KEY MESSAGES...

 - It will be mostly dry across North-central, Central, and 
   Southwestern Montana through the day on Thursday.

 - It will be windy across North-central Montana on Friday.

 - Widespread precipitation returns late Thursday through Friday.

 - Temperatures will be well-above seasonal averages through Thursday 
   with temperatures cooling down Friday through this weekend.


&&

.DISCUSSION...
/Issued 501 AM MDT Wed Oct 21 2026/ 

 - Meteorological Overview:

Today over Southwestern Montana there remains Southwest flow aloft 
with weak zonal flow (west-east) over North-central, and Central 
Montana. Due to slightly stronger warm air advection today 
temperatures will rebound to above seasonal averages. Across North-
central and Central Montana it will be dry with a low chance for 
showers across Southwestern Montana today. See the Forecast 
Confidence & Scenarios Section for details. On Thursday there 
remains southerly flow aloft and an upper-level trough associated 
with a Pacific Cold front begins to move over North-central, 
Central, and Southwestern Montana by Thursday evening. This will 
allow temperatures to remain above seasonal averages with mostly dry 
weather until Thursday evening. Thursday evening into Friday morning 
precipitation will gradually spread over North-central, Central, and 
Southwestern Montana. 

On Friday the upper-level trough merges with a shortwave trough 
moving south from Canada. This combined with the cold front that 
moved through will bring widespread precipitation and cooler 
temperatures (below seasonal averages) to the area. Due to the 
cold front that moved through Thursday evening into Friday morning
snow-levels will lower and the precipitation that falls in 
mountain areas on Friday will transition from rain to snow by 
Friday evening. On Friday there is an increasing pressure gradient
and strong low-level and mid-level winds. This will bring windy 
conditions to North-central Montana on Friday. On Saturday an 
upper-level ridge begins to build in over North-central, Central, 
and Southwestern Montana. This will allow the area to dry out with
cool temperatures lingering. 

On Sunday the upper-level ridge remains over North-central, Central, 
and Southwestern Montana. This will keep dry and cool (below 
seasonal averages) weather for the area on Sunday. Monday through 
Tuesday an upper-level trough moves over North-central, Central, 
and Southwestern Montana. This will bring cooler temperatures and
widespread precipitation to the area on Monday and Tuesday. -IG

 - Forecast Confidence & Scenarios:

Today across Southwestern Montana along the Idaho/Montana Border 
there is a 10% chance for a tenth of rain or greater. On Friday 
there is a 40 - 65% chance for wind gusts of 45 mph or greater 
across much of North-central Montana. On Friday along the Rocky 
Mountain Front and plains west of I-15 there is a 30 - 50% chance 
for wind gusts of 55 mph or greater. 

For total liquid precipitation Thursday night through Friday night 
there is greater than an 80% chance for one half inch of liquid 
precipitation or greater along and south of the Montana Highway 
200/US Highway 87 Corridor between Great Falls and Lewistown. For 
total liquid precipitation Thursday night through Friday night there 
is a 30 - 60% chance for one half inch of liquid precipitation 
across North-central Montana north of the Montana Highway 200/US 
Highway 87 Corridor between Great Falls and Lewistown. For total 
liquid precipitation Thursday night through Friday night there is a 
60 - 90% chance for one inch of liquid precipitation or greater 
across Central and Southwestern Montana. Across most of the 
mountains of North-central, Central, and Southwestern Montana there 
is greater than a 60% chance for 2 inches of snow or greater from 
Thursday night through Friday night. Thursday night through 
Friday night there is a 50 - 80% chance for 4 inches of snow or 
greater across the Madison and Gallatin ranges and the Little 
Belts. Friday afternoon into early Saturday morning there is a 
high chance that at least some lower-elevation locations across 
North-central, Central, and Southwestern Montana will see a few 
flakes of snow. -IG


&&

.AVIATION...
21/18Z TAF Period 

VFR conditions will continue at all terminals during this TAF
period. Generally, cloud cover will be limited to a few high level
clouds and winds will be mild. However, KWYS is expected to have 
a period of increased mid-level cloud cover between 0900-1600Z.
-ESH

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  45  74  42  50 /   0   0  30 100 
CTB  39  70  38  46 /   0   0  60  90 
HLN  39  71  43  51 /  10   0  40 100 
BZN  38  70  40  51 /   0   0  30 100 
WYS  29  62  32  46 /  10  10  70 100 
DLN  38  66  41  48 /  10   0  80 100 
HVR  37  73  40  55 /   0   0  20 100 
LWT  45  75  43  52 /   0   0  20 100 

&&

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

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