Windham, Montana Weather Forecast Discussion

735
FXUS65 KTFX 211147
AFDTFX
Area Forecast Discussion
National Weather Service Great Falls MT
547 AM MDT Sun Sep 21 2025
Aviation Section Updated.
.KEY MESSAGES...
- It will be windy today with the strongest winds along the Rocky
   Mountain Front.
- This afternoon through Monday morning showers will spread
   across the area from southwest to northeast.
&&
.DISCUSSION...
/Issued 224 AM MDT Sun Sep 21 2025/
- Meteorological Overview:
Today there will be an upper-level ridge over North-central,
Central, and Southwestern Montana before a cold front associated
with an upper-level trough pushes southeast through North-central,
Central, and Southwestern Montana this afternoon through this
evening. Due a strong surface pressure gradient and strong mid and
upper-level winds combined with the cold front it will be windy
across the area today. It will be the windiest across North-central
Montana with the strongest winds along the Rocky Mountain Front and
adjacent plains. Due to the approaching upper-level trough rain
showers will begin in Southwestern Montana this afternoon and spread
northeast to North-central Montana by this evening. Due to upper-
level and surface temperatures cooling behind the cold front snow-
levels across Southwestern Montana will lower this evening through
tonight. This will bring light snow to mountain peaks in
Southwestern Montana tonight.
On Monday the upper-level trough remains over North-central,
Central, and Southwestern Montana. This will bring cooler
temperatures (near seasonal averages) to the area on Monday. Rain
showers will linger across portions of the lower-elevations of
North-central, Central, and Southwestern Montana Monday morning
with snow showers lingering across some of the mountain peaks in
Southwestern Montana on Monday morning. On Tuesday an upper-level
ridge moves over North-central, Central, and Southwestern Montana.
This will dry out the area and allow temperatures to warm up to
slightly above seasonal averages. On Wednesday the upper-level
ridge remains over North-central, Central, and Southwestern
Montana which will allow temperatures to warm up to well above
seasonal averages with dry weather. Thursday through Saturday an
upper-level ridge will remain over North-central, Central, and
Southwestern Montana. This will bring warm and dry weather to the
area Thursday through Saturday. -IG
- Forecast Confidence & Scenarios:
Today there is a 50 - 80% chance for wind gusts of 45 mph or greater
along the Rocky Mountain Front and adjacent plains. Across the rest
of North-central, Central, and Southwestern Montana there is a 30 -
60% chance for winds gusts of 35 mph or greater today. This
afternoon through Monday morning there is a 35 - 45% chance for a
quarter inch of rain or greater across the lower-elevations of
Central and Southwestern Montana. Across the mountains of
Southwestern Montana there is a 45 - 65% chance for a quarter inch
of liquid precipitation or greater this afternoon through Monday
morning. Across the mountain peaks of Southwestern Montana there is
a 30 - 60% chance for a tenth of an inch of snow or greater between
this afternoon and Monday morning. Today there is a 20 - 40% chance
for a thunderstorm across Central and Southwestern Montana with the
highest probability in Southwestern Montana.
There is high confidence in this forecast through Wednesday.
Thursday through Saturday there remains some uncertainty in the
upper-level pattern as shown in differences between ensemble
clusters and deterministic models. Each day Thursday through
Saturday one of the four ensemble clusters has the upper-level ridge
breaking down and being replaced by a upper-level trough over North-
central, Central, and Southwestern Montana while the other three
ensemble clusters have the upper-level ridge remaining over the
area. The upper-level ridge breaking down scenario would bring
cooler, wetter, and windier weather than the upper-level ridge
remaining over the area scenario. -IG
&&
.AVIATION...
21/12Z TAF Period
While primarily VFR conditions are expected today, SHRA and a few
TSRA across Southwestern Montana will bring brief reductions in
ceilings and visibility, mainly around KEKS, KBZN, and KWYS
(though a passing SHRA can`t be ruled out anywhere). Winds will be
the other major concern today, with wind gusts across the plains
exceeding 20 kts (with gusts to near 35 kts possible at KCTB).
Winds weaken a bit after sunset. Ludwig
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF  84  47  67  41 /  20  60  10   0
CTB  75  44  67  39 /  20  30  10   0
HLN  80  46  67  41 /  30  70  10   0
BZN  79  44  62  36 /  30  90  30   0
WYS  65  36  57  25 /  60  90  60   0
DLN  76  40  63  34 /  50  80  10   0
HVR  85  49  68  41 /   0  60  20   0
LWT  82  46  61  39 /  10  80  40   0
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
http://www.weather.gov/greatfalls

NWS TFX Office Area Forecast Discussion