452
FXUS65 KTFX 272319
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
519 PM MDT Sun Sep 27 2026

Aviation Section Updated.

.KEY MESSAGES...

 - There will be isolated showers this afternoon and evening with
   showers and thunderstorms in Southwestern Montana Monday
   afternoon/evening.

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

 - Monday through Friday it will warm up to around seasonal
   averages with mostly dry weather.

&&

.DISCUSSION...
/Issued 117 PM MDT Sun Sep 27 2026/

 - Meteorological Overview:

This afternoon an upper-level ridge begins to build in over North-
central, Central, and Southwestern Montana. This will keep cool
temperatures over the area. An upper-level shortwave will move
through the upper-level flow this afternoon and evening and bring
showers and thunderstorms to Southwestern Montana. This evening
isolated showers will spread to North-central Montana. On Monday a
weak upper-level trough moves over North-central, Central, and
Southwestern Montana. This will bring showers and thunderstorms to
Southwestern Montana on Monday. It will warm up across the area with
mostly dry weather north of I-90 on Monday.

On Tuesday there will be zonal (west to east) flow over North-
central, Central, and Southwestern Montana. This will allow warm
temperatures to remain with dry weather. On Tuesday there will be
strong low-level and mid-level winds. This will bring windy
conditions to North-central Montana with the strongest winds along
the Rocky Mountain Front. On Wednesday zonal flow remains over
North-central, Central, and Southwestern Montana with strong low-
level and mid-level winds. This will bring warm and mostly dry
weather to the area with windy conditons across North-central
Montana. On Thursday and Friday an upper-level ridge builds in
over North-central, Central, and Southwestern Montana. This will
allow temperatures to warm up with mostly dry weather across the
area. -IG


 - Forecast Confidence & Scenarios:

On Monday there is a 20 - 30% chance for thunderstorms across
southern Gallatin and Madison Counties. On Monday there is a 40 -
60% chance for a quarter inch of rain or greater in the West
Yellowstone area. On Tuesday across the Northern Rocky Mountain
Front there is a 40 - 70% chance for wind gusts of 75 mph or
greater. On Tuesday across the plains west of I-15 there is a a 20 -
50% chance for wind gusts of 55 mph or greater. As a result a High
Wind Watch was issued for the northern Rocky Mountain Front and
northern High Plains from 12 AM Tuesday to 12 AM Wednesday. -IG

&&

.AVIATION...
28/00Z TAF Period.

An elongated Pacific trough will bring variable cloudiness and
scattered showers/light stratiform rain tonight into Monday. The
most widespread precipitation and low VFR/MVFR flight degradations
will be south of the I90 corridor roughly between 28/08 and 28/16Z,
especially for the KWYS area. - RCG

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  45  73  45  73 /  30   0   0   0
CTB  36  67  42  65 /  10   0   0   0
HLN  42  71  40  74 /  20   0   0   0
BZN  38  68  37  74 /  10  20   0   0
WYS  37  60  28  66 /  70  50  20   0
DLN  40  68  36  75 /  10   0   0   0
HVR  41  72  42  75 /  20   0   0   0
LWT  41  70  41  76 /  10  10   0   0

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
High Wind Watch from late Monday night through Tuesday evening
for East Glacier Park Region-Northern High Plains.

&&

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