847
FXUS65 KTFX 041435
AFDTFX

Area Forecast Discussion
National Weather Service Great Falls MT
835 AM MDT Thu Sep 4 2025

.KEY MESSAGES...

 - Gusty north winds today following the passage of cold front.

 - Areas of degraded air quality from wildfire smoke early today
   with improvement later today and tonight.

 - Cooler temperatures through Friday before warming above average
   again this weekend.

&&

.UPDATE...

The cold front will continue to advance south throughout the day.
Gusty winds will accompany the front. Though the strongest winds
will be in eastern Blaine/Fergus Counties where the front has been
mixing down stronger winds from the low level jet. Hi-res models
have been consistent in having this wave of smoke along the front
travel south with it, which should help clear out a good chunk of
smoke across North-Central MT. There`s a low chance (<20%) for a
few sprinkles along the front. However, high cloud bases are
giving low confidence precipitation reaches to the ground.
-Wilson

&&

.DISCUSSION...
/Issued 436 AM MDT Thu Sep 4 2025/

 - Meteorological Overview:

A highly amplified upper level pattern remains in place with a sharp
ridge extending north through BC and broad/deep trough extending
from central Canada into the eastern US. A shortwave trough and
clipper-type surface low diving southeast around the trough out of
SK will drag a cold front south across the border this morning with
surface high pressure building east of the Canadian Rockies sliding
south in the wake from front later today and tonight.

Hi-resolution models (HRRR/RRFS) continue to depict a higher
concentration of smoke to spread south along with the front this
morning. Gusty north winds develop from north to south following the
frontal passage with gusts in excess of 30 mph most
likely/persistent through this afternoon across far eastern
portions of north-central MT as well as through the N-S oriented
valleys of SW MT, sustained by surface high pressure building
southward. Gusty N winds may persist into this evening through
some SW MT valleys while winds diminish rather quickly this
evening across north-central MT. A period of lower clouds and
possibly even some sprinkles of rain may develop in northerly
upslope favored locations (Rocky Mtn Front and N-slopes of the
Little Belts) following the frontal passage.

The cooler airmass maintains temperatures near to somewhat below
seasonal averages across the area through Friday before a much
less amplified upper level ridge shifts east into the Northern
Rockies this weekend, pushing temperatures back above average. As
the ridge axis shifts east across MT later this weeekend into
early next week, moisture will begin to feed back into the region
ahead of upper level troughing moving toward the west coast for an
increasing risk of afternoon/evening showers and thunderstorms,
initially across portions of SW MT this weekend before expanding
across much of the area through early next week.

 - Forecast Confidence & Scenarios:

Early morning observations in southern AB show visibility generally
in the 3-6SM range with moderate to unhealthy air quality ratings. A
several hr window of similar conditions is possible across portions
of the N-central and SW MT this morning. Cleaner air will eventually
spread south later this afternoon and evening, bringing improvement
to much of north-central and central MT with lower confidence in
improvements to smoke impacts across areas further south across SW MT.

Clearing skies and light winds tonight will allow temps to fall to
within a few degrees of 40F for many locations. While not far from
seasonal averages for early September (generally in the mid 40s),
this would be the coolest overnight night minimums for many locations
since mid June. Hoenisch

&&

.AVIATION...
04/12Z TAF Period.

Gusty north winds develop from north to south across north-central
and eventually southwest MT this morning as a cold front moves
across the area. Regional wildfire smoke will maintain degraded
slant-range visibility with a period of more concentrated smoke
potentially producing some MVFR visibility reductions this
morning, primarily across north-central MT. Some lower clouds may
develop along the Rocky Mtn Front and Little Belts for a period
following the frontal passage this morning with little or no
impact to area terminals. Skies clear with decreasing winds this
evening. Hoenisch

Refer to weather.gov/zlc for more detailed regional aviation
weather and hazard information.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  68  41  72  40 /  10   0   0   0
CTB  66  37  71  38 /   0   0   0   0
HLN  72  44  76  45 /   0   0   0   0
BZN  77  39  75  39 /   0   0   0   0
WYS  77  34  73  32 /   0   0   0   0
DLN  77  41  75  42 /   0   0   0   0
HVR  68  39  68  39 /   0   0   0   0
LWT  64  37  67  38 /  10   0   0   0

&&

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

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