916
FXUS65 KMSO 081856
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
1256 PM MDT Tue Sep 8 2026

.DISCUSSION...

KEY MESSAGES:

-  Rain in northwest Montana diminishes by this evening.

-  A brief drying and warming trend is expected Wednesday and
   Thursday. Fog or low clouds are possible each morning.

-  Chance for frost in high valleys of southwest Montana.

-  Unsettled with showers on Friday. Growing confidence for a wet
   and cool system with high elevation snow developing by this
   weekend


Satellite imagery this afternoon shows a trough of low pressure
moving east over the Continental Divide. This system brought
copious rainfall to much of the Northern Rockies over the Labor
Day weekend. Wraparound moisture from this low will continue to
supply light rain over the Flathead Valley and the Glacier Park
region this afternoon.  Precipitation rates will diminish going
into this evening.

In the wake of the low, upper level flow will turn
northwesterly by Wednesday. As it does, a tightening pressure
gradient and upper level jet streak approaching the Northern
Rockies will bring an increase in westerly winds for Wednesday and
Thursday. Expect choppy conditions on area lakes including
Flathead Lake both days. A broad trough will traverse the
Canadian border on Thursday, pushing a cold front through the
Northern Rockies, further enhancing westerly winds. Drier air
accompanying increase winds will create elevated fire weather
concerns for southwest Montana on Thursday. Daytime high
temperatures for Wednesday and Thursday will bounce back to near
seasonal norms.

More unsettled weather is on the way for the weekend. Model
ensembles are on board for low pressure to return. The broad
trough along the border will bring some chances for precipitation
on Friday, then a secondary, deeper trough arrives on Saturday
through Sunday. While ensemble solutions like the change to
unsettled weather, actual precipitation amounts are still up in
the air. Regardless of precipitation amounts, this system does
look cold enough for precipitation to fall in the form of snow in
the high elevations (7,000 - 8,000 feet), especially along the
Continental Divide including Glacier National Park.



&&

.AVIATION...Rain and low stratus are affecting ceilings and, to a
lesser extent, visibility at KGPI this afternoon. Expect light
rain to continue through the afternoon and diminish this evening.
Low stratus could remain an impact to aviation at KGPI tonight as
the lower atmosphere holds onto quite a bit of moisture from
recent rains. Low clouds will obscure terrain in northwest Montana
this afternoon as well. Elsewhere, high clouds will increase this
afternoon due to wraparound moisture from a departing trough of
low pressure. Clouds decrease tonight. There will be chances for
fog formation at KGPI, and possibly KMSO on Wednesday morning.


&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...None.
&&

$$