Polson, Montana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

373
FXUS65 KMSO 120644
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
1244 AM MDT Tue Aug 12 2025

.DISCUSSION...

KEY MESSAGES:

- Summer like conditions through mid week

- Gusty winds and low humidity on Wednesday with increased fire
weather concerns

- Cooler late week into the coming weekend

Very warm and mostly dry conditions will prevail today under westerly flow
aloft. Weak afternoon instability may produce a few virga or light showers
along the Continental Divide. Daytime highs will be 5-10 degrees
above normal.

There are indications of isolated nocturnal showers/thunderstorms
developing late this evening from north-central Idaho into west-
central Montana by early Wednesday as a weak disturbance and
elevated instability move through. On Wednesday afternoon, a
stronger disturbance tracking along the Canadian border will bring
increasing westerly winds, with widespread gusts of 30-40 mph
along with isolated higher gusts. Rain chances will remain
minimal, limited mainly to the Canadian border and the Divide. Low
humidity combined with gusty winds will create elevated fire
weather concerns across the portions of western Montana and north-
central Idaho where fuels are critically dry. Choppy lake
conditions will also be a concern for boaters on Wednesday
afternoon.

A weak, mostly dry cold front will arrive Wednesday night, ushering in
cooler, breezy conditions for Thursday and Friday. Forecast confidence
decreases for the weekend, but ensemble guidance generally supports an
upper-level trough along the Pacific Northwest coast, favoring slightly
below-normal temperatures. Depending on the trough`s depth, scattered
showers and thunderstorms may also develop each day starting late Friday.

&&

.AVIATION...VFR conditions will prevail today through Wednesday. Weak
afternoon instability may produce a few virga or light showers along the
Continental Divide. Westerly surface winds will strengthen this afternoon,
with gusts of 15-25 kts at terminal sites.

Tonight into early Wednesday, a weak disturbance will bring the potential
for isolated nocturnal convection from southern Idaho County into southwest
Montana. On Wednesday, westerly winds will increase significantly
across the area ahead of a weak cold front, with widespread gusts
of 25-35 kts expected in the afternoon.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Fire Weather Watch from Wednesday afternoon through Wednesday
     evening for Flathead Reservation.

     Fire Weather Watch from Wednesday afternoon through Wednesday
     evening for Deerlodge/West Beaverhead...East Beaverhead.

ID...Fire Weather Watch from Wednesday morning through Wednesday
     evening for Palouse/Hells Canyon.

     Heat Advisory from noon to 10 PM PDT Tuesday for Lower Hells
     Canyon/Salmon River Region...Orofino/Grangeville Region.

&&

$$