266
FXUS65 KMSO 221922
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
122 PM MDT Fri Aug 22 2025

.DISCUSSION...

KEY MESSAGES:

- Increasing chances for locally degraded air quality through the
  weekend due to increased wildfire smoke and stable conditions,
  especially in north central Idaho

- Heat intensifies this weekend, with heat advisories in place for
  lower valleys of north central Idaho

- Increasing chance for thunderstorms early next week as monsoon
  moisture moves northwards from the desert southwest

East winds continue to create breezy conditions across western
Montana, with exposed locations see gusts 25 to 30 mph. Winds may
relax a bit this afternoon, but then will likely increase once
again this evening. East winds will continue into early next week,
but the speeds will decrease through Saturday.

High pressure will strengthen over western Montana and north
central Idaho through the weekend, allowing for temperatures to
warm back into the low to mid 90s for western Montana valleys to
low 100s for the lower valleys of north central Idaho. Heat
advisories have been issued for the lower valleys of Idaho where
hot daytime temperatures coupled with warm overnight temperatures
will cause heat stress, especially to those who are sensitive to
the heat.

In addition to the heat, warm and dry days will allow for
increased fire activity on local/regional wildfires. Anticipate
degraded air quality at times, especially through north central
Idaho valleys and other communities adjacent to wildfire activity.

The warm weather pattern will continue into mid next week.
Forecast models continue indicate monsoon moisture will slowly
drift northwards, possibly reaching Lemhi County by Monday and
into southwest Montana by Tuesday. Thunderstorm activity will
likely ramp up, possibly impacting much of the area by
Wednesday/Thursday time frame.

&&

.AVIATION...Northeast to east winds will continue across all of
western Montana and north central Idaho into Saturday morning.
KGPI and KMSO will feel the brunt of these winds, with gusts to
25 kts possible through roughly 23/0600z. Otherwise, local and
regional wildfire smoke will cause areas of lowered ceiling and
visibility in smoke, obscuring the terrain at times. The lowest
visibilities are currently occurring in north central Idaho,
including at KGIC.


&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...Heat Advisory from noon Saturday to 9 PM PDT Wednesday for Lower
     Hells Canyon/Salmon River Region...Orofino/Grangeville
     Region.

&&

$$