220
FXUS65 KMSO 220955
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
355 AM 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

- Heat this weekend

- Increasing chances for thunderstorms Sunday into early next
  week as monsoonal moisture approaches the region from the
  southwest

Northeasterly winds have developed across northwest Montana this
morning. These easterly to northerly winds will spread across the
Northern Rockies throughout the day today. Temperatures will be
similar to yesterday across western Montana, while north central
Idaho will experience around a 5 degrees warming.

A ridge of high pressure is still expected this weekend and
lasting through much of next week. This ridge will create hot and
dry conditions across the Northern Rockies. The valleys of western
Montana and Lemhi county will be in the upper 80s to mid 90s the
majority of days. As the valleys of Idaho and Clearwater counties
will experience afternoon high temperatures in the 90s to over 100
degrees. Concern still lies on the heat risk of the Orofino to
Riggins region Saturday into Sunday as overnight temperatures
remain quite warm during this hot period. The extent of the
regional smoke will determine if a heat advisory is needed, so
stay tune for further updates.

Monsoonal moisture will be steadily creeping its way northward
into the region Sunday into mid next week. This moisture will
cause high based showers and thunderstorms, causing gusty erratic
winds. The majority of the models keep the moisture limited to
Lemhi county and southwest Montana through the period, but around
35% have the moisture moving up into west central Montana by mid
week.

The long term models are hinting at some sort of ridge break down
by the following weekend, but details are unclear at this time.


&&

.AVIATION...Northeasterly winds have already moved into KGPI this
morning. These winds will steadily spread across the Northern
Rockies throughout the day. Smoke from regional fires will cause
reduced visibility. Lower cloud deck should be anticipated right
along the Continental Divide around Glacier NP through the morning
hours.

&&

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

$$