485
FXUS65 KMSO 210944
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
344 AM MDT Thu Aug 21 2025

.DISCUSSION...

KEY MESSAGES:

- Heat this weekend

- Chances for thunderstorms Sunday and Monday for southwest
  Montana and Lemhi County


Seasonal conditions are expected across the Northern Rockies today
along with hazy to smoky conditions to fires throughout the
region. An easterly wind is still expected to move into northwest
Montana tonight. On Friday these easterly to northeasterly winds
will spread across the remainder of the Northern Rockies.

A strong ridge of high pressure will build over the Northern
Rockies on Saturday. Most ensemble solutions are in good agreement
that this will be a prolonged period of high pressure, lasting
well into next week. Daytime high temperatures will rise to about
5-10 degrees above normal for Saturday. The lower valleys of
western Montana will reach the upper 80s to low 90s, while the
lower Salmon and Clearwater valleys will see triple digits.
Monsoonal moisture will make its way into the southern portion of
the Northern Rockies on Sunday as a Four Corners high strengthens
through the weekend. Available moisture will bring chances for
thunderstorms to north-central Idaho and southwest Montana on
Sunday and Monday.

&&

.AVIATION...Fair flying conditions are expected with the exception
of impacts from smoke of local fires. KSMN will continue to
experience reduced visibility due to smoke. While KHRF is
reporting a ceiling from smoke, but during the afternoon the smoke
could potentially mix down to the surface. Multiple fires are
burning within the vicinity of KMSO.

&&

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

$$