778
FXUS65 KMSO 091944
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
144 PM MDT Mon Jun 9 2025

.DISCUSSION...

KEY MESSAGES:

-  High pressure will bring near-record daytime high temperatures
   today and Tuesday.

-  Strong storms Tuesday and Wednesday afternoon and evening.

-  Cooler with afternoon showers and thunderstorms through the end
   of the week.


Extreme heat will continue over the Northern Rockies today into
Tuesday causing near daily record readings at many locations. On
Tuesday, the ridge axis shifts to the east causing southwesterly
flow over the Northern Rockies. This flow pattern will allow for
the development of afternoon/evening showers and thunderstorms.
These storms will be scattered in nature with the models
indicating that best placement of storms being over the Glacier NP
and northern Bob Marshall area along with areas south of the
Highway 12 corridor. Any storms that develop on Tuesday afternoon
will be capable of producing gusty erratic winds with the stronger
storms creating gusts up to 50 mph.

This southwesterly flow will persist into Wednesday as two subtle
disturbances move through the region. The first disturbance
appears to traverse southern Idaho county into Lemhi county on
through southwest Montana Wednesday morning causing scattered
showers and maybe an isolated thunderstorm. The second disturbance
will have a similar trajectory as the first, but during the
afternoon hours. This second feature has the potential to kick off
a few more thunderstorms which will be capable of heavy rain,
small hail and gusty winds.

Southwesterly flow aloft remains over the Northern Rockies
Thursday into the weekend. Temperatures are anticipated to remain
cooler compared to the start of the work week, but readings will
still be in the mid 70s into the 80s. These maximum temperatures
will be around 10 degrees above seasonal averages.
Afternoon/evening showers and thunderstorms are expected each day
with the main focus being along the Continental Divide down into
Lemhi county.

&&

.AVIATION...Clear skies and diurnal winds with gusts around
15-20kts are expected this afternoon. The ridge of high pressure
will begin to shift east Tuesday afternoon, allowing the
development of a southwesterly flow pattern. Modest amounts of
moisture and mid-level instability will allow for afternoon
showers and thunderstorm development along the Continental
Divide, potentially impacting KSMN and KBTM between
10/2000Z-11/0200Z.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...Heat Advisory until 9 PM PDT Tuesday for Lower Hells
     Canyon/Salmon River Region...Orofino/Grangeville Region.

&&

$$