182
FXUS65 KMSO 071935
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
135 PM MDT Sun Jul 7 2024

.DISCUSSION...Satellite imagery, most notably low-level water
vapor, is showing a high-amplitude ridge of high pressure with its
axis over the West Coast this afternoon. The same imagery product
is indicating a hot and dry airmass under the ridge. The
northwesterly flow that has been over the Northern Rockies will
transition east as high pressure sets in overnight. As high
pressure becomes established, both daytime high temperatures and
overnight lows will creep up, peaking around Wednesday in north-
central Idaho and Thursday for western Montana. Excessive Heat
Warnings and Advisories are in effect for much of Idaho and
Clearwater Counties, as well as the valleys of western Montana.
Although southwest Montana will also see high temperatures, the
duration of the heat wave will be a little shorter there, so there
are no highlights at this time.

High temperatures this week:

-  Central Idaho Valleys...105-112 degrees.
-  Western Montana...Upper 90s to 104 degrees.
-  Southwest Montana...Mid 90s.

Latest guidance is indicating the ridge will flatten on Wednesday
evening. The breakdown of the upper level ridge will bring
increasing west winds gusting to about 20 mph. These winds,
combined with the hot, dry airmass already in place, will create
conditions conducive to wildland fire spread on Thursday.

The Climate Prediction Center is showing a high likelihood
(over 90% chance) for above normal temperatures and dry
conditions persisting through about July 20th.


&&

.AVIATION...Expect mostly clear skies and calm winds at all
terminals over the next 24 hours as high pressure becomes
established over the Northern Rockies.


&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Heat Advisory from 1 PM Tuesday to midnight MDT Friday night for
     Flathead/Mission Valleys...Kootenai/Cabinet Region...Lower
     Clark Fork Region...Missoula/Bitterroot Valleys.

ID...Heat Advisory from noon Tuesday to 11 PM PDT Friday for Northern
     Clearwater Mountains.

     Excessive Heat Warning from noon Tuesday to 11 PM PDT Friday for
     Orofino/Grangeville Region...Southern Clearwater Mountains.

     Excessive Heat Warning from noon Monday to 11 PM PDT Friday for
     Lower Hells Canyon/Salmon River Region.

&&

$$