Area Forecast Discussion
Issued by NWS Missoula, MT
Issued by NWS Missoula, MT
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. && $$