Area Forecast Discussion
Issued by NWS Missoula, MT
Issued by NWS Missoula, MT
547 FXUS65 KMSO 050709 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 109 AM MDT Fri Jul 5 2024 .UPDATE...Forecast confidence and details in the upcoming prolonged heat wave remains steady. Thus, no changes are necessary to the previous discussion. && .PREV DISCUSSION... /ISSUED 123 PM MDT Thu Jul 4 2024/ DISCUSSION...With some unsettled weather over the Midwest and a massive ridge of high pressure over the eastern Pacific, the Northern Rockies will stay under northwest flow aloft heading into the weekend. The implications will be minor. Expect some increasing northwest winds this evening. Temperatures will gradually increase. A shortwave trough will bring some chances (about 20%) for showers and thunderstorms to northwest Montana on Saturday afternoon. Impactful weather will start later in the weekend as the ridge of high pressure over the eastern Pacific shifts eastward. Confidence is high that a heatwave will affect the Northern Rockies through next week. The middle of next week looks to be the hottest period, with valleys in central Idaho hitting the 100-115 degree range and western Montana valleys reaching 90-105 degrees by next Wednesday (July 10th). Expect nighttime temperatures to cool only into the 50s to 60s, which will make it difficult for those without air conditioning or other means of cooling down to find relief from the heat. As upper level flow transitions back to the southwest later in the week, embedded moisture will bring chances for afternoon thunderstorms by about Thursday. && .AVIATION...High pressure builds today across the Northern Rockies and will remain in place for several days. With a lingering northwesterly breeze, expect most terminals to see an afternoon wind pick up between 05/2100Z and 06/0300Z. && .MSO WATCHES/WARNINGS/ADVISORIES... MT... Excessive Heat Watch from Tuesday afternoon through Friday evening for Kootenai/Cabinet Region...Lower Clark Fork Region. ID...Excessive Heat Watch from Monday afternoon through Friday evening for Northern Clearwater Mountains...Southern Clearwater Mountains. Excessive Heat Warning from noon Tuesday to 11 PM PDT Friday for Orofino/Grangeville Region. Excessive Heat Warning from noon Monday to 11 PM PDT Friday for Lower Hells Canyon/Salmon River Region. && $$