Area Forecast Discussion
Issued by NWS Missoula, MT
Issued by NWS Missoula, MT
924 FXUS65 KMSO 051943 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 143 PM MDT Fri Jul 5 2024 .DISCUSSION...Satellite imagery this afternoon shows a shortwave trough spinning east of the Continental Divide just north of the border, as well as a high amplitude ridge of high pressure with its axis just off the West Coast. The Northern Rockies is sandwiched between these two features, experiencing northwesterly flow aloft. A shortwave trough embedded in the general flow will move through northwest Montana on Saturday morning, bringing chances for showers (about 30 percent) to that area through about noon and chances for thunderstorms (also about 30 percent) along the Continental Divide on Saturday afternoon. Northwest flow will persist on Sunday as the ridge over the Pacific approaches the Northern Rockies. As it does, temperatures will begin to climb. The ridge axis will become situated over the Pacific Northwest on Monday. Daytime high temperatures will continue to climb and overnight low temperatures will stay elevated, providing little relief at night. The lower Salmon River valley will see triple digits during the day and only into the upper 60s to low 70s at night. Temperatures will continue to rise during the week, peaking around Wednesday in Idaho and Thursday in western Montana. Expect daytime highs of 105 to 115 for the low valleys of Idaho and 95 to 105 for the valleys of western Montana. While the temperatures for any individual day will not be record shattering, the duration of this event is what makes it worthy of attention and respect, as the heat wave will last for most of the week and into the following weekend. && .AVIATION... Expect partly cloudy skies across the Northern Rockies this afternoon and evening. Northwesterly winds gusting to about 20 kt will grace the terminals at KMSO and KBTM. A shortwave trough will bring chances of rain showers (about 30 percent) to KGPI in the morning by about 06/1100Z. && .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. && $$