Area Forecast Discussion
Issued by NWS Missoula, MT
Issued by NWS Missoula, MT
769 FXUS65 KMSO 171008 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 408 AM MDT Tue Sep 17 2024 .DISCUSSION...Last evening showers and thunderstorms occurred across Idaho County and portions of southwest Montana. The highest observed, one hour total was 0.56" from the Moose Creek RAWS located across the southwestern tip of the Wye Wildfire. One hour radar estimated rainfall of around 0.60" occurred over the Elkhorn Ridge fire, located well south of Red River Hot Spring. Some clearing is expected from eastern Clearwater County, Idaho north and east into northwest Montana this afternoon. This warming combined with elevated moisture will bring more scattered showers and thunderstorms capable of heavy rain from mid-afternoon through late this evening. High resolution models depict the potential for 0.50" to 0.75" an hour rates with the heaviest cores. Two known areas that could be susceptible to flash flooding would be the River Road East Fire burn area southeast of Plains(15% chance) and also the upper portions of the Going-To-The-Sun road(30% chance of occurrence). Of course there could be the potential for mudslide issues near the current wildfire burn scars in these areas. The main upper level low will track into Wyoming tonight, then east and north into eastern Montana on Wednesday. The heaviest wrap-around light to moderate showers will mainly be concentrated along and east of the Divide. Despite this, western Montana will continue to experience persistent showers through Wednesday morning, tapering off west to east into the afternoon hours. Some clearing is expected Wednesday night with high valley locations cooling down into the 30s, and upper 20s in the Dixie, Idaho area. Patchy fog Thursday morning will give way to a gorgeous day across the Northern Rockies with temperatures warming into the 60s and 70s. Breezy westerly winds 10 to 20 mph will develop in the afternoon and evening. Ensemble guidance continue to trend away from the colder system for over the weekend. Looking upstream, the polar jet is quite strong and active, bringing wet systems into southeastern Alaska. Our area may just get clipped by a weather system on Sunday, then there is a chance for a warm-up thereafter with southwest flow. && .AVIATION...Shower and thunderstorm activity will increase in coverage by 17/2100Z(mid-afternoon) and continue through 18/0500Z (10 pm MDT this evening). Locally heavy rain, lower visibility, lightning and gusty winds to 30 knots are possible, especially from Clearwater County, Idaho to areas north and east into northwest Montana. A departing low pressure area will keep persistent showers going through Wednesday. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...None. ID...None. && $$