Area Forecast Discussion
Issued by NWS Missoula, MT
Issued by NWS Missoula, MT
489 FXUS65 KMSO 181813 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 1213 PM MDT Wed Sep 18 2024 .DISCUSSION...The low pressure system that brought widespread beneficial rainfall to the region, has moved into eastern Montana this afternoon. Cool temperatures with mostly cloudy conditions will be the result for the rest of the day. A mostly dry west to northwest flow will develop over the Northern Rockies for the rest of the week and weekend. A weak ripple in the flow Friday will aide in an increase in westerly winds during the afternoon, with a 60-70% probability for gusts reaching 20 mph throughout western Montana and north-central Idaho. Those probabilities lower to 30-40% for widespread gusts of 25 mph. Those planing to recreate on Flathead Lake Friday afternoon between 3PM and 9PM should keep that in mind. The increase in wind Friday will also help with drying of the atmosphere and with partial clearing skies during the overnight hours, there will be increasing probabilities for areas of frost both Saturday and Sunday mornings. As it stands now, widespread frost probabilities are higher (30-40%) Sunday morning for the more populated valleys of western Montana. As for north-central Idaho, those outside of the higher elevated valleys (Orofino, Kamiah, & Grangeville) the probability for frost is less than 10%. All the ensemble clusters depict a weak shortwave trough by Monday, that will bring a general 20 to 30 percent chance for showers. Temperatures will be seasonable to start the week, then a gradual warm-up ensues mid-week, with 85% of the clusters showing a ridge of higher pressure with dry conditions. && .AVIATION... As the upper low departs, skies will gradually clear tonight allowing for patchy fog in the valleys lasting into Thursday morning. Otherwise, VFR conditions will be common on Thursday with afternoon gusts of 15-20 kts at terminal sites. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...None. ID...None. && $$