Area Forecast Discussion
Issued by NWS Missoula, MT
Issued by NWS Missoula, MT
730 FXUS65 KMSO 181929 AFDMSO Area Forecast Discussion National Weather Service Missoula MT 129 PM MDT Tue Jun 18 2024 .DISCUSSION...A broad trough of low pressure will remain over the Northern Rockies through the rest of the day. Scattered rain showers and isolated thunderstorms will continue to develop and migrate eastward over north-central Idaho and western Montana while under the trough. Brief heavy rainfall and occasional lightning will be the main threats from the convective activity. Clearing skies and light winds tonight into Wednesday morning will allow for areas of frost, mainly from the Mission Valley, south to Lemhi County. Currently, there is a 40-50% probability temperatures could reach 36 degrees or colder for these locations by tomorrow morning. Areas further east (i.e Seeley Lake, Ovando, Anaconda and Butte) are likely to reach freezing, though this isn`t out of the climatological norm for this time of the year. There is high consensus (near 100%) of a warming and drying trend Wednesday through Friday under southwest flow. There is a 20-30% chance of showers or thunderstorms each day, focused mainly along the Divide. This is followed by a brief ridge over the weekend. Under the ridge, daytime temperatures peak about 15 degrees above normal (upper 80s western Montana valleys, low/mid 90s for north- central Idaho). High confidence remains with the brief ridge of high pressure beginning to flatten out early next week, leading to an increase in daily breezes and seasonable temperatures. Some ensemble members (20%), are showing a decent southwesterly flow that would allow for scattered thunderstorms developing in the afternoon and evening hours. && .AVIATION...An upper level trough remains over the region through this evening, leading to periodic showers. Occasional lowered ceilings and visibility reductions will occur with precipitation episodes. Showers greatly diminish after sunset as instability and widespread forcing subsides. Depending on the amount of clearing overnight, frost will be a concern tonight into Wednesday morning across portions of west central Montana and along the Continental Divide. A much quieter weather day, with moderating temperatures and drier conditions, is then expected for the rest of Wednesday. && .MSO WATCHES/WARNINGS/ADVISORIES... MT...None. ID...None. && $$