MISSOULA - Man, this is some weather, huh?! High pressure is keeping us mostly sunny, dry and very warm... like 20° to almost 30° above average for this time of year across western Montana & in record high territory!
Expect some very big changes midweek, though, as a large trough of low pressure moves onshore in the Pacific Northwest - we're talking a 30° to almost 40° temperature drop from today to Thursday with this one!
Tuesday night, an isolated thunderstorm will be possible across mainly northwest Montana as that next big, weather system arrives otherwise dry and mild.
This sort of two-part wintry system will bring snow to the higher terrain, but could also pose a highly uncertain (yet potentially highly impactful) threat to the valleys.
Right now, look for mountain snow and valley rain/thunderstorms Wednesday with highs 20° to 25° cooler than Tuesday in the mid 50s to low 60s. The NWS says, "48-hour precipitation totals ending Friday morning will favor the mountains of north-central Idaho, the Bitterroot Crest and northwest Montana, where there is a 70% probability of exceeding 1" and a 20% to 40% of exceeding 2". While local rivers and streams will rise, widespread flooding is unlikely at this time. Please stay alert for water pooling on roadways and the potential for small rockslides or debris flows in steep terrain".
Snow levels continue to drop Thursday with most impacts remaining at pass level and above, but some valleys could see a little light snow running into Friday with Friday morning being the best chance for valley snow. Highs Thursday and Friday will be in the mid 40s.
Things look to stay cooler (upper 40s to low 50s) this upcoming weekend with partly cloudy skies.
