textproduct: Missoula

DISCUSSION

KEY MESSAGES:

- Noticeably cooler today, but breezy west winds are ushering in thick smoke from regional wildfires.

- Cool morning temperatures Monday and Tuesday.

- A prolonged warming and drying trend this week.

A dry cold front pushed through the Northern Rockies last night, leaving a much cooler air mass in its wake. High temperatures today will top out comfortably in the 70s to low 80s across most local valleys. However, breezy west to northwest winds will persist throughout the day. These continuous winds are pulling in thick smoke from highly active wildland fires across Washington, and smoke conditions will significantly worsen across the region by tonight.

This cooler and drier airmass will persist into early this week. With clear skies and lighter winds expected overnight tonight and Monday night, very efficient radiational cooling is anticipated. High-elevation valleys and typically cold-prone locations are likely to see temperatures drop into the mid-30s by early morning, presenting a chilly start for campers and early-morning recreationists. Some high-resolution models continue to hint at a slight chance for scattered showers overnight into Monday morning across northwest Montana, particularly near the Canadian border and Glacier National Park.

A broad upper-level ridge of high pressure will rebuild across the western United States this week. This pattern shift will initiate a prolonged warming and drying trend across western Montana and north-central Idaho. This system is unlikely to tap into North American Monsoon moisture at least through the end of the week, meaning the atmosphere will remain dry. Expect valley temperatures to climb back into the low to mid-90s by Wednesday and Thursday.

AVIATION

Smoke is the primary aviation hazard over the next 24 to 48 hours. Yesterday's extreme fire behavior across the Pacific Northwest has produced a massive smoke plume that post-frontal west winds are currently funneling directly into Montana. Satellite imagery reveals smoke increasing in northwest Montana. Smoke models have this smoke expanding throughout most of the region tonight, so expect widespread MVFR visibility restrictions by Monday morning. In addition to the smoke, gusty west to northwest wind gusts of 20-25 knots will remain common today. Winds will begin to subside after 03Z this evening. As the week progresses, soaring temperatures will reintroduce high density altitude concerns across all local terminals by mid-week.