textproduct: Missoula

DISCUSSION

KEY MESSAGES:

- High pressure reaches its maximum strength this afternoon with many valleys reaching the mid-50s to low 60s.

- Rain and mountain snow arrives to the entire region starting Wednesday morning, with a 80%+ chance of measurable precipitation.

- A cold front will sweep through Wednesday night, ushering in gusty westerly winds (30-40 mph) and dropping snow levels to near valley floors by Thursday morning.

The upper-level ridge is centered directly over the Northern Rockies this morning. This will result in afternoon breezes and mostly sunny skies. Highs will soar into the mid-50s and low 60s for most Montana valleys and north-central Idaho.

A transient Pacific trough will move across the region on Wednesday, and rain will expand in coverage from north to south. Initially passes like Lookout are expected to start with rain before transitioning to snow during Wednesday. A cold front will filter cooler air into the region late Wednesday night into Thursday morning. Medium uncertainty remains regarding the exact timing of the cold front Wednesday night. Deterministic models show the trough stretching as it moves south, which could delay the arrival of colder air. If the front is slower, Thursday morning may stay as rain or a rain/snow mix in the valleys; if its faster, we will see a quicker transition to all snow.

Westerly winds will become gusty behind the front. Expect gusts of 30 to 40 mph, particularly along the Continental Divide and through the Butte/Blackfoot region.

The region remains under an unsettled northwest flow pattern for Friday through Monday. Expect hit-or-miss snow showers to persist, primarily focused over the mountains. Breezy conditions will continue, likely peaking again on Sunday.

Long Range: We are still tracking a 30% chance of a colder Arctic system arriving early next week (March 9-11). This remains the primary focus for potential high-impact winter weather in the extended forecast.

AVIATION

VFR conditions will prevail across the region through this afternoon as the upper-level ridge dominates. Ceilings will begin to thicken and lower from the west tonight ahead of the Pacific trough. Expect widespread MVFR conditions to develop at KGPI, KMSO, and KHRF after 1200Z Wednesday as rain and mountain snow move into the Northern Rockies.

MSO WATCHES/WARNINGS/ADVISORIES

MT...None. ID...None.