textproduct: Missoula

DISCUSSION

KEY MESSAGES:

- Very warm start to the week, followed by mild conditions most of the week.

- Break down of the ridge coming next weekend.

- Snow potential coming late next weekend and early next week.

Warm and dry through Friday are the expected conditions, with temperatures at times running 15 to 20 degrees above normal. Today and Tuesday a flattening of the ridge will allow for an uptick in westerly winds.

The ridge rebuilds by Wednesday with stability returning to the valleys and winds becoming terrain driven.

Friday a trough dropping south out of Canada will bring change to the region. There are 2 features of this system that stand out, first a dramatic cool down of at least 20 degrees and potentially more along with very breezy conditions. This system will come from continental Canada and be relatively dry. That said, a few model outcomes depict tropical moisture being pulled into the trough, well south of our region and eventually east of the Divide. Then a mid-level low pressure system spins up wrapping that moisture from east of the divide back into our area. More to come with this system, but the potential exists that after a cooldown of 20 to 30 degrees a period of precipitation develops producing mountain snow.

AVIATION

High pressure is weakening today and Tuesday and will allow for increased breezes. Winds are expected to remain below 20kts today and weaker Tuesday. Each morning sufficient stability will exist to produce patchy valley fog at KGPI and KMSO. Drier air may settle into KMSO by Tuesday morning squashing fog chances.

MSO WATCHES/WARNINGS/ADVISORIES

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