Area Forecast Discussion

DISCUSSION

KEY MESSAGES:

- Cooler temperatures and periods of valley rain and mountain snow Saturday evening through Monday

- High pressure bringing stable conditions, temperatures slightly above normal through midweek

High pressure and stable conditions have developed over the region. Chances for morning valley fog are small as a weak northeasterly gradient will allow for light winds and valley mixing. These conditions will repeat through Saturday afternoon.

By the time the Pacific low gets inland on Saturday, it will follow a familiar theme and move south, bringing most of its forcing with it. There will, however, be enough moisture and lift for precipitation focused on north-central Idaho and southwest Montana, as well as the mountains along the Continental Divide, on Saturday night through Monday. Snow levels will be around 5000-6000 feet, which would be low enough for a couple inches of snow on Lost Trail Pass and Gilmore Summit by Monday morning.

High pressure builds for midweek, allowing for stable, warm conditions. The stability could mean fog for the Tuesday morning commute in the valleys of western Montana such as the Bitterroot, Missoula, Mission, and Flathead valleys. Ensemble guidance is hinting at more unsettled weather for later next week, but there is still considerable spread in the solutions, so confidence is quite low at this time.

AVIATION

Valley fog in the vicinity of KMSO and KGPI are a possibility this morning, however a weak northeasterly gradient may keep valleys sufficiently mixed up. High pressure will create stable conditions through tomorrow with broken mid to high clouds over the airspace.

MSO WATCHES / WARNINGS / ADVISORIES

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