textproduct: Missoula

DISCUSSION

KEY MESSAGES:

- Unsettled, cool, and showery conditions persist into the weekend.

- Southwest Montana remains very dry but decreasing wind speeds should limit areal extent of critical fire weather.

- Widespread frost and freezing temperatures are highly likely Sunday through Tuesday mornings.

Westerly flow continues over the Northern Rockies today. While conditions remain somewhat breezy, winds are noticeably decreasing compared to the past few days. Expect afternoon gusts generally in the 15 to 25 mph range across the region. In Southwest Montana, very dry air remains in place, however, these decreasing wind speeds will result in elevated but non-critical fire weather conditions.

Elsewhere, a couple weak disturbances continue to move through the prevailing westerlies generating scattered light showers, predominantly focused over north-central Idaho and northwest Montana. Snow levels will continue to hover around 5,000 feet, so light snow accumulations will remain confined to the higher terrain.

A more organized low-pressure system drops into the region over the weekend, enhancing the coverage of precipitation. As the colder air associated with this trough settles in, snow levels will fall to near 4,000 feet by Sunday morning. Minor, slushy impacts are possible over mountain passes through the weekend.

The primary impact of this weekend system will be the unseasonably cold air mass it brings in and leaves behind. Models continue to show high probabilities for widespread temperatures into the frost and freezing ranges (mid-30s and below) for Sunday, Monday, and Tuesday mornings. Anyone with sensitive vegetation or early-season agricultural plantings should prepare to take protective measures.

Looking into next week, ensemble guidance points toward a gradual warming trend. However, the pattern looks to remain slightly unsettled. Scattered showers will remain possible, particularly during afternoon and evening hours.

AVIATION

Scattered light showers are in the forecast particularly in north-central Idaho and northwest Montana. KGPI has the highest probability of seeing some vicinity and light showers. Mountain obscurations will continue to remain a periodic nuisance across the higher terrain. Westerly winds will be lighter than in previous days, though afternoon mixing will still yield gusts of 15 to 20 knots across most terminals persisting into the early evening before decoupling overnight. Note: The KSMN AWOS is currently not transmitting observations properly.

MSO WATCHES/WARNINGS/ADVISORIES

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