textproduct: Missoula

DISCUSSION

KEY MESSAGES:

- Showery conditions through Wednesday

- Warming and drying trend begins Thursday

A steady northwesterly wind pattern aloft will remain over the Northern Rockies through the middle of the week, acting as a conveyor belt for moisture and energy. This setup is ideal for producing scattered showers, particularly during the peak heating of the afternoon and early evening. Recent high-resolution weather models have consistently increased projected rainfall amounts, suggesting widespread shower activity across western Montana and north-central Idaho today. There is enough atmospheric energy to support isolated thunderstorms this afternoon, though the primary threat remains rain. Small disturbances moving through the flow will keep light showers lingering overnight, especially across northwest Montana.

While afternoon temperatures will trend warmer each day, overnight lows will still hover near freezing in most valley locations. The exception will be the lower-elevation valleys in Idaho and Clearwater counties, which should stay in the upper 30s to low 40s. This gradual warming will push snow levels higher over the next 48 hours, limiting travel impacts to the higher mountain passes along the Continental Divide, primarily during the late night and early morning hours. Valley fog will also be possible each morning for locations that see periods of clearing.

High pressure will build over the region by Thursday, bringing a more significant warming and drying trend that will push temperatures above seasonal averages. On Friday, a weak system brushing the Canadian border may increase cloud cover and bring a few light showers to far northwest Montana, but the overall warmth will persist.

By the weekend, long-range models agree on a low-pressure system dropping south along the West Coast and settling into the Great Basin by early next week. While uncertainty remains regarding its exact track, virtually all forecast models now show that this system will stay far enough south to limit impacts in our area to occasional showers. Temperatures are expected to remain high enough to keep snow levels well above the valley floors through the beginning of next week.

AVIATION

Persistent northwesterly flow aloft will maintain a moist and unstable environment across western Montana and north central Idaho, leading to widespread shower activity and localized aviation impacts. Expect VFR conditions to dominate, though periodic reductions to MVFR/IFR are likely this afternoon and evening due to rain showers and isolated thunderstorms, particularly across western Montana terminals (KMSO, KGPI, KBTM). Mountain obscurations will be common as snow levels hover near 5,000 to 6,000 feet, potentially impacting the higher terrain along the Continental Divide. Overnight, as shower activity becomes more isolated, the primary concern shifts to localized valley fog and low stratus, especially in areas that experience clearing and have high boundary-layer moisture from recent rainfall. Surface winds will generally remain light this morning, turning west to northwesterly with gusts of 15 to 20 kts possible by afternoon.

MSO WATCHES/WARNINGS/ADVISORIES

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