Mountain Weather

A mild, mostly dry stretch wraps up Thursday and Friday, with valley highs in the 50s and low 60s °F and clouds increasing Friday afternoon. A cold front crosses the region Friday night into Saturday, dropping temperatures 10–15 degrees and bringing snow to the mountains above ~7,000 feet. The storm splits as it crosses Idaho, and sets up for some magical southerly flow (well-known to favor certain areas over others in this region). Air coming from the north out of the Magic Valley is lined up to rise against the Wood River Valley, Boulders, Pioneers, and Sawtooths, squeezing out the most moisture there. Several weather models show this storm could overperform, with some guidance nearly doubling precipitation in favored high terrain, so watch for higher amounts if you're out and about. Sunday falls between storm systems, bringing a short break and slightly warmer temperatures.

Sawtooth & Western Smoky Mountains
Thursday and Friday stay mild, with highs near 50°F in the Stanley area. Saturday is much colder, with highs in the upper 30s °F and snow above about 7,000 feet as southerly flow pushes moisture into the range. Sunday warms slightly into the low 40s °F, and overnight lows run in the low-to-mid 20s °F.
Estimated snowfall: 3–6 inches above 7,000 feet.

Galena Summit & Eastern Mountains
Near Galena Summit, highs are around 50°F Thursday and the low 40s °F Friday, falling to the low 30s °F Saturday. The Boulders and Pioneers are well placed to catch the southerly flow, so Saturday’s snow should be heaviest here. Highs warm into the mid-30s °F Sunday, and overnight lows drop into the low 20s °F.
Estimated snowfall: 4–7 inches above 7,000 feet.

Soldier & Wood River Valley Mountains
Valley temperatures are the warmest in the forecast area, with highs near 60°F Thursday and the mid-50s °F Friday, cooling into the mid-to-upper 40s °F this weekend. Southerly winds will force moisture up into the Wood River Valley and nearby mountains Saturday, bringing 0.20–0.40 inches of water. Expect rain below about 7,000 feet and snow above. Lows will be near 30°F.
Estimated snowfall: 2–4 inches above 7,000 feet.

Banner Summit
Same story: rain in the valleys and snow above about ~7,000 feet. Overnight lows dip into the upper 20s °F this weekend.
Estimated snowfall: 1–3 inches above 7,000 feet.

A more active pattern develops Monday and Tuesday, with colder temperatures expected to follow by midweek.