Fog will worsen through weekend
Strong high pressure will continue to dominate Montana's weather through the weekend and beyond.
This will bring pleasant late autumn weather to southwest Montana around Butte and Bozeman. Clear, cold nights and sunny, chilly days through Saturday. Milder early next week. Lows in the single digits in Butte to the 10 in Bozeman. Highs in the 30s through Saturday, with low 30s in Butte and lower 40s in Bozeman by Sunday and next week.
For the valleys west of the divide, cold air will become trapped. Thus, highs only in the 20s. Lows in the 10s to lower 20s. Fog will also form in these areas, including Missoula and Kalispell. The fog may become a major issue by the weekend and next week.
This is a prolonged dry and calm weather pattern.