A weak wave of energy and moisture is moving across western Montana Tuesday evening. There is a slight chance of an isolated sprinkle or shower. Otherwise, partly cloudy overnight with lows in the 40s in Butte and Kalispell to the lower 50s in Missoula and Bozeman.
Drier and warmer air will overspread the area Wednesday and Thursday. We can expect partly to mostly sunny days with near record breaking warmth for early autumn. Highs will warm into the 80s, with the mercury climbing to 90 in some places, including Missoula. Lows in the upper 40s to lower 50s.
A large Pacific storm system will slowly creep into the region Friday through the weekend. There will be a chance of a few afternoon showers and thunderstorms west of the divide, mainly around Missoula and Kalispell. Highs will drop to the 70s. Further cooling will occur this weekend with temperatures dropping below normal. There will be a chance of showers with highs in the 60s. Places like Bozeman and Butte may see highs remain in the upper 50s Sunday and Monday.