Valley inversions strengthen this week
A very calm, tranquil weather pattern is developing across western Montana as strong high pressure slowly moves into the region from the west.
We are on the east side of it now, so a moist north northwest flow will bring a few more clouds through western Montana Tuesday evening. Drier air in the mid and upper levels will decrease cloud cover by Wednesday morning. There will be a chance of some patchy fog. Lows in the single digits around Butte to the 10s elsewhere. Partly to mostly sunny Wednesday with highs in the upper 20s to lower 30s.
Fog will become a major concern the rest of the week and weekend. The core of the high will settle over the region. While temperatures will be milder in the mountains and east of the divide around Bozeman, cold air will become trapped in the valleys around Missoula and Kalispell. While most of Montana will enjoy sunshine, fog and stratus clouds will develop with the inversions.
Highs will warm to the lower 40s in the Bozeman area by Friday while highs remain in the 20s with the inversions in the Missoula and Kalispell areas.
More of the same is expected this weekend into next week as the stagnant weather pattern continues.