BOZEMAN – Temperatures are struggling to warm up in the lower valleys for one reason. Valley inversions are strong. Warmer air is pushing into SW Montana Friday afternoon and that is trapping cold pools down into the lower valleys.
We need a good cold front or stronger valley winds to scrub out the inversion layer and currently that is not happening. If the inversions weaken a little Saturday temperatures could warm up into the upper 30s to lower 40s or near normal but it will take most of the day Saturday to get up there so plan on another cold start in the morning.
Morning lows Friday were well below zero in cold prone valleys like West Yellowstone and Wisdom between -20 to -30 below zero.
The next weather maker will begin to dig into Western Montana Sunday afternoon and that could break the inversion layer for SW Montana. Unfortunately, that will also bring increasing snow Sunday evening into Monday morning.