BOZEMAN – A crazy weather pattern will impact Montana this holiday weekend.
First comes near record heat on Saturday. Forecast highs are in the upper 80s through mid 90s Saturday afternoon. That will threaten numerous record highs for September 5th.
The heat is lifting up the backside of a High-pressure ridge Friday and Saturday producing the well above normal temperatures, but it will also help wildfire smoke from California and the Pacific NW to drift over Montana. Air quality could worsen Friday and Saturday.
The combination of extreme heat, very low humidity, and afternoon gusty winds has a new FIRE WEATHER WATCH up Saturday afternoon and evening across the southern half Montana. This includes most of SW Montana.
Human caused fires are very likely Saturday. Please use extreme caution recreating and working outdoors Saturday afternoon and evening. As we saw on Wednesday the combination of hot, dry and wind produced numerous new human caused fires that grew out of control.
A pattern change is expected on Sunday and Monday. We could see higher mountain snow Monday into Tuesday. The flow aloft will shift out of the north beginning Sunday with the coldest air reaching the state Monday into Tuesday. Temperatures could fall 30 to 40 degrees from Saturday to Monday.
Higher mountain snow is possible Monday into Tuesday. This will melt off later next week. Accumulations of several inches is possible with heavier snow for the highest peaks.
Forecast lows early next week will fall down around freezing for lower valleys and well below freezing for higher valleys. Forecast highs will drop well below normal by Monday and Tuesday with upper 40s through the upper 50s.