BOZEMAN – A very active weather pattern change is coming this weekend. Be prepared for colder temperatures, mountain snow, and very strong surface winds.
Ahead of a strong Pacific storm the flow aloft is right out of the SW and this continues to produce warmer than temperatures Friday into Saturday but it also paves the way for thick wildfire smoke mostly from fires in California to lift into SW Montana.
The smoke is so thick it’s hard to see our nearby mountain ranges and once that occurs air quality conditions are worsening. As of 1 pm Friday most air quality ratings are in the “moderate” range with Butte’s rating worse at “Unhealthy for sensitive groups”.
Air quality will continue to be horrible through Friday evening into Saturday but once a strong surface cold front hits Saturday evening it should scrub out the smoke by Sunday.
The next weather maker is a strong Pacific storm system to plow through Montana Saturday afternoon through Sunday morning.
Ahead of this storm look for warm, dry and very windy conditions Saturday. These weather factors have a RED FLAG WARNING up for SW Montana Saturday afternoon into early Saturday evening. Please be very careful with all outdoor activities Saturday to avoid accidental fire starts as small fires can grow quickly out of control.
A WIND ADVISORY is up for the Butte/Blackfoot region from 10 am to 8 pm Saturday. Sustained winds 20 to 30 mph with gusts 40 to 50+ mph is likely. Strong crosswinds will impact I-90 from Butte to Deer Lodge and I-15 in the Butte area.
Although the Butte/Blackfoot region is under an advisory the entire state will see strong winds Saturday so look for additional wind highlights to be issued for Saturday.
This storm will produce scattered valley rain and higher mountain snow for SW Montana late in the day Saturday with a better chance for wet weather Saturday evening into Sunday.
Forecast models are not that impressive for lower valleys total rainfall but the forecast models are aggressive for mountain snow accumulations. Snow levels could fall to 5,000’ by Sunday morning but above 6,000’ will have a better chance for accumulations. Several inches are possible for higher mountain passes in SW Montana and wet roads could turn icy Sunday into Monday.
Temperatures will turn much colder behind the cold front Sunday. Highs could be in the 70s Saturday but only in the 40s and 50s Sunday into Monday.