BOZEMAN – Unseasonably warm again Wednesday for SW Montana and near record highs are possible today and again on Thursday.
A Pacific storm system with a mostly dry cold front will move into the western half of Montana Thursday. This could produce a few showers from Missoula to Kalispell but not for SW Montana. Locally we will see stronger winds on Thursday and continued above normal temperatures.
The National Weather Service has issued a RED FLAG WARNING for the eastern half of the Beaverhead-Deer Lodge National Forest Thursday noon to 6 pm.
East of I-15 conditions are favorable for new fire starts Thursday. The combination of highs in the upper 60s to lower 70s, near record level heat, relative humidity between 8%-12%, and surface winds sustained between 20 to 30 mph and gusts to or over 40 mph will produce erratic fire weather behavior.
So please use extreme caution with all outdoor activities to avoid accidental new fire starts. South of Dillon the Sourdough Fire has burned around 6000 acres over the last week.
A pattern change is coming this weekend and should help ease the fire conditions across SW Montana. Beginning Saturday a deep trough of Low-pressure will dig into the region producing increasing rain or snow Friday night into Saturday.
A second cold front with a punch of Arctic air will dive rapidly southward Saturday night and could reach southern Montana by Sunday morning. This will help produce widespread snow and gusty winds with much colder temperatures Sunday. Flash freezing of wet roadways is possible and could lead to extremely icy road surfaces Sunday.
Next week several disturbances will overrun the colder air over Montana and will bring several more chances for off-and-on snow showers.
Forecast model averages for possible snow accumulations are in the 2”-6” for Butte to Bozeman and 1”-4” from Dillon to West Yellowstone. Mountains could see over 6” and possibly up to a foot for higher peaks.
Central and Northern Montana could see significant snow accumulations and gusty winds Saturday into Sunday. Early estimates of 6”-12” is possible for valleys from Lewistown to Great Falls and in favored upslope areas along the Rocky Mountain Front could see over a foot of snow.
Forecast model confidence on possible snow accumulations is still preliminary and we will start to fine tune total snow accumulations by the end of the week so look for updates which could vary from the estimates described above.