The National Weather Service in Missoula is forecasting two surges of arctic air across Western Montana and the Idaho Panhandle on Friday night, Feb. 27, and again late Monday into Tuesday, March 1 and 2.

“The first surge of cold north to east winds is expected this evening into early Saturday,” NWS said. “Temperatures should fall into the single digits to lower teens for most areas by Saturday morning.  East to northwest winds will increase to 10 to 20 mph with gusts 30 to 40 mph in the more typical windy locations this evening.”

Those stronger winds are expected to bring wind chills down to the zero to 10 below mark in the Flathead, Missoula, Bitterroot, Mission and Tobacco valleys, and 10 to 20 below wind chills from Glacier National Park southward across the Blackfoot River valley to Anaconda and Butte.  

Areas of light snow are expected Friday evening into early Saturday morning across parts of southwest Montana, including Butte, Warm Springs, Anaconda and Lost Trail Pass.

“Although snow amounts should generally be less than one inch, local slick road conditions are still expected to develop,” NWS said.

The second surge of arctic air is expected to arrive in Western Montana by late Monday into Tuesday.  This second surge is expected to bring light snow across most of Western Montana, with 1 to 2 inches possible in the valleys and 3 to 6 inches in the mountains.

“As the colder air arrives late Monday, there should be areas of blowing and drifting snow, especially from the Missoula and Flathead valleys eastward to the Continental Divide,” NWS said. “In addition, the second surge appears to be a colder push of arctic air and should translate into bitter cold temperatures and wind chills Monday night into Tuesday.”

The coldest actual air temperatures should take place Monday night and Tuesday night. Significant moderation is possible afterwards, NWS is forecasting.

“Temperatures should plummet to 20 to 30 below normal during the coldest portion,” NWS said.