More snow and cold forecasted for Northwest Montana

The National Weather Service in Missoula is forecasting mountain snow and a valley rain to snow transition on Wednesday through Thursday morning, Dec. 24-25, followed by another winter storm this weekend.

Periods of mountain snow beginning over Northwest Montana on Wednesday morning are forecasted, then becoming widespread and transitioning southeastward reaching the southern Bitterroot and Lemhi ranges by late Wednesday afternoon.

“A weather disturbance and associated cold front will push into far Northwest Montana on Wednesday morning and proceed southeastward through the region into early Thursday bringing a variety of wintry weather,” NWS said.

Snow will continue overnight, then decrease Thursday morning from north to south. Potential mountain pass accumulations include 5-10 inches for Lookout, Lolo and Lost Trail passes, 3-6 inches for Homestake, MacDonald and Marias passes, with 2-4 inches for Gilmore and White Bird passes.

The forecast for the valleys is a rain or snow mix over Northwest Montana on Wednesday morning or afternoon changing to all snow by late Wednesday afternoon. That will be followed by a rain to snow transition for the valleys of north-central Idaho and west-central and southwest Montana by late Wednesday evening into very early Thursday morning. General valley snow accumulations of 1-3 inches are forecasted, possibly higher in the Seeley Lake area.

There is a potential for light freezing rain in the narrow valleys of Northwest Montana by Wednesday morning, including along U.S. 2 and Highway 200.

“Light rain across Northwest Montana on Wednesday may initially begin as freezing rain for some of the lower valley locations as temperatures will likely be near or just below freezing, but ice accumulations are expected to remain rather light,” NWS said.

Precipitation is expected to gradually proceed southeastward through the day, with valleys changing from rain to snow behind the cold front passage.

“It is also worth noting that temperatures are only expected to fall into the 20s behind the cold front across most areas, so this is not a significantly cold weather system,” NWS said. “Across the mountains, snow levels are expected to remain below mountain pass levels for this event leading to periods of snowfall and difficult travel conditions at times at the higher elevations.”

NWS expects another weather system capable of both mountain and valley snow to move into Northwest Montana on Saturday into Sunday.

“While exact amounts remain somewhat a question, roadways will likely be impacted by another round of accumulating snow for the weekend travel period,” NWS said. “In addition, there is some indication significantly colder temperatures could develop Sunday into Monday.”