A winter weather advisory is in effect for all of Western and West Central Montana through Friday at 9 a.m.

National Weather Service forecaster Bob Nestor says the Missoula and Bitterroot valleys could see anywhere from 1 to 4 inches of snow through Friday. The main reason for the advisory is that Thursday's rain has frozen with a light layer of snow, causing very slick road conditions in some areas.

Nestor says strong winds in the Hellgate Canyon and into downtown Missoula could cause whiteout conditions through Friday.

Nestor says Southwest Montana could see several feet of snow, and then bitter cold temperatures, targeting mostly the areas from Butte to Dillon.

There is also an avalanche warning for Southwest Montana.

National Weather Service Forecaster Bob Nestor