A winter weather advisory for the Missoula and Bitterroot valleys will virtually assure the area a white Christmas, as three to five inches of snow are expected between Friday afternoon December 20 and Saturday morning, December 21.

National Weather Service forecaster Corby Dickerson said on Friday morning that a moist pacific system will arrive this afternoon bringing snow to the western Montana valleys.

"Right now, we're looking at the three to four inch range total, starting late this afternoon and continuing through tomorrow morning," Dickerson said. "Unfortunately, the heaviest snowfall is expected to arrive during the evening commute."

Dickerson said heavy snow is expected in the mountains, with lighter amounts in the valleys.

"Lolo Pass looks to get at least a foot or maybe more," Dickerson said. "A lot of the areas in central Idaho are looking at getting even more snow, but for us here in the Missoula valley, it'll be in the three to four inch range overall. It might vary a little bit as it usually does across the valley."

The winter weather advisory is expected to last until 11 a.m. on Saturday, December 21.

National Weather Service Forecaster Corby Dickerson