The season’s first widespread winter weather pushes into Montana from Canada on Tuesday and it could create some dicey travel conditions.
Bob Nester is a senior forecaster with the National Weather Service in Missoula.
"It’s expected as early as Tuesday morning, impacting northwest Montana and slowly moving south through the day. The arctic air is going to spill across the divide and impact all of western Montana and central Idaho by the late afternoon/evening hours."
Nester says the system could bring 1 to 3 inches of snow to the valley floors and 4 to 6 inches to the mountains; not a lot, but when combined with the expected gusty winds …
"What that’s going to create is a pretty conducive environment for snow and blowing snow which will be difficult for traffic. Visibility will be less than a mile at times.”
Very localized wind chill temperatures of 10 to 15 below zero by Tuesday evening aren’t out of the question in some areas such as Kalispell’s Badrock Canyon. Missoula’s blustery Hellgate Canyon could also dip from 0 to 10 below by tomorrow night.
West-central Montana’s temperatures may be just warm enough Tuesday afternoon that the snow could initially melt on the roads, but once that arctic air moves in, that slush could quickly freeze.
"That could be a big concern for travel, especially in west central Montana and down through the Missoula and Butte areas, especially along the I-90 corridor, Highway 200 up through Greenough through Seeley Lake."
The Weather Service predicts we’ll have a few particularly cold mornings later this week, but daytime highs should bounce back into the mid 20s under clear and dry skies.
Nester says the El Niño effect is starting to kick in, bringing moisture to parts of California, southern Oregon, Arizona and New Mexico. What does this mean for western Montana? Lots of cold air trapped in our valleys.
"We’re not expecting any major system, so those cold air inversions are not going to break. We might have some stagnant air as we get into later next week.”