With a weak La Nina setting up in the Pacific Ocean, the National Weather Service is predicting a colder and snowier winter than normal. LaNina means the ocean currents are a bit colder than normal.
That sets up a blocking high near Alaska that drives cold air down from the arctic, explained National Weather Service meteorologist Bob Nester in a conference call with reporters on Monday.
The winter forecast for Northwest Montana is for more frequent wet weather systems and more arctic air outbreaks than normal. The Canadian border could be particularly snowy.
In essence, the weather pattern could be about what we saw last year, where the snowpack was about 128 percent of average. Temperatures should be about 1 to 3 degrees below normal on average as well.
Winter will get a head start this week, with a winter storm watch issued for Wednesday and Thursday. Nester said Columbia Falls could see a half-foot of snow from the storm and much colder temperatures. The cold weather is expected to last at least into the middle of the month — a stark contrast to the region’s brutally hot and dry summer.
Cold air is expected to spill over the Divide and collide with moist air from the west. Accumulations will be higher in the mountains. Marias Pass could see upwards of a foot of snow. Friday should be snowy and the weekend will see snow showers as well and a second shot of cold air.