A high-impact winter storm is expected to hit Northwest Montana over the weekend, the National Weather Service said.

The winter weather system will bring with it the coldest temperatures and wind chills seen in the Flathead so far this season, according to Jeff Kitsmiller and Luke Robinson of the National Weather Service, who led an online press conference Friday afternoon.

With low temperatures dipping below zero in many valley locations, combined with 30 mph gusts, wind chills are expected to be as cold as 25 to 30 degrees below zero by Monday morning.

A minus-30 wind-chill temperature is expected in the North Valley area stretching from Olney to Coram, with a wind-chill of minus 36 forecast for Essex and Marias Pass. Less of a wind-chill factor is predicted in the southern reaches of Flathead County, with a wind-chill temperature of minus 18 expected in Bigfork Monday morning, and minus 15 in Lakeside, according to the National Weather Service.

The system creeping down from Canada likely will begin to drop mixed precipitation over the Flathead Valley early Saturday morning. The forecast shows a slightly warmer spell midday on Saturday before the larger arctic front moves in Saturday night, dropping a mix of rain, freezing rain and snow.

Beginning early Sunday, a widespread strong east/northeast wind will crash into the valley, with gusts reaching speeds of 30 to 40 mph or more in the Flathead. Resulting wind chill could bring temperatures down to around 30 below on Sunday and Monday.

“This is some of the coldest air that we’ve seen this season,” the presenters said.

They expected Saturday’s mixed precipitation to transition into all snow on Sunday, with potential for blowing snow.

The National Weather Service forecasts an overall snow accumulation of around 3 to 5 inches in the valley by Monday morning.

Temperatures will likely bottom out across Northwest Montana on Monday and remain in the single digits at their highest in the Flathead throughout the rest of next week.

Areas farther south toward Missoula and over to Butte likely will see less snow accumulation, slightly higher temperatures and less severe winds.

Kitsmiller and Robinson warned that accumulations of mixed precipitation Saturday and Sunday combined with below freezing temperatures and blowing snow Sunday and Monday have the potential to create hazardous travel conditions.

The low temperatures expected, they said, can be especially dangerous for anyone stranded on the road because of their potential to cause frostbite on exposed skin in 5 to 10 minutes.

The approaching winter weather, presenters said, is related to the weather system currently impacting much of the Midwest, but is not the exact same system.

This system, they said, had to work its way south from Canada, but it’s the “same related cold that’s been sitting up north that’s just been waiting to come down and get us.”

A winter storm watch was issued on Friday for most of Northwest Montana, from Eureka down to Butte and from Thompson Falls over to Lincoln.

For more up-to-date forecasts and advisories, visit https://www.weather.gov/mso/.

Reporter Mary Cloud Taylor can be reached at 758-4459 or mtaylor@dailyinterlake.com.