New Year’s snowstorm to usher in coldest air since 2014 across parts of northwestern US

By Jordan Root, AccuWeather meteorologist

December 31,2016, 11:34:54PM,EST

 

 Arctic air will plunge into the Northwest over the next few days and bring a frigid and snowy start to 2017.

A snowstorm will precede and accompany the arctic surge and create slippery travel over much of the region from New Year's Day to Monday. A mix of rain and snow is forecast along the immediate coast at sea level.
Some rain and snow will fall around Seattle and Portland, Oregon, through New Year’s Day. Hilly areas around Seattle and outlying higher elevations around Portland can pick up a couple inches of snow. Most of the snow accumulation will be on non-paved surfaces. However, some bridges and overpasses could get slippery, especially as temperatures plummet toward the end of the storm.

"This will be the first storm with wintry precipitation in the Seattle and Portland areas spanning New Year's Eve and New Year's Day since Dec. 31, 2003 and Jan. 1, 2004," according to AccuWeather Senior Meteorologist Alex Sosnowski. "That storm brought about 4 inches of snow to that part of the Interstate 5 corridor."
While there can be light accumulations around Seattle and Portland, the best chance for heavy snow will be focused across the Cascades where 6 to 12 inches will fall. Heavy snow will also fall across the Bitterroots.
Travel along I-84 through the Columbia River Gorge and I-90 through the Cascades on east can be treacherous for a time on Sunday.

While only a small amount of snow will fall at low elevations in this area, untreated wet highways, streets and sidewalks can turn icy as temperatures plunge with the push of arctic air. Major cities over the interior Northwest to be affected by the snow and freeze-up include Spokane, Washington, Pendleton, Oregon, and Boise, Idaho.
The swath of rain and snow will spread farther south and east Sunday night and Monday. Salt Lake City will endure snowy conditions during this time with travel being impacted. Snow will spread into the northern Sierra as well where a foot of snow may pile up.
Arctic air will pour into much of the West during the first week of the new year.
Daytime temperatures will generally range between 10 and 20 degrees Fahrenheit below normal for a few days, although in some areas, temperatures may fall up to 30 degrees below normal.
Some cities may come close to tying or even breaking low temperature records. The coldest air will be in place between Monday and Wednesday.

Cities such as Seattle and Spokane, Washington; Portland, Oregon; Boise, Idaho; Missoula and Great Falls, Montana; will all face the cold next week.
An easterly wind through the Columbia Gorge will funnel the arctic air into Portland Monday through Wednesday.
“Portland will endure several days with high temperatures in the 20s to near 30 next week,” AccuWeather Senior Meteorologist Dan Pydynowski said.
Overnight lows in Portland will rival records this week as temperatures dip into the teens through Wednesday night. This will be some of the coldest air felt since February of 2014.
Boise, Idaho, may also approach records on a couple of nights next week as temperatures sink well below zero.
Those heading outside may want to consider putting on extra layers.
RELATED LINKS:
Western US blog
Northwestern US radar
128th Rose Parade: Dry, cool weather to kick off event in Pasadena
An Arctic high pressure system remain in control across the Northwest through most of the week and will keep the region dry. However, the cold air will keep a firm grip on the region.
“The Northwest looks to remain colder than normal right into the first weekend of the new year,” Pydynowski said.
The cold air may even make it as far south as Las Vegas by the end of the week, bringing temperatures 10 to 15 degrees below normal.