Snowy week in store for Northwest as Arctic air, Pacific storms collide

Alex Sosnowski

As some residents of the northwestern United States are digging out from heavy snow and facing travel delays due to wintry weather, forecasters say a parade of storms and plenty of Arctic air will keep the hits coming this week.

The biggest storm of the bunch is slated to hit later this week, and it could trigger major winter storm conditions in lower elevations, including in Seattle and Portland.

A rather far south storm track into the Pacific coast will not only allow Arctic air to keep plunging across the Pacific Northwest, but it will also dip far enough to the south to douse much of California with rain and mountain snow this week.

A pedestrian carrying an umbrella walks near Pike Place Market as snow falls Monday, Feb. 11, 2019, in downtown Seattle. Schools were closed across Washington state as winter snowstorms continued pummeling the Northwest. Seattle's metro area had already been hit by three snowstorms in February, making it the snowiest month in Seattle in more than 30 years. (AP Photo/Ted S. Warren)

None of the systems are expected to be blockbuster snow events like the double-barreled storm that immobilized travel in the Seattle area during February 2019 and unleashed 17.5 inches of snow at Seattle Tacoma International Airport. However, the Pacific storms are expected to bring rounds of wintry precipitation to many areas and may lead to their share of travel delays and hazards.

From Sunday to early Monday, a few inches of snow already fell on communities surrounding Lake Washington in western Washington. Between 6 and 10 inches of snow fell from Friday to Sunday in the Spokane, Washington, area.

The next storm in the series from the Pacific is forecast to move ashore later Wednesday, Wednesday night and Thursday.

Enough cold air is likely to linger to bring the potential for a few more inches of snow to low elevation and coastal areas of Washington and northwestern Oregon.

"With all of the cold already in place in the Northwest, the storm coming for the middle of the week will present the best chance for accumulating snow in cities like Portland and Seattle," AccuWeather Meteorologist Rob Richards said.

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The Cascades may break up some of the moisture from the midweek storm; however, a few inches of snow are likely to fall over the central and eastern portions of Washington and Oregon.

Snow will continue to pile up over the Olympics and Cascades during and in between the storms. With snow levels down to sea level much of the time this week, travel over the passes will be difficult and nearly impossible without properly equipped vehicles.

The heaviest snow is likely to take aim at the Oregon Cascades and the northern Sierra Nevada, where up to a few feet of snow may pile up over the high country with several inches of snow to a foot likely at Siskiyou Summit in Oregon and Donner Pass in California.

Rain is forecast to spread southward across the southern coast of Oregon and much of the balance of California during Wednesday night and Thursday, potentially bringing parts of Southern California the most significant rainfall since around Christmastime and snow and slippery travel along the Grapevine.

The weather pattern is forecast to begin to change around the end of the week and this weekend.

"A storm that spirals ashore spanning Friday and Saturday may mark the beginning of another pattern change," said AccuWeather Senior Meteorologist Brett Anderson.

By then, Arctic air will have become stale and sloshed eastward toward the Plains. This should allow somewhat milder ocean air to filter onshore and trigger rising snow levels over the West Coast states in general.

Even though milder air will end the snowy episodes at sea level along the Washington and northern Oregon coasts, snow is likely to continue to fall over the passes in the Northwest and across the interior of the region as the weekend storm strikes.

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