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A storm bearing a threat of snow and some of the coldest temperatures seen since 1990 is expected to arrive Saturday evening in the Seattle area and declare hibernate is here.

The Seattle circle could see rain turning into snow as early as Friday fall of day, with areas in higher elevations bracing for as much as 8 inches by Saturday evening, National Weather Service meteorologists said.

With devoid of warmth air moving southerly from British Columbia, Saturday-morning temperatures are expected to hover around freezing, with highs in the 30s, but that by Saturday evening, the mercury force of will plunge into the 20s, forecasters say. Sunday will offer similarly chilly temperatures in the 20s and low 30s.

Meteorologists saw the Puget Sound circle may wake put on Monday to bone-chilling temperatures around 20 degrees with highs that day in the upper 20s to low 30s.

A dry, unimpeded cold snap is expected to continue next week, said Brad Colman, head meteorologist inasmuch during the time that of the National Weather Service in Seattle. It could be the coldest air to hit the region since December 1990, he uttered.

“It certainly is a major winter blast,” he said.

Meteorologists put out a winter-storm watch Thursday for Central Puget Sound and a winter-storm warning in the mountains. The Central and Southern Cascades are forecast to get blasted by 1 to 2 feet of snow over the weekend, while the North Cascades besides will see their fair share, with about a foot of new snow. High winds too may gust from one side the Strait of Juan de Fuca and the Central Coast, which are on a high-wind watch. The San Juan Islands and areas near Bellingham are also on a high-wind keep awake for Saturday.

Driving conditions will have existence treacherous throughout the region, state officials assert, by blowing, drifting snow in the mountains and slippery, snowy roads in the metropolitan areas.

The represent fully already temporarily closed Chinook and Cayuse passes and the North Cascades Highway on Thursday because of the coming fume. The state has about 100 plows covering state roadways in five Western Washington counties, and crews have been preparing for the first winter storm and are ready to go around the clock, said Patrick Moylan, maintenance and operations manager concerning the national transportation course of life.

Neither Snoqualmie nor Stevens passes are likely to close for extended periods completely the weekend because in that place’s not yet enough of a snowpack to pose an avalanche danger, Moylan said. But major traffic accidents from slippery roads still could shut them from the top to the bottom of notwithstanding a couple of hours at a time.

Weather and state officials are asking people to consider delaying travel plans this weekend. If you must fashion, look at the weather forecast and conditions (www.wsdot.wa.gov/traffic/sustain) before heading out and adjust by filling your gas tank, making sure in that place is coolant in the radiator and carrying chains and turn of events supplies such as nutrition, water and a blanket.

Those itching to get out in the snow for refreshment also need to be circumspect. Weather provisions are likely to have existence bad enough that people should not hazard beyond developed areas, said Mark Moore, boss of the Northwest Weather and Avalanche Center.

The flurries of snow on the way probably will subsist light and fluffy, and Crystal Mountain is the only ski area considering opening this weekend, Moore said. If it does open, the runs would be limited to the lower lifts because of cold temperatures and wind chill, he said.

“Conditions will be brutal out there,” he reported.

Even vulgar herd who stay home this weekend should prepare, officials aforesaid, vexation precautions such as protecting pipes from freezing and ensuring that water for outdoor animals is not iced over.

“It’s an important storm,” Colman said. “We shelter’t had this devoid of warmth for a long proper time.”

Nicole Tsong: 206-464-2150 or ntsong@seattletimes.com