After an unseasonably quiet start to December in the northwestern United States, a significant storm will set its sights on the region spanning Tuesday to Wednesday.
People with plans to travel over mountain passes in the Cascades next week should anticipate major delays, chain requirements and possible closures. Flights into and out of Seattle and Portland, Oregon, may be delayed by wet weather and low clouds.
The Northwest’s break from storminess is coming to an end, AccuWeather Senior Meteorologist Jack Boston said.
The pattern of frequent storms rolling ashore during November ceased after the first few days of December.
After rainfall exceeded average levels last month, Seattle and Portland received well below-normal precipitation during the first half of December.
“The renewed Pacific jet will bring storminess into the (Pacific Northwest), with some rain and mountain snow next week,” Boston said.
A wave of rain and high-country snow across Washington and the northern Rockies from Sunday to Monday will be followed by a more potent surge of moisture and cold air Tuesday into Wednesday.
Because little rain has fallen since the beginning of the month, oil has had a chance to build up on the roadways. This will create a slick layer on the road surface at the onset of rain, including on Interstate 5 from Seattle to Portland and Eugene, Oregon.
Motorists should slow down to avoid hydroplaning at highway speeds.
In the Cascade Range of Washington and Oregon, the passes are expected to quickly become snow covered and slippery by Tuesday night as cold air drops south.
Snow levels will lower from above 5,000 feet to 2,000-3,000 feet during the storm. Snowflakes could even make it down to the foothills of the Cascades and coastal ranges during the latter half of the storm.
Several inches of snow are expected to accumulate over Interstate 90’s Snoqualmie Pass and U.S. Highway 2 through Stevens Pass in Washington.
Lolo and Emigrant passes in Oregon will also be whitened by a slick covering of snow.
The snow will come to the delight of skiers as the highest elevations could be buried under a foot of fresh powder.
As the storm quickly progresses southeastward across the West at midweek, snow and localized blizzard conditions may unfold across the Rockies and northern Plains.
Source: News agencies