The most powerful storm since last winter is expected to pound the Northwest later this week with fierce winds, heavy rain and disruptive snow. Forecasters are saying that it could end up being one of the most intense storms of the entire wet season, which typically begins in the fall and lasts through the winter months.
Initially, rain began to fall along the coast in cities such as Seattle and Portland during the midday hours on Thursday. As precipitation moves farther inland on Thursday night, some snow may fall in the Cascades. Neither rain nor snow amounts are forecast to be particularly high with this first round of precipitation.
Snow levels will dip to around 2,000 feet, which is low enough to make for a fresh dose of slippery conditions over the passes in the Cascades during the first round into Thursday night. On Wednesday, snow remained on the high spots of the passes due to a storm that brought snow earlier this week and forced the closure of some passes. Motorists should be prepared for a new round of winter driving conditions over Snoqualmie Pass along Interstate 90 and Stevens Pass along U.S. Route 2, both in Washington, as a result.
Rain will begin to increase in intensity late Thursday night and Friday morning as the main part of the storm approaches.
Sheets of rain will pelt the coasts of Washington, Oregon and Northern California as the storm slams into the region on Friday. Given the strength of the storm, winds will rapidly increase to disruptive and damaging levels as well.
The storm will move farther inland on Friday night, and the heavy precipitation will follow suit. Any mix of rain or snow in the passes of the Washington Cascades will change over to all snow as colder air moves in and causes freezing levels to dip.
Future radar shows rain, a wintry mix and snow spreading across the Nothwest on Friday afternoon local time.
"This will be the first significant snowstorm of the season for the Washington Cascades," said AccuWeather Senior Meteorologist Mike Doll. "Snow levels will fall to pass level and travel on U.S. Route 2 and I-90 could become dangerous due to the combination of heavy snow and blowing snow."
A general 1-2 feet of snow is forecast to fall above 4,000 feet in elevation with an AccuWeather Local StormMax™ of 40 inches anticipated over the ridges and peaks in the Cascades and northern Rockies. More than a foot of snow is expected at pass level in the Washington Cascades.
High winds will be widespread across the region, adding to the dangers of the storm. Wind-driven rain and blowing and drifting snow will drastically reduce visibility. Not only will it be difficult to see if traveling, but the winds are likely to cause other problems as well.
"Gusts frequenting 50-60 mph are likely along the immediate coasts of Oregon and southern Washington with locally stronger bursts of wind that could approach hurricane-force (74 mph or greater) from Friday afternoon to Friday night," according to AccuWeather Senior Meteorologist Alex Sosnowski.
"The concern is winds will be strong enough to down trees and power lines. Power outages are a risk for the Seattle and Portland metro areas," Doll said.
Loose items such as trash cans and patio furniture could become projectiles in the strong winds.
"It will be a beast of a storm," AccuWeather Senior Meteorologist Alex Sosnowski said, adding that it could end up being one of the most intense of the entire season.
As the storm moves inland, it will slowly lose intensity. But, several inches of snow could fall in the mountains of Idaho, western Montana, western Wyoming and the mountains east of Salt Lake City.
In locations where heavy snow falls and/or strong winds cause power outages, it could take several days for electricity to be restored. People with generators may want to make sure their equipment is in operating order in advance of the storm.
More rain and snow may be in the offing to end the weekend and begin next week.
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