Powerful Storm to Slam Pacific Northwest With Rain, Wind

By Brian Thompson, Meteorologist

September 25,2013; 9:06PM,EDT

 

 

 

After a fairly quiet few days ahead, several rounds of heavy rain, high winds, rough seas and even mountain snow will impact the Pacific Northwest over the weekend and into early next week.
Travel will likely be slowed by the heavy rain, localized flooding and gusty winds from Vancouver down through Seattle and Portland. Strong winds will raise seas and could also cause disruptions and damage.
All indications are that a powerful, early season storm system will dive into the Gulf of Alaska on Friday. The storm will not move much over the weekend before it finally weakens and moves eastward by late on Monday.

Disturbances moving around the storm will bring rounds of locally heavy rain to southwestern British Columbia, western Washington and northwestern Washington.
As the storm first establishes itself on Friday, some rain will move into western Washington and British Columbia. A powerful disturbance moving around the storm will bring the threat for locally heavy rain on Saturday.
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The next round of heavy rain could be enhanced by the moisture leftover from what is now Typhoon Pabuk, which was centered near Japan on Wednesday. This would bring more heavy rain later on Sunday into Monday.
Typhoon Pabuk will pass to the east of Japan through Thursday before weakening and racing eastward across the North Pacific over the next few days. Some leftover moisture from the storm may impact the Pacific Northwest late on Sunday and Monday.
From Friday through Monday, rainfall amounts of over 6 inches (15 cm) will be possible over the high terrain of the Olympic Peninsula, southwestern British Columbia including Vancouver Island, and the Cascades of Washington.
While lesser amounts are expected from Vancouver to Seattle and Portland, 1 to 3 inches (3 to 8 cm) of rain appears likely in these areas.
The Seattle Mariners have games scheduled at Safeco Field both on Saturday and Sunday. Given how persistent the rain may be, outdoor activities will be difficult to squeeze in at times over the weekend.
While some snow will fall at pass level over the Cascades into Thursday associated with a storm over the Rockies, snow levels will initially be high over the weekend. Only the high country above 9,000 feet is likely to receive accumulating snow.
Snow levels will lower to around 6,000 feet by Monday. Significant snow is generally expected to remain above pass level for most locations into early next week, so major travel problems are not anticipated due to the snow.
The strong onshore flow around this storm will also lead to rough seas. Wave heights off the Washington coast and along the western coast of Vancouver Island, B.C., could build to between 15 and 30 feet.
Winds will be strongest along the immediate coast and the west-facing slopes of the Olympic and Cascade ranges, where gusts of 50 mph or more could cause downed trees, power outages and minor property damage over the weekend.
As the storm finally weakens and drifts away on Monday, conditions should begin to improve by Tuesday with just some leftover showers.

Expert Senior Meteorologist Alex Sosnowski contributed content to this story.