Wet weekend: Storm to hammer Northwest with rounds of rain, gusty winds and even some snow

A storm advancing eastward across the open waters of the Pacific Ocean this week will move into the northwestern United States and British Columbia, Canada, into the start of this weekend, AccuWeather forecasters say.

This storm is expected to bring rounds of rain and showers, gusty winds at the coast and disruptions to travelers to western Washington and western Oregon beginning Friday night.

Winds along the shorelines and even over the open ocean are projected to peak on Friday as the initial front arrives. Gusts at the beaches can range up to 35-45 mph for a time while offshore winds can gust higher to 50-60 mph. Less-experienced mariners and those operating smaller vessels in the area are recommended to stay in port and avoid the hazardous conditions this storm will bring on Friday.

As waves of moisture shift into the Pacific Northwest over the weekend, rainfall totals can range from 1-3 inches across portions of western Washington and Oregon. Locally higher rainfall amounts can occur across the upslope regions of the Coastal Range and Cascade Mountains.

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The heaviest rain is likely to occur on Sunday across coastal Oregon when rainfall rates could exceed 0.50-0.75 of an inch per hour. The wet weekend ahead can lead to localized flooding in low-lying and poor drainage areas, particularly in upslope regions that collect between 2 and 3 inches of rainfall.

So far, locations in northwestern Washington, such as Olympia and Seattle, have collected only around 35% of their typical monthly rainfall for October, so this storm may help boost moisture before the month ends.

Through Sunday, most of the snowflakes will be isolated to the higher terrain across British Columbia and the far northern Washington Cascades.

As cooler air spills southward from Canada Sunday into Monday, snow levels will lower across Washington, Oregon and the surrounding states, which could lead to slick spots on roadways, especially secondary roads that are less heavily traveled.

"Colder air will filter into the Pacific Northwest Sunday night into Monday, bringing snow levels to some of their lowest snow levels of the season so far in the Washington Cascades. Snow levels may lower to 3,500 feet during this time, bringing some snow to some of the higher passes, such as Stevens Pass in Washington state," explained AccuWeather Senior Meteorologist Dan Pydynowski.

"Along Interstate 90, it will likely just be a chilly rain around Snoqualmie Pass Sunday night into Monday. By Monday night into Tuesday, snow levels could even lower more to around 3,000 feet, perhaps bringing some wet snow or a mix of rain and wet snow to even lower passes such as Snoqualmie by then," added Pydynowski.

The cooler conditions will continue to expand across the Northwest and interior West early next week. For some locations across the lower elevations, it may be noticeably cooler by a few degrees but not quite chilly enough to allow for a mix of wet snowflakes.

Even without snow, travel could still be slower on I-90 Sunday into Monday and Tuesday with wet roads and reduced visibility during rain showers.

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