Mother Nature is shaking up a wintry cocktail of mountain snow, lowland rain and breezy winds to pour over the region well into next week.
An initial front brushing the coast will bring showers to Western Washington on Friday morning, but it won’t be “terribly impressive,” the National Weather Service said.
The bigger weather maker — a trailing blob of cold air moving southeast out of the Gulf of Alaska — will deliver steady rain by Friday evening as it drags across the Interstate 5 corridor, transitioning into mountain snow.
Most lowland areas will receive half an inch of rain with Friday’s system, said Harrison Rademacher, a meteorologist with the weather service in Seattle.
Cross-state travel will be impacted as snow elevations fall to around 1,500 feet by Saturday afternoon. The system is expected to produce 9 to 15 inches of snowfall across the Cascade passes, with up to 2 feet in higher elevations. Because of that, the weather service issued a winter weather advisory in effect from 4 p.m. Friday through 4 a.m. Sunday.
Winds over the northwest interior and along the north coast will be breezy with the arrival of the incoming system, with gusts up to 40 mph Friday afternoon through the night, the weather service said.
Saturday will see lowland rain and mountain snow locked in place for much of the day.
Temperatures across the region through the first half of the weekend will hug seasonal averages, with highs generally in the mid to upper 40s. Overnight lows will similarly see little in the way of variation, generally hovering in the upper 30s to lower 40s.
Sunday will be the driest day in the near future, but it’s not expected to be warm. Seattle’s forecast high of 42 degrees would be the coolest day since Nov. 29’s high of 39 degrees, the weather service said.
Snow elevations are expected to hover near 1,000 feet Sunday night, which could deliver wet flakes across Whatcom County and the Kitsap Peninsula by Monday morning.
Lowland rain and mountain snow are expected to quickly resume at the start of the workweek, while snow elevations stop short of 3,500 feet, welcoming another round of snow in the passes.
With the series of systems rolling through the region, Seattle’s yearly rainfall total is expected to be above normal for the first time since 2022, according to the weather service.
Another system will roll through the region Tuesday, shaking out 1 to 2 feet of snow in the mountains.
“Temperatures will start to drop off a little bit going into Tuesday and Wednesday,” Rademacher said, “so there’s a likely scenario where we see temperatures in the Seattle area potentially below freezing.”
With a pool of Canadian cool air situated above us on Wednesday, snow elevations could drop down to as low as 500 feet in the north and 1,000 feet in the south — but moisture amounts are decreasing, so precipitation will be limited.
As for lowland snow next week?
“It’s still something we’re keeping an eye on,” Rademacher said.
