As Cold Air Approaches, Timing For Lowland Snow Is Uncertain

SEATTLE, WA — Heavier rains are on the way out after storms brought floodwaters to several rivers Tuesday. Now, forecasters are looking ahead to new weather systems that pack the potential for some lowland snow from Thursday into next week.

LATEST: Snow Arrives For Some In Washington, With More Chances On The Way

A CHANCE OF LOWLAND SNOW

According to the National Weather Service, the first chance for light, wet snow could arrive Wednesday night or Thursday morning, with the highest likelihood in western Whatcom and Skagit counties. NWS Seattle said a rain/snow mix is also possible in parts of Snohomish, King and Pierce counties. Another opportunity comes early Friday morning, where some snowfall may be possible north of Everett and along the foothills of the Cascades.

Forecasters said little to no accumulation is expected either day, and there is still a fair degree of uncertainty on timing and location. Snow levels Wednesday and Thursday are expected to hover between 1,000 and 2,000 feet, dropping down to the 500 to 1000 feet range by Friday morning.

In Seattle, Mayor Jenny Durkan scheduled a press conference with city transportation and emergency management officials Thursday morning to discuss winter weather preparations in the event of a snowstorm.

Wet weather may continue through the weekend, and temperatures are expected to drop below normal levels. NWS Seattle said the long-term forecast shows a high probability of a cold weather pattern settling into the region early next week, with daytime temperatures in the 30s, continuing the possibility for lowland snow. According to NWS meteorologists, there is a lot of uncertainty regarding snowfall this far in advance, since temperatures will likey be close to the margin, and the timing of moisture arriving is unknown.

MOUNTAIN PASSES

Drivers should plan for hazardous driving conditions in mountain passes, and an increased avalanche risk, through Wednesday afternoon. Forecasters expect 8 to 12 inches of new snow will fall at Stevens Pass, Snoqualmie Pass, White Pass and Mount Baker between Tuesday afternoon and 4 p.m. Wednesday.

Heavy mountain snow is expected to return to the Cascades Friday, impacting travel into the weekend. Stevens, Snoqualmie and White passes may pick up another 14 to 20 inches of new snow between Friday and Saturday.

RAIN UPDATE & FLOODING CONCERNS

Heavier rains are forecast to transition to showers early Wednesday, and most rivers should crest. A Flood Warning was still in effect for sections of multiple rivers Tuesday night, including the Snohomish, Snoqualmie, Skookumchuk and Stillaguamish. Flood Warnings for the Tolt, Samish, Skykomish, and North Fork Stillaguamish have ended.

The King County Flood Warning Center issued a Phase 2 flood alert for the White River Tuesday afternoon, with minor flooding possible near Auburn and Pacific. Increased landslide threats will continue due to the saturated ground.

Flooding Tuesday prompted the closure of several roads in King and Snohomish counties.