Rain, Wind, and Mountain Snow Expected on Saturday

FastCast—Saturday, Dec. 18 to Sunday, Dec. 19:

Another active Saturday is ahead, with rain, gusty winds, and mountain snow. Rain will be steady from late Friday through midday Saturday, totaling 0.75-1.25 inches. Winds will pick up overnight, peaking mid to late morning, then slowly diminishing through the afternoon as the front passes. Expect gusts up to 50 mph on the coast and in the North Sound, and up to 60 mph around Admiralty Inlet. Gusts of 35-45 mph are expected in the Lowlands, strongest near the water. Another round of mountain snow is expected as well. Expect 12-18 inches at the Passes, except 18-24 inches at Stevens Pass. Over two feet will fall at higher elevations (above 6,000 feet). Expect another difficult travel weekend on the passes, especially with added traffic for ski season and the holidays. Most snow will fall Saturday afternoon onward, and at Snoqualmie Pass, brief freezing rain, then all rain is expected until Saturday afternoon. Temperatures in the lowlands will rise to the upper 40s to low 50s in the lowlands on Saturday, cooling to the low 40s by Sunday. Lows will be in the mid 30s. 

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For the second weekend in a row, an active Saturday is expected. Rain, winds, and mountain snow are in the cards.

Below is the HRRR forecast for rain through 12 AM Sunday.

Expect around 0.75-1 inch of rain around the lowlands, with more on the coast/North Sound (1-3 inches) and less in the Olympic rain shadow.

Winds will increase as the cold front approaches. Expect winds to peak in the early morning in the North Sound and mid to late morning in the lowlands. Gusts will reach 45-50 mph on the coast/North Sound, 50-60 mph around Admiralty Inlet, and 35-45 mph in the lowlands (highest near water).

Below is the HRRR forecast for peak winds in the Interior Lowlands (around 11 AM a Saturday).

The strongest gusts in the lowlands (35-45 mph) are expected near the water. Isolated power outages and some tree damage may occur around Western Washington. 

For the second weekend in a row, some significant mountain snow is expected. Below is a helpful NWS Seattle graphic showing expected snow through 10 AM Sunday.

At the passes, expect the heaviest snow from Saturday afternoon onward (after frontal passage), though it will likely snow at the passes before then, except Snoqualmie Pass. At Snoqualmie, it will rain (with potential freezing rain in the morning) until the afternoon/evening, when the snow level will drop below 3,000 feet.

A colder day (low 40s) with rain beginning for the next system by late evening. The next system will move in on Sunday night/Monday, with more rain and mountain snow.