Rain, Wind, and Mountain Snow on Tuesday, Drier Midweek

 FastCast—Tuesday, Feb. 7 to Friday, Feb. 10:

A frontal system will bring rain, wind, and significant mountain snow to Western Washington on Tuesday. Across the lowlands, expect 0.2-0.5 inches of rain, with higher amounts possible under Convergence Zone bands north of Seattle. On the coast, expect 1-3 inches of rain. The mountains will receive significant snow. Expect 8-16 inches at Snoqualmie Pass and 18-30 inches at Stevens Pass, mainly on Tuesday. Travel delays are possible, so go prepared. This will also be a breezy system, with 30-40 mph gusts possible across the region, with higher gusts possible along the water, on the coast, and in the North Sound. Conditions dry out and will be partly cloudy on Wednesday and Thursday, before showers return late Thursday night through Friday. Generally, expect lowland highs in the upper 40s to low 50s (except mid 50s on Thursday), with lows in the upper 30s to low 40s.

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Continue reading the full blog below!

An active system is approaching Western Washington, moving through on Tuesday. Expect rain, wind, and significant mountain snow…which is where we’ll start. 

Below is the European model for snow through 10 PM Wednesday. 

Expect 8-16 inches of snow at Snoqualmie Pass and 18-30 inches at Stevens Pass. The European model also shows the slight possibility of brief foothill snow early Wednesday, mainly from I-90 northward.

The NAM high resolution model is below, also showing snow through 10 PM Wednesday.

The NAM backs up the European model, showing 8-12 inches at Snoqualmie Pass and 18-30 inches at Stevens Pass. 

This system will bring rain and wind to the lowlands on Tuesday. Below is the European model’s forecast for wind on Tuesday afternoon.

The European model shows winds gusting 30-40 mph across the lowlands, with some gusts up to 45 mph in the North Sound. 

The NAM model shows winds peaking earlier (7-10 AM) and stronger, as seen below.

The NAM shows area-wide winds gusting 40-45 mph, with some gusts to 50 mph along the coast and close to Puget Sound. This solution is less likely but remains possible.

Finally, this system will also bring rain to the lowlands. Below is the European model showing total rain through 10 PM Wednesday.

The European model shows 2 rain shadows…one in the typical location NE of the Olympic Peninsula, and another from Seattle to Tacoma. In these areas, expect 0.2-0.4 inches of rain. Outside these rain shadows, expect 0.5-1 inch of rain, except 1-3 inches on the coast. These rain shadows are due to the angle of the approaching system, which can determine what areas receive the most rain.

Let’s see if the NAM model verifies this forecast, showing total rain through 10 PM Wednesday below.

The NAM shows less precipitation entirely for the lowlands, with 0.1-0.4 inches for all the lowlands, except 0.5-1 inch on the Kitsap Peninsula and around Everett due to a potential Convergence Zone. Areas from Olympia westward to the coast get 0.8-1.5 inches, with 2-3 inches on the North Coast. 

While there is some disagreement regarding precipitation placement and amounts, no impacts are expected from the rain, and the additional mountain snow will help to boost our snowpack closer to average.