Significant Spring Storm: Strong Winds, Major Mountain Snow, and Heavy Rain

No FastCast today…read the full blog below for information about the strong spring storm that will impact the Pacific Northwest from Sunday to late Monday.

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A significant spring storm will impact the Pacific Northwest from Sunday to late Monday, with strong winds, major mountain snow, and heavy rain. 

The biggest impact of this storm will likely be the strong winds. Below is the European model showing peak winds on Monday afternoon.

This will be a region-wide windstorm…with gusts of 40-50 mph expected around the lowlands, with gusts up to 50-60 mph on the coast. 

For the lowlands, expect wind to come in 2 periods. Winds will increase starting midmorning on Sunday, becoming stronger from late Sunday night to early Monday morning. There will be a slight lull on Monday morning, before winds peak from late Monday morning through the evening. Isolated power outages and tree damage are both expected to occur with this storm.

Lesser winds are possible around Everett, due to a “meso-low” that will form on the leeward (east) side of the Olympics, decreasing winds there.

Winds will be strongest in Eastern Washington, as seen in the NWS Spokane graphic below.

Expect gusts in Eastern Washington to reach 45-65 mph, strongest on Monday afternoon and evening. Gusts of 70+ mph are possible in higher terrain. Power outages, tree damage, and blowing dust is expected in parts of Eastern Washington.

What is causing these strong winds? A strong low pressure center will move into British Columbia (just north of Vancouver Island), producing a large pressure gradient to its south (see UW forecast below for 8 AM Monday).

The gradient over Western Washington is in the red box…and you can see a strong pressure gradient (which produces winds) when the black lines on the model are closer together.

Another impact of this storm will be major mountain snow totals. Below is the NAM high resolution forecast, showing snow accumulations through 11 PM Monday.

Snow levels will drop below the passes on Sunday night. Expect snow totals of 12-30 inches at the passes by late Monday (most at Stevens Pass). Heavy snowfall rates of 1-2 inches per hour are possible from Sunday night through late Monday. Higher elevations may receive 3-4 feet. Additionally, there is a possibility for blowing snow and low visibility due to gusty winds in the passes on Monday.

Finally, this storm’s associated fronts will bring rain, heavy at times, to Western Washington. The European model forecast for rain through Monday evening is below.

Expect heavy rain totaling 0.9 to 1.5 inches in the lowlands, and 2-3 inches on the coast. Most rain will fall from Sunday evening to early Monday morning. River flooding is not expected, although some rivers will rise. Urban flooding (ponding & standing water) is possible as well.

Stay tuned for a storm update on Sunday evening as the storm begins! Updates are always available on @The_Weatherman2 Twitter (click Twitter logo on right side of the blog).