Weather Synopsis for Saturday night through Monday

A classic spring cold front should reach the Washington coastline around 3 PM on Saturday. SE winds ahead of the front, combined with sunny skies, will bring temperatures into the upper 60s and low 70s across the Puget Sound lowlands, with 40s and low 50s widespread in the mountains. The arrival of the cold front will sharply correct these above-normal temperatures across the region as it progresses through our region Monday evening and overnight. Expect a 3-hour band of light to moderate precipitation for the west slopes of the Cascades, with more sustained moderate precipitation for much of the night from Highway 20 northward as a convergence band likely forms in the early morning hours. Snowfall amounts should be less than 3" in most areas, with 3-7" north of Highway 20. Snow levels start around 4500-5000 ft, but drop below 3000 ft overnight. Moderate S winds will accompany the front, switching SW overnight and W on Sunday before gradually decreasing.

The Pacific Northwest sits under a trailing trough featuring scattered to isolated light snow showers with locally more intense precipitation rates in increasingly convective showers driven by cold air aloft. These convective showers will allow for some spillover onto the E slopes of the Cascades, but snowfall amounts during the day should be a few inches or less in favored areas. Snow levels should stay below around 3000 ft, but accumulations are unlikely below 3500 ft during the daytime.

Lingering showers quickly dissipate Sunday evening with clearing skies overnight as an offshore ridge expands into the region. Monday should feature a cool start, with warming throughout the day.