Mountain Weather Forecast

Weather Synopsis

Light snow showers continue to rotate around a relatively stationary low parked off Haida Gwaii, with light SSW flow focusing most of the shower activity on the southern slopes of the Olympics. Low-level flow has switched easterly and should gradually increase through Sunday. An expanding subtle ridge helps cut off residual snow shower activity across the mountains of northern Washington Saturday evening, allowing skies to mostly clear overnight. Expect temperatures to drop into the lower 20s in many areas.

A perturbation moving toward the region on a SW flow taps into significant moisture as it develops Saturday night, lifting a warm front with increasing light snow to the area on Sunday. Snow starts around Mt. Hood in the morning hours, spreading into the southern Washington Cascades by mid-morning and the rest of the region during the late morning and afternoon hours. Snow may become moderate by the afternoon for Hood and the southern Washington volcanoes. SSW will bring in the moisture while low-level E winds bring allow for significant spillover onto the east slopes.

Moderate to heavy snow intensifies across the region Sunday night as the cold frontal boundary lingers over western Washington. The cold front shifts slowly from NW to SE across the area on Monday, allowing precipitation to ease into the moderate range in some areas. However, convergence focused on the Mt. Baker area could keep snowfall significantly higher in this vicinity. It remains uncertain when snow levels will peak, but Monday morning will be the most likely with snow levels rising to around 3500 ft. Conditions will be messy at Snoqualmie Pass with E winds shifting W as flow aloft shifts from SW to W with the front.

Snow totals above 4000 ft should be in the 1-2.5 ft range through Monday with the heaviest precipitation over the volcanoes and near the Cascade Crest.