Mountain Weather Forecast

Weather Synopsis

The stars have aligned this week for cold temperatures and moisture as a productive snow-producing pattern continues across the Pacific Northwest. Let's dive into the details...

A strong cold front is draped across NW Washington on Tuesday afternoon. A wide swath of heavy precipitation extends out ahead of that front, with moderate to heavy snowfall occurring across the Cascades. Temperatures have remained below freezing at Snoqualmie Pass, but expect them to climb a degree or two and peak with the frontal passage during the evening hours (4 PM for Mt Baker, 7 PM for Snoqualmie Pass, 10 PM for Mt Hood). This timing means that heavy snow and the strongest winds will continue through the evening hours in the southern Cascades. This frontal passage marks the transition from heavy snowfall to post-frontal snow showers, which will be locally intense and are unlikely to feel showery on the west slopes of the Cascades, thanks to sustained moderate WSW winds and mountain enhancement. Attention shifts to the Highway 2 corridor overnight, where most models focus on a narrow but strong zone of convergence from 10 PM to 4 AM in the vicinity of Stevens Pass. This could deliver 8-12" of lower-density snowfall as temperatures drop, and mix moderate winds down toward the Pass level. 

By Wednesday, the convergence ends, leaving ongoing light to moderate snow showers. By late morning, winds shift more SSWerly ahead of a secondary frontal feature. Expect a period of moderate to heavy low-density snowfall as this front moves through the Cascades. Snow levels will fluctuate between 1000 and 2000 ft. Expecting a shifting focus of the light to moderate ridgeline winds as this feature transits the region.

Stevens Pass might be playing with house money Wednesday night as models indicate moderate confidence in another band setting up in the Highway 2 vicinity. Elsewhere, decreasing moderate post-frontal snow showers continue as moderate W winds increase through the evening hours. Snow levels drop to 500-1000 early Thursday, rising around 1000 ft by the afternoon as light to locally moderate low-density snowfall continues. Expect moderate to locally strong winds to continue near and east of the Cascade Crest through the day.