Mountain Weather Forecast

Weather Synopsis

A cool wintry pattern continues across the Pacific Northwest with highs in the upper 20s and low 30s and lows dropping into the upper 10s and 20s.

A surface and upper low has transited the Cascades and spins along the NE Oregon, SW Washington border. Wrap-around along the eastern edge of the Cascades should continue to diminish, but NNE flow may converge with NNW flow to the west of the Casades to produce some more sustained light to occasionally moderate snow over the central Washington Cascades. The location of this boundary likely extends from the mountain loop to the northern part of the Cascades East South zone.

Snow showers should focus increasingly on the west slopes of the Cascades as winds shift more westerly ahead of a weak upper low dropping down the Canadian coastline within the broader trough over the region. The cold air aloft should touch off instability showers with locally intense snow/graupel accumulations. At this time it appears that shower activity may focus more on the northern Washington Cascades in the morning and shift toward the southern Cascades as the low approaches the coastline and winds shift more easterly aloft over northern Washington but remain westerly further south.

The upper low continues to spin off the Washington coastline and shower activity gradually diminishes, but snow accumulations are more likley across the southern Washington Cascades and Mt. Hood areas. Easterly flow may produce some strong winds late Tuesday night and early Wednesday in places like Enumclaw, North bend, and Gold Bar.

On Wednesday, a surface low tracking toward the California/Oregon border moves south of our region, while cold air aloft with the slightly weakened upper level low should bring our region lighter winds and and afternoon instability snow/graupel showers.