Mountain Weather Forecast

Weather Synopsis

The first wave of moisture in a multi-day atmospheric river event is bottled up near and south of the Columbia River Gorge this afternoon. That will begin to change tonight as an upper level ridge of high pressure over the inland NW begins to flatten allowing moisture begins to stream inland/northward. We'll see a period of moderate precipitation with rising snow levels tonight with the heaviest totals once again most likely for the Mt Hood region and perhaps the Mt St Helens area.  Snow levels will rise to 6500-7500' tonight except along the east slopes of the Cascades near and north of Hwy2. As warm air pushes in aloft, there may be a transitory period of freezing rain this evening for Snoqualmie and White Passes, after midnight for Stevens Pass, late tonight and early Saturday morning along the Hwy2 corridor east of Stevens Pass including Tumwater Canyon. Even though we'll likely see some freezing rain tonight, this does not look like a significant icing event. 

The first wave of moisture should ease off Saturday morning with another one on its heels for Saturday. Precipitation should be relatively lighter during the day on Saturday. A stronger and wetter pulse of moisture will arrive Saturday night, likely delivering the heaviest precipitation period of the weekend. The eastern mountains north of Lake Chelan will likely see their snow levels rise into the mid-upper elevation range towards the end of the moderate precipitation early Sunday morning.  

The upper level ridge re-establishes itself over the inland NW on Sunday, shunting the heavier precipitation north and into British Columbia. Light rain will likely linger over the Olympics and northwest Cascades into the afternoon, with drier conditions found further east and south.