Mountain Weather Forecast

Weather Synopsis

It's a stormy afternoon across most of our moutains, especially near and south of I-90. The main band of precipitation will continue to lift northward and finally bring precipitation to the Mt Baker and Washington Pass areas late in the day and into the evening. An approaching trough will shove the weakening out of the region overnight. Behind the main system onshore flow (west), plenty of low level moisture, and a relatively unstable atmosphere will focus showers along the west slopes of the Olympics and Cascades with markedly less snow making it further east. A Puget Sound Convergence Zone forms in the evening and focuses heavier precipitation near the southern Mt Loop Hwy and Stevens Pass areas. These narrow bands of intense rain/snow are hard to nail down. It looks like most of the precipitation stays north of Snoqualmie Pass, but if it shifts south, expect higher now totals in both passes. Moderate to strong and gusty westerly winds should build and peak into the evening before slowly decreasing overnight. 

Post-frontal showers continue Monday primarily for the west slopes, passes, and Mt Hood areas. As the weakening low-pressure center shifts inland, it could reinvigorate shower activity in the afternoon. While low to mid-level clouds will linger in most locations, you could see a few sun breaks further east and along the Cascade Crest near Crystal and Mt Adams. 

A transient high pressure ridge approaches the region Monday evening and finally puts and end to any final showers. This starts a relatively short break in the action stretching from Monday night through Tuesday evening. Expect drying and some clearing. This could result in low clouds and valley fog overnight. On Tuesday, most locations should find appreciable sunshine before high clouds enter the Pacific Northwest ahead of our next storm.