Mountain Weather Forecast

Weather Synopsis

A winter storm approaches the region Saturday night. Light rain and snow arrive in the Olympics and Mt. Baker during the evening before increasing in intensity in these areas and spreading to other parts of Washington State overnight. Snow levels should be around 3000-4000 ft range. Snoqualmie Pass may get some mixed precipitation as low-level E flow continues.

Rain and snow intensify across the northern Cascades and Olympics on Sunday as the occluded frontal system arrives on Sunday. Models are having difficulty deciding how much moisture will be in the warm sector of the storm from the central and southern Washington Cascades, but overall these areas may have much lighter precipitation with breaks possible during the mid-day hours. With the warm front likely to lift north to around the mountain loop area, expect snow levels to rise up to 4000-5000 ft across the central and southern Washington Cascades. Moderate WSW winds become strong and shift to the SSW in the Olympics, Mt. Baker, Mt. Hood, and Crystal mountain areas late in the day as the cold front approaches.

We may see a change back to mixed precipitation as the flow aloft takes a more southerly component and light E flow keeps cold air trapped near the surface trickling through Snoqualmie Pass. Expect a period of heavy rain and snow Sunday evening as the cold front arrives with strong winds. The Cascade Passes should shift back to all snow by the late evening hours as a moderate push of westerly winds brings moderate snow with heavy convergence bands with the upper trough moving in behind the front.

NW flow will bring a weak disturbance through on Monday, bringing light to moderate snow showers and convergence focused from Snoqualmie Pass to the Mountain loop. Colder than average temperatures will produce high snow to water ratios.