Mountain Weather Forecast

Weather Synopsis for Saturday & Thursday

A powerful frontal system brings the final act of a potent atmospheric river event. As the front approaches, locations in the water hose have been receiving significantly more water than the forecast models predicted. The front should move SE today and has been slightly slower than anticipated, but it should continue to progress through the region, bringing heavy rain and snow with gradually lowering snow levels (in the 5000-6000 ft range) as it approaches with rapidly lowering snow levels behind it, bringing snow down to near sea level in many locations by this evening. 1-2" of snow water equivalent are expected from 4 AM to 4 PM on Saturday for Mt. Baker, Snoqualmie, Stevens, and White Passes, and also Mt. Hood. Most areas should see significantly more rain than snow, but Mt. Hood may be closer to a 50/50 split. Post-frontal snow shower activity should feature moderate convergence, which is likely to focus toward Snoqualmie Pass and may increase snowfall amounts there vs. the 1-3" amounts we expect at 3000-4000 ft on the west slopes of the Cascades. Expect higher snowfall amounts at higher elevations where snow starts earlier.

Strong to extreme SW winds should switch westerly with the frontal passage and decrease, although they will sustain longer through the mountain gaps and on higher ridges E of the Cascade Crest, and particularly Mt. Hood.

Light snow shower activity should continue across the west slopes of the Cascades with snow levels between 0-1000 ft tonight and after a bit of a break Sunday morning some light snowfall should pick up late morning on Sunday on the coast (the Olympics) with a weak shortwave trough. Snow levels will stay very low.