Mountain Weather Forecast

Weather Synopsis

An approaching frontal system has spread mid-level clouds through much of NW Washington on Saturday afternoon. These clouds should lower and thicken as the surface low slides down the British Columbia coastline and the front continues to pivot toward the PNW coast.

Snow spreads from NW to SE overnight, increasing in intensity. With dry air across the region, we're expecting a slight delay in the precipitation as the atmosphere saturates. Temperatures should quickly drop as the precipitation moves in. Snow levels start around 1000 ft in most areas. Increasing SSW winds don't have much warm air to tap into following the very deep trough that extended throughout the western US. SSW winds ramp up in advance of the front into the moderate to locally strong range. Mt. Baker will be favored for precipitation totals with heavy snowfall and winds potentially exceeding forecast numbers in the vicinity of the ski area. Light E winds should allow for some spillover onto the E slopes, but amounts should remain generally light.

Post-frontal westerlies increase behind the front on Sunday and peak during the mid-day hours. Moderate snow showers in the morning decrease during the afternoon. Models indicate the potential for convergence enhancement Sunday into Sunday evening, with potential formation around Stevens Pass or further north. By late in the day, snow levels should be between 0-500 ft. Expect 6-20" of snow by late Sunday for the west slopes of the Cascades with 2-10" for the east slopes of the Cascades. Snow-to-water ratios will be high, particularly behind the front.

Expect another 2-6" of snow for the west slopes of the Cascades as an offshore low digs off the coast of Oregon and spins bands of moisture northward. E winds around the low and at low levels should allow for accumulations along the E slopes of the Cascades. The offshore low drifts toward the mouth of the Columbia River and with light banded snow showers continue to add low density snow across the region.