Mountain Weather Forecast

Weather Synopsis

The Pacific Northwest is entering a short-duration, but extremely intense cold-air outbreak through the weekend. A deep upper low and surface high over Alberta Canada has spawned and pushed a modified arctic through northern Washington State that will continue to progress to around the Washington/Oregon border overnight. The passage of this front eases a period of gusty W (moderate to locally strong W or WNW winds) through the evening hours. Most areas of the central and southern Washington Cascades can expect less than 3" of additional snow in banded showers for areas south of Highway 2 during the evening hours before snow showers taper to flurries. Mt St Helens and Mt Adams could pick up 3-6". Plummeting temperatures will be the other major story with temperatures dropping below zero in many areas. Temperatures may rise only into the single digits or teens in many areas on Friday as cold NW flow continues. Increasing wind chills associated with strengthening E winds peak early Saturday. Expect the coldest temperatures and most dangerous windchills (-20 to -30F windchills) late Friday night and early Saturday. Winds and temperatures gradually start to ease as the day progresses but don't expect high temperatures to get out of the single digits in some areas. The coldest temperatures will be east of the Cascades.

Mt Hood will have quite different weather from Washington State with significant additional snowfall. Expect very heavy snow and strong to extreme WNW winds to be most intense on the east side of the mountain. Ridgeline winds and snow showers decrease into the moderate range by Friday. Steadier light to moderate snow increases Friday night with more moderate to heavy snow as a low approaches the Oregon coast on Saturday. Snowfall amounts through Saturday should be in the 1-2.5 ft range.