Friday will be a transition day from a cold, snowy pattern to a progressively milder one. The upper trough axis that moved through Thursday morning continues to slide eastward as a ridge moves from the west. NW winds aloft continue to ease along as moderate ridgeline winds, focusing on several areas near and east of the Cascade Crest, generally shift into the light range during the morning hours. By 7 AM, most of the snow shower activity along the west slopes of the Cascades has transitioned to snow flurries over the Cascades; however, a few snow showers are visible on moving NNE over the western Olympics, guided by an approaching warm front. As the day progresses, expect increasing filtered sunshine with cloud cover lingering much longer into the afternoon for the Mountain Loop and Mt Baker areas.
High clouds continue to move into the area Friday night as temperatures continue to moderate on gradually increasing SW winds.
A warm, wet frontal system gradually moves ESE into the region on Saturday. It will begin impacting the Olympics in the morning, then Mt Baker and perhaps the Mountain Loop in the afternoon. Snow levels will rise to 4000-5000 ft in the Olympics. Although temperatures may rise above freezing Saturday morning in the Mt Baker area, the precipitation should lower snow levels to 4000-4500 ft as it moves into the area in the afternoon. SSW winds are likely to increase into the moderate range for favored areas around Mt Baker, with strong gusts likely.
Weather Forecast
Olympics
West North
West Central
West South
Stevens Pass
Snoqualmie Pass
East North
East Central
East South
Mt. Hood
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Friday
Partly cloudy in the morning with filtered sunshine in the afternoon. Mild.
Friday
Night
High clouds lower and thicken.
Friday
Cloudy with a few light snow showers or flurries through the mid-day hours. Skies become partly to mostly cloudy in the afternoon.
Friday
Night
High clouds. Increasing moderate ridgeline winds.
Friday
Cloudy with a few light snow showers or flurries through the mid-day hours. Skies become partly cloudy in the afternoon.
Friday
Night
High clouds.
Friday
A few snow flurries early, then clearing skies with filtered sunshine.
Friday
Night
High clouds.
Friday
A few flurries early, then gradual clearing with partly cloudy skies and filtered sunshine by the afternoon. Moderate ridgeline winds quickly become light. Light W winds at the Pass.
Friday
Night
High clouds. Light ridgeline and E wind at the Pass.
Friday
A few flurries early, then gradual clearing with partly cloudy skies and filtered sunshine by the afternoon. Light ridgeline and W wind at the Pass becomes variable late in the day.
Friday
Night
High clouds. Light ridgeline and E wind at the Pass.
Friday
A few flurries early in the day, giving way to filtered sunshine. Decreasing light to moderate ridgeline winds.
Friday
Night
High clouds.
Friday
A few flurries early in the day, giving way to filtered sunshine. Decreasing light to moderate ridgeline winds.
Friday
Night
High clouds.
Friday
Partly cloudy in the morning, giving way to filtered sunshine.
Friday
Night
Thin high clouds.
Friday
A few lingering clouds early, then filtered sunshine.
The NWAC program is administered by the USDA-Forest Service and operates from the National Weather Service Forecast Office in Seattle. NWAC services are made possible by important collaboration and support from a wide variety of federal, state and private cooperators.
The 5000’ temperature forecast does not imply a trend over the 12 hr period and only represents the max and min temperatures within a 12 hr period in the zone. The 6-hr snow level forecast, the forecast discussion, and weather forecast sections may add detail regarding temperature trends.
The snow level forecast represents the general snow level over a 6 hr time period. Freezing levels are forecast when precipitation is not expected.
*Easterly or offshore flow is highlighted with an asterisk when we expect relatively cool east winds in the major Cascade Passes. Easterly flow will often lead to temperature inversions and is a key variable for forecasting precipitation type in the Cascade Passes. Strong easterly flow events can affect terrain on a more regional scale.
Ridgeline winds are the average wind speed and direction over a 6 hr time period.
The wind forecast represents an elevation range instead of a single elevation slice. The elevation range overlaps with the near and above treeline elevation bands in the avalanche forecast and differs per zone.
Wind direction indicates the direction the wind originates or comes from on the 16-point compass rose.
Water Equivalent (WE) is the liquid water equivalent of all precipitation types; rain, snow, ice pellets, etc., forecast to the hundredth of an inch at specific locations. To use WE as a proxy for snowfall amounts, start with a snow to water ratio of 10:1 (10 inches of snow = 1 inch WE). Temperatures at or near freezing will generally have a lower ratio (heavy wet snow) and very cold temperatures can have a much higher ratio (dry fluffy snow).