The lingering surface low-pressure center moves onshore and dissipates over central British Columbia. The associated upper-level trough has shifted winds westerly and the air mass remains unstable. Slightly cooler temperatures have shifted the snow level down to around 3000 ft where it should remain most of the day throughout the region. Snow showers and convergence continue to add accumulating snow to the west slopes of the Cascades with higher snow totals in the north. Dualling convergence bands will focus the heavier shower activity on Whatcom and Skagit Counties (with some spillover to Washington Pass) during the morning hours with another band over the southern mountain loop. During the late afternoon and evening, flow switches to the WNW and Puget Sound convergence should shift southward through Stevens and Snoqualmie Passes.
Mt. Baker can expect 6-10" of snow by the end of the day, while the mountain loop and Stevens passes might pick up 3-6". Other areas can expect lesser amounts with skies partially clearing along the east slopes of the Cascades.
The trough lingers Saturday evening with decreasing light snow showers, tapering overnight as a ridge of high pressure builds into the region. The ridge of high pressure moves in on Sunday. Temperatures should be near normal with shallow low cloud west of the Cascades and mostly sunny skies to the east.
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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Saturday
Decreasing very light snow showers with partly to mostly cloudy skies from late morning onwards.
Saturday
Night
Partly cloudy.
Saturday
Heavy snow in the morning, tapering to moderate snow showers.
Saturday
Night
Decreasing light snow showers.
Saturday
Moderate snow showers, heaviest in convergence bands.
Saturday
Night
Light snow showers and convergence.
Saturday
Light snow showers, heaviest at Paradise. Crystal largely blocked. Strong ridgeline winds continue through the morning at White Pass.
Saturday
Night
Very light snow showers tapering to flurries.
Saturday
Light snow showers and moderate convergence. Decreasing light to moderate ridgeline and light W wind at the Pass.
Saturday
Night
Light snow showers and convergence decreasing or ending overnight. Light ridgeline and W wind at the Pass.
Saturday
Light snow showers and moderate convergence. Decreasing moderate ridgeline and light W wind at the Pass.
Saturday
Night
Light snow showers and moderate convergence in the evening, tapering overnight. Decreasing light ridgeline and W wind at the Pass.
Saturday
Light to occasionally moderate snow with convergence during the morning hours, tapering to snow flurries in the afternoon.
Saturday
Night
Mostly cloudy with a few snow flurries in the evening, then mostly clear overnight.
Saturday
Decreasing light snow showers near the Cascade Crest.
Saturday
Night
A few snow flurries near the Cascade Crest in the evening, then becoming partly cloudy.
Saturday
Very light snow showers near the Cascade Crest.
Saturday
Night
Partly cloudy.
Saturday
Decreasing light snow showers.
Saturday
Night
A few snow flurries in the evening, then partly cloudy.
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).