A quick moving frontal system passed through last night bringing 24 hr snowfall totals of 6-12" along the west slopes of the Cascades (15" locally at Mt Baker) and 2-5" along the east slopes of the Cascades and Mt Hood. Scattered snow showers and a dissipating Puget Sound Convergence zone will continue to wring out some snow showers this morning, mainly along the west slopes of the Cascades. Moderate to locally strong post-frontal NW ridgeline winds will slowly decrease Thursday afternoon as well.
A ridge of high pressure will nose into central/south British Columbia this afternoon. While this will cement our drying trend, expect periods of high clouds to float on down over the ridge today and Thursday night. Subsidence, or sinking air associated with the high pressure system, will also prevent a full clearing trend west of the Cascade crest by trapping some clouds/moisture below the higher peaks.
On Friday, high pressure will move over the west coast. We should be in for a dry day with a modest bump in temperatures/freezing levels versus Thursday. We should see mostly sunny skies with some uncertainty regarding how many high clouds try to slip under the ridge tomorrow.
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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Thursday
Partly sunny with a mix of low and high clouds.
Thursday
Night
Partly to mostly clear. Periods of high clouds.
Thursday
Mostly cloudy this morning with a chance of light snow showers. Then partly sunny with a mix of low and high clouds.
Thursday
Night
Partly to mostly clear. Periods of high clouds.
Thursday
Cloudy this morning with light snow showers. Then partly sunny with a mix of low and high clouds. Moderate ridgeline winds decreasing in the afternoon.
Thursday
Night
Partly to mostly clear. Periods of high clouds.
Thursday
Mostly cloudy this morning with scattered light snow showers. Then partly sunny with a mix of low and high clouds. Moderate ridgeline winds decreasing in the afternoon.
Thursday
Night
Partly to mostly clear. Periods of high clouds.
Thursday
Cloudy this morning with scattered light snow showers. Then partly sunny with a mix of low and high clouds. Moderate Pass level and ridgeline W-NW winds decreasing in the afternoon.
Thursday
Night
Partly to mostly clear. Periods of high clouds.
Thursday
Cloudy this morning with light snow showers. Then partly sunny with a mix of low and high clouds. Moderate Pass level and ridgeline W-NW winds decreasing in the afternoon.
Thursday
Night
Partly to mostly clear. Periods of high clouds.
Thursday
Partly cloudy with isolated snow showers near the Cascade crest this morning, then mostly sunny. Moderate ridgeline winds decreasing in the afternoon.
Thursday
Night
Partly to mostly clear. Periods of high clouds.
Thursday
Partly cloudy with isolated snow showers near the Cascade crest this morning, then mostly sunny. Moderate to strong ridgeline winds decreasing in the afternoon.
Thursday
Night
Partly to mostly clear. Periods of high clouds.
Thursday
Partly cloudy with isolated snow showers near the Cascade crest this morning, then mostly sunny. Moderate ridgeline winds decreasing in the afternoon.
Thursday
Night
Partly to mostly clear. Periods of high clouds.
Thursday
Partly cloudy with isolated snow showers this morning, then mostly sunny. Moderate to strong ridgeline winds decreasing in the afternoon.
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).