A ridge of high pressure will continue to slowly slide east today with high clouds spilling over the top of the ridge into our area. Areas further south of I-90 will be mostly sunny this morning with partly sunny/filtered sun further north. High clouds should increase this afternoon for all areas. Mid and upper level temperatures are already above freezing in many areas and we can expect to find high freezing levels near and west of the Cascade crest. Colder air along the east slopes of the Cascades will make for temperature inversions with uncertainty surrounding if above-freezing air will punch in above 5000' or so. Moderate to strong southerly winds will continue to affect areas like Mt Baker, Hurricane Ridge and Crystal Mt ahead today.
As a weak frontal system approaches the coast Thursday night we can expect increasing high clouds and increasing offshore flow. This should help drag colder air back towards the Cascade crest and through the Cascade gaps, setting up inversions and generally messing freezing levels near and east of the Cascade crest along with windy conditions.
The front itself will push inland Friday afternoon and is unimpressive regarding precipitation amounts. Look for falling snow levels with the onset of precipitation mid-day and early afternoon. The Mt Baker area should see a few inches of snow will less rain and snow elsewhere through Friday afternoon.
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
Mostly cloudy with periods of filtered sunshine. Moderate to strong ridgeline winds.
Thursday
Night
Cloudy. Strong ridgeline winds.
Thursday
Partly sunny in the morning then mostly cloudy with filtered sunshine. Moderate to strong ridgeline winds.
Thursday
Night
Cloudy. Strong ridgeline winds.
Thursday
Partly sunny in the morning then mostly cloudy with filtered sunshine.
Thursday
Night
Cloudy. Moderate ridgeline winds.
Thursday
Mostly sunny in the morning then partly sunny in the afternoon with filtered sunshine. Moderate to strong ridgeline winds.
Thursday
Night
Cloudy. Strong ridgeline winds.
Thursday
Partly sunny in the morning then mostly cloudy with filtered sunshine. Light to Moderate Easterly Pass level and ridgeline winds.
Thursday
Night
Cloudy. Moderate E-SE Pass level and ridgeline winds.
Thursday
Partly sunny in the morning then mostly cloudy with filtered sunshine. Moderate Easterly Pass level and ridgeline winds.
Thursday
Night
Cloudy. Moderate to strong E-SE Pass level and ridgeline winds.
Thursday
Partly sunny in the morning then mostly cloudy with filtered sunshine.
Thursday
Night
Mostly cloudy. Moderate ridgeline winds.
Thursday
Mostly sunny in the morning then partly sunny in the afternoon with filtered sunshine. Moderate ridgeline winds.
Thursday
Night
Mostly cloudy. Moderate ridgeline winds.
Thursday
Mostly sunny in the morning then partly sunny in the afternoon with filtered sunshine.
Thursday
Night
Mostly cloudy. Moderate ridgeline winds.
Thursday
Mostly sunny in the morning then partly sunny in the afternoon with filtered sunshine. Moderate ridgeline winds.
Thursday
Night
Mostly cloudy. Moderate to strong ridgeline winds.
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).