A weak system fizzles along the Canadian border Thursday morning as it rounds the top of a flattening ridge. The remnants of the system will bring some moderate ridgeline winds to the northern portions of the Cascades from Mt Baker, to Washington Pass, and Mission Ridge. These winds should ease as the day progresses. The system will also bring a mid-level cloud deck to the Olympic northern Cascades in the morning hours with a slight chance of showers for the southern Olympics. Clouds dissipating in the afternoon hours. Other areas should experience mostly sunny skies. Freezing levels remain unseasonably high, ranging from 8000-9000 ft in the north to 10500-11500 ft around Mt Hood. Weak low-level E flow should keep the passes slightly cooler, but these winds could temporarily switch W in the mid-day hours.
Thursday night will bring mostly clear skies, light SW winds at the ridgeline, and very light low-level E winds. Inversions around Washington Pass will not be as sharp as Wednesday night.
Friday will bring mostly sunny skies as the ridge rebounds over the intermountain west. Light winds and 8000-10500 ft freezing levels should make for another spring-like day in the mountains.
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 in the morning with a few showers in the southern Olympics, then becoming mostly sunny in the afternoon. Decreasing light to moderate ridgeline winds.
Thursday
Night
Mostly clear skies.
Thursday
Mostly cloudy in the morning with a stray shower possible, then becoming mostly sunny in the afternoon. Decreasing light to moderate ridgeline winds. Moderate ridgeline winds become light in the afternoon.
Thursday
Night
Mostly clear skies.
Thursday
Partly cloudy in the morning, then becoming mostly sunny.
Thursday
Night
Mostly clear skies.
Thursday
Mostly sunny.
Thursday
Night
Mostly clear skies.
Thursday
Mostly sunny with some mid-level clouds possible in the morning. Mostly light ridgeline and E wind at the Pass.
Thursday
Night
Mostly clear skies. Light ridgeline and E wind at the Pass.
Thursday
Mostly sunny with some mid-level clouds possible in the morning. Mostly light ridgeline and E wind at the Pass.
Thursday
Night
Mostly clear skies. Light ridgeline and E wind at the Pass.
Thursday
Mostly sunny with a few high clouds. Decreasing moderate ridgeline winds.
Thursday
Night
Mostly clear skies.
Thursday
Mostly sunny with a few high clouds. Decreasing moderate ridgeline winds.
Thursday
Night
Mostly clear skies.
Thursday
Mostly sunny with a few high clouds. Decreasing moderate ridgeline winds.
Thursday
Night
Mostly clear skies.
Thursday
Mostly sunny. Decreasing light to moderate 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).