A flat and dirty ridge of high pressure along the western US will struggle to keep high clouds at bay today. The clouds are the southern dregs of a frontal system aimed well to our north into central/northern British Columbia. While the cloud cover will be variable, mild freezing levels will be a constant today in the 8000-10,000' range. Low level easterly flow will be a hair stronger today, so expect the low clouds currently along the east slopes of the Cascades to hang around and near the Passes, it may take longer to break out. Temperature inversions will be most pronounced near the Passes and along the east slopes of the Cascades again today. In the alpine, moderate to strong WNW winds will occasionally be seen along ridgelines from Snoqualmie Pass and north to the Candian border. This pattern will generally hold Sunday night.
On MLK Day, the frontal system will approach from the NE as the ridge breaks down. Light rain and snow will move into the Olympics and northwest Cascades by the afternoon. Elsewhere, look for continuing periods of high clouds and slowly lowering freezing levels. Specifically, along the west slopes of the Cascades, low clouds should increase late in the day.
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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Sunday
Partly sunny with periods of high clouds and filtered sunshine. Mild.
Sunday
Night
Partly cloudy.
Sunday
Partly sunny with periods of high clouds and filtered sunshine. Mild.
Sunday
Night
Partly cloudy.
Sunday
Partly sunny with periods of high clouds and filtered sunshine. Mild.
Sunday
Night
Partly cloudy.
Sunday
Partly sunny with periods of high clouds and filtered sunshine. Mild.
Sunday
Night
Partly cloudy.
Sunday
Partly sunny with periods of high clouds and filtered sunshine. Mild. Partly sunny with periods of high clouds and filtered sunshine. Mild, except cooler near areas of low clouds and fog. Light east winds at Pass level and moderate NW at ridgeline.
Sunday
Night
Partly cloudy. Areas of low clouds.
Sunday
Partly sunny with periods of high clouds and filtered sunshine. Mild. Partly sunny with periods of high clouds and filtered sunshine. Mild, except cooler near areas of low clouds and fog. Light east winds at Pass level and moderate NW at ridgeline.
Sunday
Night
Partly cloudy. Areas of low clouds.
Sunday
Partly sunny with periods of high clouds and filtered sunshine. Mild, except cooler near areas of low clouds and fog.
Sunday
Night
Partly cloudy. Areas of low clouds.
Sunday
Partly sunny with periods of high clouds and filtered sunshine. Mild, except cooler near areas of low clouds and fog.
Sunday
Night
Partly cloudy. Areas of low clouds.
Sunday
Partly sunny with periods of high clouds and filtered sunshine. Mild, except cooler near areas of low clouds and fog.
Sunday
Night
Partly cloudy. Areas of low clouds.
Sunday
Partly sunny with periods of high clouds and filtered sunshine. Mild.
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).