An upper level ridge of high pressure will shift inland and into eastern Washington today with a mild and dry day on tap. Areas of low clouds near and west of the Cascade crest are shallow. If you're on one of the volcanoes or higher peaks, you should be able to see get above the clouds above 6,000' or so. Low clouds will break up this morning but are unlikely to completely dissipate for areas west of the Cascade crest, expect scattered stratocumulus in the afternoon. Sunnier skies can be found in areas not contending with low clouds. An approaching frontal system will slowly spread high clouds inland today. While this higher level moisture won't have much effect on inland areas, the Olympics may see more of a light overcast and filtered sunshine sky.
A weak front will approach the coast overnight. The front will pass through the Cascades during the late morning, with light rain and snow spreading over the central Cascades. Snow levels will drop rapidly to 4000' by sunrise on Wednesday. There should be a burst of moderate southerlies out ahead of the front for the usual locations like Hurricane Ridge and the Mt Baker area. Post-frontal showers will begin Wednesday afternoon and continue Wednesday night. A Puget Sound Convergence Zone may produce up to 6" of snow through Wednesday morning between the Mt Loop and Snoqualmie Pass. Lighter snowfall amounts are expected elsewhere.
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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Tuesday
Partly sunny. Areas of low clouds this morning. Becoming mostly cloudy in the afternoon with increasing high clouds.
Tuesday
Night
Cloudy with light rain or snow developing late. Ridgeline winds increasing and becoming moderate after midnight.
Tuesday
Mostly sunny with areas of low clouds. Becoming partly to mostly sunny with high clouds increasing in the afternoon.
Tuesday
Night
Cloudy with light rain or snow developing late. Ridgeline winds increasing and becoming moderate to strong after midnight.
Tuesday
Mostly sunny with areas of low clouds. Becoming partly to mostly sunny with high clouds increasing in the afternoon.
Tuesday
Night
Cloudy with a chance of light rain or snow late. Ridgeline winds increasing and becoming moderate after midnight.
Tuesday
Mostly sunny with areas of low clouds. Becoming partly to mostly sunny with high clouds increasing in the afternoon.
Tuesday
Night
Cloudy.
Tuesday
Mostly sunny with areas of low clouds. Becoming partly to mostly sunny with high clouds increasing in the afternoon. Light west winds at Pass level.
Tuesday
Night
Cloudy with a chance of light rain or snow late. Light west winds at Pass level.
Tuesday
Mostly sunny with areas of low clouds. Becoming partly to mostly sunny with high clouds increasing in the afternoon. Light west winds at Pass level.
Tuesday
Night
Cloudy with a chance of light rain or snow late. Light west winds at Pass level.
Tuesday
Mostly sunny. Increasing high clouds in the afternoon.
Tuesday
Night
Cloudy.
Tuesday
Mostly sunny. Increasing high clouds in the afternoon.
Tuesday
Night
Cloudy. Ridgeline winds increasing and becoming moderate after midnight.
Tuesday
Mostly sunny. Increasing high clouds in the afternoon.
Tuesday
Night
Cloudy. Ridgeline winds increasing and becoming moderate after midnight.
Tuesday
Mostly sunny with areas of low clouds. Becoming partly to mostly sunny with high clouds increasing in the afternoon.
Tuesday
Night
Cloudy. Ridgeline winds increasing and becoming moderate after midnight.
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).