An E-W oriented frontal boundary will largely stay stalled to our north today and tonight, leaving us with a dry day. A cool breeze from the offshore easterly flow in the Passes will abate by early afternoon as westerly onshore flow takes over. This will also allow freezing levels to pop this afternoon, warmest in the south over Mt Hood near (10,000'), and coolest over the Olympics and north Cascades closer to the boundary (5500'/6000'). Clouds will be thicker over the northern Olympics and Cascades this morning and clearer to the south. High clouds will begin to filter in from the SW during the afternoon, creating filtered sunshine for most areas.
A broad upper level trough over the NE Pacific will exert more influence over our weather as we head into the weekend. Look for freezing levels to slowly drop late Friday night and Saturday, and be accompanied by an influx of mid and high clouds, and an uptick in moderate westerly winds. There's a chance for light rain and snow showers to reach the Mt Baker area by Saturday afternoon, otherwise conditions will remain dry.
The trough will bring another dip in freezing levels/temperatures and and showers inland on Sunday.
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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Friday
Mostly cloudy. Light to occasionally moderate ridgeline winds.
Friday
Night
Mostly cloudy. Light to occasionally moderate ridgeline winds.
Friday
Mostly cloudy. Light to moderate ridgeline winds.
Friday
Night
Mostly cloudy. Light to moderate ridgeline winds.
Friday
Partly to mostly sunny in the morning, then partly to mostly cloudy in the afternoon with filtered sunshine. Light to occasionally moderate ridgeline winds.
Friday
Night
Mostly cloudy with high clouds. Light to moderate ridgeline winds.
Friday
Mostly sunny in the morning, then partly to mostly cloudy in the afternoon with filtered sunshine. Moderate ridgeline winds becoming lighter in the afternoon.
Friday
Night
Mostly cloudy with high clouds. Light to moderate ridgeline winds.
Friday
Partly to mostly sunny in the morning, then partly to mostly cloudy in the afternoon with filtered sunshine. Light to moderate SE ridgeline winds becoming light SW in the afternoon. Light E winds at Pass level becoming W in the afternoon.
Friday
Night
Mostly cloudy with high clouds. Light to moderate ridgeline winds.
Friday
Mostly sunny in the morning, then partly to mostly cloudy in the afternoon with filtered sunshine. Moderate SE ridgeline winds becoming light SW in the afternoon. Light to moderate E winds at Pass level becoming light W in the afternoon.
Friday
Night
Mostly cloudy with high clouds. Light to moderate W ridgeline and Pass level winds.
Friday
Partly to mostly cloudy with high clouds and filtered sunshine. Light to moderate ridgeline winds.
Friday
Night
Mostly cloudy with high clouds. Light to moderate W ridgeline and Pass level winds.
Friday
Mostly sunny in the morning, then partly to mostly cloudy in the afternoon with filtered sunshine. Light to occasionally moderate ridgeline winds.
Friday
Night
Mostly cloudy with high clouds. Light to moderate ridgeline winds.
Friday
Mostly sunny in the morning, then partly sunny in the afternoon with periods of filtered sunshine. Light to occasionally moderate ridgeline winds.
Friday
Night
Partly to mostly cloudy with high clouds. Light to moderate ridgeline winds.
Friday
Mostly sunny in the morning, then partly sunny in the afternoon with periods of filtered sunshine. Light to occasionally moderate ridgeline winds.
Friday
Night
Partly to mostly cloudy with high clouds. 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).