A weak frontal system pushed into B.C. overnight, glancing the PNW with very light precipitation (mostly rain below 5000') along the west slopes of the Cascades. This system also produced moderate to strong NW ridgeline winds in many areas. High pressure anchored offshore will exert its influence over the region today and skies will be mostly sunny in the afternoon along with high freezing levels/mild mountain temperatures. Low clouds along the west slopes of the Cascades and Stevens/Snoqualmie Passes will mostly scatter out except in the north Cascades where low level moisture will hang on a bit longer. There will be a slow decrease in wind speeds during the day.
There won't be much change in the pattern through Thursday. Low clouds ringing the Olympics and along the foothills of the Snohomish through Whatcom county will ebb and flow with clearer conditions elsewhere. Barlow Pass/Mt Baker area could see a few drips tonight or tomorrow as a dry upper level weather feature swings through tomorrow. This feature will also increase NW ridgeline winds once again on late Wednesday night through Thursday. Freezing levels will stay pegged between 10,000-12,000 for most areas over the short term.
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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Wednesday
Mostly sunny with areas of low clouds. Moderate to strong ridgeline winds.
Wednesday
Night
Partly to mostly cloudy.
Wednesday
Mostly cloudy with a chance of light rain or snow in the morning. Becoming partly to mostly cloudy in the afternoon. Moderate ridgeline winds.
Wednesday
Night
Mostly cloudy.
Wednesday
Mostly cloudy with a chance of light rain or snow in the morning. Becoming partly to mostly cloudy in the afternoon. Moderate to strong ridgeline winds.
Wednesday
Night
Mostly cloudy.
Wednesday
Mostly sunny except for some low clouds western part of the zone this morning. Moderate to strong ridgeline winds.
Wednesday
Night
Mostly clear.
Wednesday
Mostly cloudy with a chance of light rain or snow in the morning. Becoming partly to mostly cloudy in the afternoon. Light west winds at Pass level. Moderate to strong ridgeline winds decreasing in the afternoon.
Wednesday
Night
Partly cloudy. Light west winds at Pass level.
Wednesday
Mostly cloudy with a chance of light rain or snow in the morning. Becoming partly to mostly cloudy in the afternoon. Light west winds at Pass level. Moderate to strong ridgeline winds decreasing in the afternoon.
Wednesday
Night
Partly cloudy. Light west winds at Pass level.
Wednesday
Mostly cloudy this morning. Becoming partly to mostly cloudy in the afternoon, sunnier further east of the Cascade crest. Moderate to strong ridgeline winds this morning decreasing in the afternoon.
Wednesday
Night
Partly cloudy. Moderate to strong ridgeline winds increasing overnight.
Wednesday
Partly to mostly cloudy this morning. Becoming partly to mostly sunny in the afternoon, sunnier further east of the Cascade crest. Moderate to strong ridgeline winds this morning decreasing in the afternoon.
Wednesday
Night
Mostly clear. Moderate to strong ridgeline winds increasing overnight.
Wednesday
Mostly sunny. Moderate to strong ridgeline winds this morning decreasing in the afternoon.
Wednesday
Night
Mostly clear.
Wednesday
Mostly sunny. Moderate to strong ridgeline winds this morning decreasing in the afternoon.
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).