Following a snowy few days and a cold start to Wednesday morning (mountain temperatures in the teens and 20s), we'll flip the winter-time script with significant warming today, tonight, and Thursday. An upper level ridge of high pressure will move over the area today and inland on Thursday leaving us with dry weather. With a frontal boundary hung up well north of the area and positioned over B.C.'s Sunshine Coast, there's some question to how much high clouds will impact an otherwise dry forecast over the next 36 hours.
For this afternoon and evening, the Olympics and the northwest Cascades including the Mt Baker area may see thicker high clouds, while other areas see occasional filtered sunshine. High clouds will stick with us later tonight and Thursday, but may be less of a factor. Freezing levels and temperatures will begin their upward trajectory today, continuing overnight, and reach 9000-12000' on Thursday along with 5000' temperatures generally in the 50s. The East North zone including Washington Pass, will be relatively cooler, but will see the same trend over time.
Finally, offshore easterly gradients and the frontal system offshore will help keep a light but consistent S-SE breeze in 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 in the morning, becoming partly sunny in the afternoon with increasing high clouds and periods of filtered sunshine.
Wednesday
Night
Partly cloudy with periods of high clouds.
Wednesday
Mostly sunny in the morning, becoming partly sunny in the afternoon with increasing high clouds and periods of filtered sunshine.
Wednesday
Night
Partly cloudy with periods of high clouds.
Wednesday
Mostly sunny in the morning with increasing high clouds in the afternoon.
Wednesday
Night
Partly cloudy with periods of high clouds.
Wednesday
Mostly sunny in the morning with increasing high clouds in the afternoon.
Wednesday
Night
Partly cloudy with periods of high clouds.
Wednesday
Mostly sunny in the morning with increasing high clouds in the afternoon. Light east winds at Pass level.
Wednesday
Night
Partly cloudy with periods of high clouds. Light to moderate east winds at Pass level.
Wednesday
Mostly sunny in the morning with increasing high clouds in the afternoon. Light east winds at Pass level.
Wednesday
Night
Partly cloudy with periods of high clouds. Moderate east winds at Pass level.
Wednesday
Mostly sunny in the morning with increasing high clouds in the afternoon.
Wednesday
Night
Partly cloudy with periods of high clouds.
Wednesday
Mostly sunny in the morning with increasing high clouds in the afternoon.
Wednesday
Night
Partly cloudy with periods of high clouds.
Wednesday
Mostly sunny in the morning with increasing high clouds in the afternoon.
Wednesday
Night
Partly cloudy with periods of high clouds.
Wednesday
Mostly sunny in the morning with increasing high clouds 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).