Precipitation associated with an ill-defined warm frontal feature coming over the top of an upper level ridge positioned offshore will continue mainly along the west slopes of the Cascades and Olympics through mid-day and then taper off during the afternoon. Unfortunately, the precipitation associated with this system has been underwhelming, and storm totals through Thursday afternoon have been downgraded to the 2-7" range, with less snow further east of the Cascade crest and down near Mt. Hood. As the moisture tap dries up later this morning, precipitation could become more drizzly/misty in nature along the west slopes of the Cascades. Snow levels will continue to slowly rise during the day as milder air works into the region.
We'll see a break in the precipitation tonight and early tomorrow except where very light rain and snow lingers for the northwest Cascades. A fast moving frontal system will swing through from the NW on Friday, spreading precipitation southward during the daylight hours. More moderate precipitation and snowfall rates can be expected in the Mt Baker area in the afternoon with lighter snowfall amounts just about everywhere else. Look for a sharp uptick in winds tomorrow afternoon ahead and behind the front Friday afternoon. Snow levels will fall to 3000-4000' with the onset of precipitation. Snoqualmie Pass will be right on the edge of the rain/snow line Friday.
Weather Forecast
Olympics
West North
West Central
West South
Stevens Pass
Snoqualmie Pass
East North
East Central
East South
Mt. Hood
Use dropdown to select your zone
Thursday
Cloudy with periods of light rain and snow tapering off in the afternoon.
Thursday
Night
Cloudy.
Thursday
Cloudy with periods of light rain and snow.
Thursday
Night
Cloudy with periods of light rain and snow.
Thursday
Cloudy with periods of light rain and snow tapering off in the afternoon.
Thursday
Night
Cloudy.
Thursday
Cloudy with light to occasionally moderate rain and snow tapering off mid-day.
Thursday
Night
Mostly cloudy.
Thursday
Cloudy with periods of light rain and snow tapering off in the afternoon. Light west winds at Pass level.
Thursday
Night
Mostly cloudy. Light east winds at Pass level.
Thursday
Cloudy with light to occasionally moderate rain and snow tapering off mid-day. Light west winds at Pass level.
Thursday
Night
Mostly cloudy. Light east winds at Pass level.
Thursday
Cloudy with periods of light snow near the Cascade crest tapering off mid-day.
Thursday
Night
Mostly cloudy.
Thursday
Cloudy with periods of light snow near the Cascade crest tapering off mid-day. Strong ridgeline winds decreasing in the afternoon.
Thursday
Night
Mostly cloudy.
Thursday
Cloudy with periods of light snow near the Cascade crest tapering off mid-day.
Thursday
Night
Mostly cloudy.
Thursday
Cloudy with periods of light snow, mainly south and west sides of the mountain, tapering off mid-day. Partly to mostly cloudy in the afternoon, especially east side.
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).