We're in for a quiet weather day as a broad upper level trough pulls away from our area and an upper ridge of high pressure over British Columbia nudges closer to our area today. Mostly sunny skies and breezy N-NW ridgeline winds will sum up the forecast for most areas today with freezing levels rising into the 5000-6000' range. There should be a few afternoon cumulus clouds that build up along the west slopes of the Cascades and Passes in the afternoon, along with some lower clouds near northeast WA Cascades.
A mostly clear Thursday night will give way to a sunny start on Friday. The upper level ridge will move over the PNW on Friday but begin to flatten. A frontal boundary will shift closer to our area on Friday, slipping over Vancover Island and southern B.C. This should cause some filtered sunshine in the afternoon as high clouds drift over the area, perhaps thicker over the Olymipcs and northern Cascades. Freezing levels should be slightly warmer on Friday, rising to 5500-6500' in the afternoon. Breezy NW ridgeline winds will continue through Friday.
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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Thursday
Mostly sunny. Light to moderate ridgeline winds.
Thursday
Night
Mostly clear. Light to moderate ridgeline winds.
Thursday
Mostly sunny. Light to moderate ridgeline winds.
Thursday
Night
Mostly clear. Light to moderate ridgeline winds.
Thursday
Mostly sunny with a few afternoon clouds near ridgetop. Light to moderate ridgeline winds.
Thursday
Night
Mostly clear. Light to moderate ridgeline winds.
Thursday
Mostly sunny with a few afternoon clouds near ridgetop. Light to moderate ridgeline winds.
Thursday
Night
Mostly clear. Light to moderate ridgeline winds.
Thursday
Mostly sunny with a few afternoon clouds near ridgetop. Light to moderate N then NW ridgeline winds. Light W winds at Pass level increasing in the afternoon.
Thursday
Night
Mostly clear. Light to moderate NW ridgeline winds and W winds at Pass level.
Thursday
Mostly sunny with a few afternoon clouds near ridgetop. Light to moderate N then NW ridgeline winds. Light W winds at Pass level increasing in the afternoon.
Thursday
Night
Mostly clear. Light to moderate NW ridgeline winds and W winds at Pass level.
Thursday
Partly to mostly sunny in the morning, cloudier near and north of Hwy20, then mostly sunny in the afternoon. Moderate ridgeline winds.
Thursday
Night
Mostly clear. Light to moderate ridgeline winds.
Thursday
Mostly sunny. Light to moderate ridgeline winds.
Thursday
Night
Mostly clear. Light to moderate ridgeline winds.
Thursday
Mostly sunny. Light to moderate ridgeline winds.
Thursday
Night
Mostly clear. Light to moderate ridgeline winds.
Thursday
Mostly sunny with a few afternoon 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).