9:07 AM: Corrected an error in the Olympic sensible weather
This weekend promises to be unusually warm and dry. A high pressure amplifying slightly over the region fends off a dissipating frontal system just north of the Canadian border. Meanwhile, a broad upper low spins off the California coastline. Expect some high clouds over the region today resulting from these two features Ridgeline winds will be westerly through the weekend as flow rounds the top of the ridge. However, on the eastern slopes of the Cascades, low clouds linger, moving through the Cascade Passes due to a continuous low-level easterly wind. These W winds should help dry out the middle elevations E of the Cascade Crest which had been slow to dry out in the recent pattern. However, E flow remains throughout the weekend at low levels with low-level status likely streaming through the lower gaps such as Snoqualmie Pass.
Freezing levels are high throughout the forecast period with most areas ranging from 7000-10000 ft. Washington Pass will experience multiple freezing levels with cold temperatures right a pass level. An isolated upper-level low off the California coast will bring high cloud bands over the region from tonight until Sunday, resulting in periods of sunshine filtered through the clouds during the day. This weather system will move closer on Sunday, potentially increasing cloud cover later in the day.
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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Saturday
Filtered sunshine and mostly thin high clouds. Mild. Light ridgeline winds.
Saturday
Night
Mostly clear with some thin high clouds. Mild. Light ridgeline winds.
Saturday
Filtered sunshine and mostly thin high clouds. Mild. Light ridgeline winds.
Saturday
Night
Mostly clear with some thin high clouds. Mild. Light ridgeline winds.
Saturday
Filtered sunshine and mostly thin high clouds. Mild. Light ridgeline winds.
Saturday
Night
Mostly clear with some thin high clouds. Mild. Light ridgeline winds.
Saturday
Filtered sunshine and mostly thin high clouds. Mild. Light ridgeline winds. Moderate E winds near the mountain gaps.
Saturday
Night
Mostly clear with some thin high clouds. Mild. Light ridgeline winds.
Saturday
Filtered sunshine and mostly thin high clouds. Multiple freezing levels at times. Light ridgeline winds. Light E wind at the Pass.
Saturday
Night
Filtered sunshine and mostly thin high clouds. Multiple freezing levels at times. Light ridgeline winds. Light E wind at the Pass.
Saturday
Filtered sunshine and mostly thin high clouds. Multiple freezing levels at times. Light to moderate ridgeline winds. Light to moderate E wind at the Pass.
Saturday
Night
Mostly clear with some thin high clouds. Multiple freezing levels. Light to moderate ridgeline winds. Light to moderate E wind at the Pass.
Saturday
Filtered sunshine and mostly thin high clouds. Mild. Light ridgeline winds. Multiple freezing levels.
Saturday
Night
Mostly clear with some thin high clouds. Mild. Light ridgeline winds. Multiple freezing levels.
Saturday
Filtered sunshine and mostly thin high clouds. Mild. Light ridgeline winds.
Saturday
Night
Mostly clear with some thin high clouds. Mild. Light ridgeline winds.
Saturday
Filtered sunshine and mostly thin high clouds. Mild. Light ridgeline winds.
Saturday
Night
Mostly clear with some thin high clouds. Mild. Light ridgeline winds.
Saturday
Filtered sunshine and mostly thin high clouds. Mild. Light ridgeline winds.
Saturday
Night
Mostly clear with some thin high clouds. Mild. Light 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).