A weak upper level shortwave passed through the region last night bringing some very light precipitation (likely an inch or less of snow) to the west slopes of the Cascades and Passes along with falling temperatures. The flow aloft is becoming northerly and it quickly ushering in a clearing trend with much drier air moving in at all areas. We'll see low clouds hang on this morning along the west slopes of the Cascades near and south of Hwy 2 to Mt Hood (and along the northern slopes of the Olympics) before joining the rest of the region in mostly sunny skies. Look for brisk NE ridgeline winds, strongest near the Canadian border today. After a cool start, freezing levels will rebound into the 2500-3500' range today.
Strong upper level ridging will nose over the PNW and British Columbia this weekend while a cold upper level trough digs over California. We should see mostly clear skies on Saturday with a slow warming trend. The coolest temperatures will be in the Passes, along the east slopes of the Cascades and down near Mt Hood closer to the upper low. We'll also see slightly stronger NE ridgeline winds tomorrow in this pattern as well.
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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Friday
Mostly sunny except mostly cloudy north slopes of the Olympics this morning with a chance of light snow. Light to occasionally moderate ridgeline winds.
Friday
Night
Mostly clear. Light to occasionally moderate ridgeline winds.
Friday
Mostly sunny. Light to moderate ridgeline winds.
Friday
Night
Mostly clear. Moderate ridgeline winds.
Friday
Scattered low clouds in the morning with a chance of a flurry, then mostly sunny. Light to occasionally moderate ridgeline winds.
Friday
Night
Mostly clear. Light to occasionally moderate ridgeline winds.
Friday
Mostly cloudy with a chance of a light snow shower in the morning, then mostly sunny in the afternoon. Light to occasionally moderate ridgeline winds.
Friday
Night
Mostly clear. Light to occasionally moderate ridgeline winds.
Friday
Mostly cloudy with a chance of a light snow shower in the morning, then mostly sunny in the afternoon. Light to occasionally moderate NE ridgeline and E Pass level winds.
Friday
Night
Mostly clear. Light to occasionally moderate NE ridgeline and E Pass level winds.
Friday
Mostly cloudy with a chance of a light snow shower in the morning, then mostly sunny in the afternoon. Light to occasionally moderate NE ridgeline and E Pass level winds.
Friday
Night
Mostly clear. Light to occasionally moderate NE ridgeline and E Pass level winds.
Friday
Partly to mostly sunny. Moderate ridgeline winds.
Friday
Night
Mostly clear. Moderate ridgeline winds.
Friday
Mostly sunny except for a few areas of low clouds near the Cascade crest this morning. Light to moderate ridgeline winds.
Friday
Night
Mostly clear. Moderate ridgeline winds.
Friday
Mostly sunny except for a few areas of low clouds near the Cascade crest this morning. Light to moderate ridgeline winds.
Friday
Night
Mostly clear. Moderate ridgeline winds.
Friday
Mostly cloudy this morning becoming mostly sunny. 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).