Thursday features a drying trend as a trough digging to the east of the Cascades yields influence to an offshore high pressure. The northerly flow aloft between these two features continues to bring some strong winds to the south sides of Mt. Hood. Light rain and snow shower activity gradually decreases on low-level WNW flow throughout the day. Expect around 2" of snow for Mt. Hood and an inch at Paradise, with a dusting of snow for the rest of the west slopes of the Cascades and Olympics. Although light to moderate rainfall lingers in the Puget Sound lowlands, much of this moisture doesn't have the lift to ascend the mountain slopes. Low clouds should continue to bank up against the west slopes of the Cascades and filter through the Passes throughout the day. Parts of the Olympics and east slopes of the Cascades should see increasing sunshine.
Thursday night and Friday, the high pressure builds further into the region with upper-level flow turning increasingly northwesterly. Although temperatures above Cascade Crest level continue to warm throughout the time period, lower-level temperatures will warm more slowly. Even so, freezing levels should reach 4000-5000 ft on Friday. Low-level westerly flow continues to keep low clouds banked against the west slopes of the Cascades, but expect low cloud decks to be thinner and with more frequent sun breaks. The east slopes of the Cascades, Olympics, and Mt. Rainier area should be mostly sunny.
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 cloudy with a chance of very light snow showers in the morning, then mostly clearing skies in the afternoon.
Thursday
Night
Mostly clear with low clouds and fog developing.
Thursday
Mostly cloudy.
Thursday
Night
Low clouds and fog.
Thursday
Mostly cloudy with decreasing chances of light snow showers.
Thursday
Night
Mostly cloudy with low clouds and fog.
Thursday
Mostly cloudy with decreasing chances of light snow showers.
Thursday
Night
Low clouds with clearing skies above.
Thursday
Mostly cloudy with decreasing chances of very light snow showers. Light W wind at the Pass.
Thursday
Night
Mostly cloudy with low clouds. Light W wind at the Pass.
Thursday
Mostly cloudy with decreasing chances of very light snow showers. Light W wind at the Pass.
Thursday
Night
Mostly cloudy with low clouds. Light W wind at the Pass.
Thursday
Partly cloudy with a chance of very light snow showers.
Thursday
Night
Partly cloudy near the Cascade Crest with mostly clear skies to the east.
Thursday
Partly to mostly cloudy near the Cascade Crest with a chance of snow showers. Mostly sunny further east.
Thursday
Night
Partly cloudy near the Cascade Crest with mostly clear skies to the east.
Thursday
Partly to mostly cloudy near the Cascade Crest with a chance of snow showers. Mostly sunny further east.
Thursday
Night
Mostly clear.
Thursday
Decreasing light snow showers. Strong ridgeline winds becoming moderate by late morning.
Thursday
Night
Low clouds banked against the west slopes of Mt Hood, with clear skies further east.
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).