Westerly flow continues to bring a few light showers to the west slopes of the Cascades and Mt. Hood behind a passing disturbance. Moderate ridgeline winds linger along the east slopes of the Cascades and Mt Hood on Thursday but should decrease throughout the day after peaking in the early morning hours. A weak shortwave ridge brings a gradual drying and warming trend, with snow levels rising from 3500-4000 ft in the morning to 4000-5000 ft in the afternoon. Temperatures will increase with the down-slope drying air along the east slopes of the Cascades.
Thursday night, the weak ridge dries out southern parts of the forecast region with scattered to isolated showers continuing further north as light winds turn SSWerly and temperatures continue to rise gradually.
A broad closed low off the California/Oregon coast gradually drifts NE on Friday, extending a frontal band of light rain/snow into southwest parts of our forecast region on Friday. It's unclear how far this will progress during the day. Snow levels should be above seasonal norms in the 5000-6500 ft range.
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
Partly cloudy with a chance of rain or snow showers in the afternoon.
Thursday
Night
Cloudy.
Thursday
Mostly cloudy with a few very light rain or snow showers.
Thursday
Night
Mostly cloudy in the evening, then becoming cloudy with scattered light rain and snow showers overnight.
Thursday
Mostly cloudy with decreasing light rain or snow showers.
Thursday
Night
Cloudy with increasing light rain and snow showers.
Thursday
Mostly cloudy with scattered light rain or snow showers.
Thursday
Night
Cloudy with decreasing light rain and snow showers.
Thursday
Mostly cloudy with decreasing light rain or snow showers. Light to occasionally moderate ridgeline and light W wind at the Pass.
Thursday
Night
Cloudy with scattered light rain and snow showers. Light ridgeline and W wind at the Pass becomes variable or E overnight.
Thursday
Mostly cloudy with decreasing light rain or snow showers. Light to moderate ridgeline and light W wind at the Pass.
Thursday
Night
Cloudy with scattered light rain and snow showers. Light ridgeline and W wind at the Pass becomes variable or E overnight.
Thursday
Partly cloudy with a slight chance of a sprinkle or snow flurry near the Cascade Crest.
Thursday
Night
Partly cloudy with a few light rain or snow showers overnight.
Thursday
Partly cloudy with a chance of light rain or snow showers near the Cascade Crest. Moderate ridgeline winds.
Thursday
Night
Partly cloudy with a few light rain or snow showers.
Thursday
Partly cloudy with a chance of light rain or snow showers near the Cascade Crest.
Thursday
Night
Partly cloudy with a chance of snow flurries or sprinkles near the Cascade Crest.
Thursday
Mostly cloudy with a chance of light rain or snow showers. Moderate to occasionally strong ridgeline winds gradually decrease.
Thursday
Night
Mostly cloudy with a chance of light rain or snow showers in the evening.
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).