Today will be marked by weak and ill-defined weather features. A weak warm front will drift north today, bringing some light showers to the south and central WA Cascades. Another upper level feature will bring light showers into the Olympics and northwest Cascades, neither will amount to much in terms of snowfall accumulation. Things will be more interesting down near the Columbia River Gorge and Mt Hood near the storm track. After some showers, and/or freezing fog at Mt Hood this morning, light snow will develop as the next warm frontal wave pushes over Oregon this afternoon. Strong ridgeline winds will continue in this area as well.
This warm frontal boundary will stay in place through this evening, until a low pressure system located offshore, begins to lift northward, dragging light to moderate warm frontal precipitation over the area overnight and through Friday. Offshore flow will crank up, driving strong east winds through the Passes, strong SE ridgeline winds tonight through tomorrow morning, and helping to keep snow levels low. The caveat will be the Mt Hood area, where freezing rain is possible from late Thursday night through Friday morning. That freezing rain threat will extend to Snoqualmie and White Passes later Friday, although the chances are lower for these locations. For areas further west of the Cascade crest, look for a slow warming trend tonight through Friday, with rain starting to push into the 3000-4000' range and even higher over the Olympics.
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
Cloudy with a scattered of light rain and snow showers. Light to moderate ridgeline winds.
Thursday
Night
Cloudy with a chance of light snow late. Light to moderate ridgeline winds.
Thursday
Cloudy with a scattered of light rain and snow showers. Light to moderate ridgeline winds.
Thursday
Night
Cloudy with a chance of light snow late. Light to moderate ridgeline winds.
Thursday
Cloudy with a scattered of light rain and snow showers. Light to occasionally moderate ridgeline winds.
Thursday
Night
Cloudy with a chance of light snow late. Light to moderate ridgeline winds.
Thursday
Cloudy with periods of light rain and snow. Light to moderate ridgeline winds.
Thursday
Night
Light snow becoming light to occasionally moderate overnight. Ridgeline winds increasing and becoming moderate to strong.
Thursday
Cloudy with a scattered of light snow showers. Light to occasionally moderate E level Pass winds and S ridgeline winds.
Thursday
Night
Cloudy with light snow developing after midnight. Moderate E level Pass winds and SE ridgeline winds.
Thursday
Cloudy with a scattered of light rain and snow showers. Light to occasionally moderate ridgeline winds.
Thursday
Night
Cloudy with light snow developing in the evening. Moderate to strong E level Pass winds and SE ridgeline winds.
Thursday
Cloudy.
Thursday
Night
Thursday
Cloudy with a chance of snow showers, mainly this morning.
Thursday
Night
Light snow becoming light to occasionally moderate overnight. Ridgeline winds increasing and becoming moderate.
Thursday
Cloudy with periods of light snow.
Thursday
Night
Light snow becoming light to occasionally moderate overnight. Ridgeline winds increasing and becoming moderate.
Thursday
Cloudy with light rain and snow showers, and freezing fog mid mountain in the morning. Light snow becoming moderate in the afternoon. Strong ridgeline winds.
Thursday
Night
Light to moderate rain and snow, with a chance of freezing rain lower/mid mountain after midnight. Strong 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).