Winter will make a comeback this weekend as a strong frontal system drops south carrying moisture and cold air from the Gulf of Alaska. A frontal boundary will spread precipitation over the north Cascades and Olympics this morning and spread southward through the Washington Cascades this afternoon. Westerly winds ahead of and behind the front will become strong in all areas, and extreme for areas east of the Cascades and down at Mt. Hood. Moderate snowfall in the Mt Baker area this afternoon will shift to the central Cascades late this afternoon and overnight as a strong Puget Sound Convergence Zone takes aim at the Mt. Loop and Stevens Pass area first, and then slides towards Snoqualmie Pass Sunday morning. Stevens Pass should see several hours of heavy snowfall tonight along with strong winds. Snow levels hover around 3000-3500' with onset of precipitation and until the frontal passage and Snoqualmie Pass may initially mix with rain at Pass level through early evening.
Snow showers will continue on Sunday, heaviest from the Snoqualmie Pass area and south to Mt. Hood in the morning. Snow showers will continue in the southwest Cascades and Mt. Hood area as showers become more scattered for other areas. Strong west winds will also drop off over Washington State Sunday but continue over the Mt. Hood area. Colder air will have settled over the region on Sunday as the upper trough digs over the PNW.
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
Cloudy with light rain and snow developing in the morning. Ridgeline winds becoming strong.
Saturday
Night
Light to occasionally snow showers. Moderate to strong ridgeline winds.
Saturday
Cloudy with light rain and snow developing in the morning and becoming moderate in the afternoon. Ridgeline winds becoming strong.
Saturday
Night
Moderate snow showers becoming lighter after midnight. Moderate to strong ridgeline winds decreasing overnight.
Saturday
Cloudy with light rain and snow developing in the morning and becoming light to moderate in the afternoon. Ridgeline winds becoming strong.
Saturday
Night
Moderate to locally heavy snow showers. Moderate to strong ridgeline winds
Saturday
Cloudy with light rain and snow developing in the afternoon. Ridgeline winds becoming strong.
Saturday
Night
Light to moderate rain and snow showers. Strong ridgeline winds.
Saturday
Cloudy with light rain and snow developing later this morning and increasing late in the afternoon. Ridgeline winds and Pass level W winds becoming strong.
Saturday
Night
Moderate to heavy snow showers. Strong ridgeline and Pass level W winds.
Saturday
Cloudy with light rain and snow developing mid-day and increasing late in the afternoon. Ridgeline winds and Pass level W winds becoming strong.
Saturday
Night
Moderate rain and snow showers becoming moderate to heavy after midnight. Strong ridgeline and Pass level W winds.
Saturday
Cloudy with light rain and snow developing late morning, heaviest near the Cascade crest. Strong ridgeline winds.
Saturday
Night
Light snow showers, occasionally moderate near the Cascade crest. Strong ridgeline winds decreasing overnight.
Saturday
Cloudy with light rain and snow developing mid-day, heaviest near the Cascade crest. Strong ridgeline winds becoming extreme in the afternoon.
Saturday
Night
Light snow showers, except mooderate near the Cascade crest. Strong to extreme ridgeline winds.
Saturday
Cloudy with light rain and snow developing near the Cascade crest in the afternoon. Strong ridgeline winds.
Saturday
Night
Light snow showers, occasionally moderate near the Cascade crest. Strong ridgeline winds.
Saturday
Cloudy. Chance of light rain and snow late. Strong to extreme ridgeline winds.
Saturday
Night
Light to moderate rain and snow showers increasing after midnight. Strong to extreme 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).