A low pressure system will track along the coast-line this morning and over the northern Inland waters of western WA this afternoon. The low pressure is unlikley to be as deep or powerful as previous forecasts suggested, so while mountain winds will still be strong in many areas today, they won't be as strong as forecast yesterday. Moderate to strong E-SE winds this morning will become S-SW mid to late afternoon. A warm front has brought rising snow levels near and west of the Cascade crest this morning, and snow levels should peak at 5000-5500' mid-day to early this afternoon for the entirety of the WA Cascades, before falling back to 4500' with the wind shift later this afternoon.
More moderate precipitation, locally heavy in the Mt Baker area this afternoon, should stretch across the north Cascades as a warm frontal boundary stalls out. Precipitation will become lighter generally south, outside scattered afternoon showers mainly affecting the SW Cascades and Mt Hood.
Showers will quickly fade this evening, and winds will ease. On Christmas Day, we'll see a similar but weaker upper-level disturbance pass from south to north over the area, and another round of moderate E-SE winds and generally light precipitation. Snow levels will be in the 3500-5000' 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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Wednesday
Moderate to occasionally heavy rain and snow. Moderate to strong ridgeline winds.
Wednesday
Night
Mostly cloudy, chance of showers in the evening. Light to moderate ridgeline winds.
Wednesday
Light to moderate rain and snow increasing in the afternoon and becoming occasionally heavy. Moderate ridgeline winds becoming strong in the afternoon.
Wednesday
Night
Mostly cloudy, chance of showers in the evening. Light to moderate ridgeline winds.
Wednesday
Light to moderate rain and snow increasing in the afternoon. Moderate to strong ridgeline winds.
Wednesday
Night
Mostly cloudy, chance of showers in the evening. Light to moderate ridgeline winds.
Wednesday
Light to occasionally moderate rain and snow becoming scattered light to moderate showers in the afternoon. Strong to locally extreme ridgeline winds.
Wednesday
Night
Mostly cloudy, chance of showers in the evening. Light to moderate ridgeline winds.
Wednesday
Periods of light to moderate rain and snow becoming light showers late. Moderate to strong E winds at Pass level, and SE winds at ridgeline. Winds becoming westerly late.
Wednesday
Night
Mostly cloudy, chance of showers in the evening. Light to moderate W Pass level and ridgeline winds.
Wednesday
Periods of light to moderate rain and snow becoming light showers late. Moderate to strong E winds at Pass level, and SE winds at ridgeline. Winds becoming westerly late.
Wednesday
Night
Mostly cloudy, chance of showers in the evening. Light to moderate W Pass level and ridgeline winds.
Wednesday
Light to moderate rain and snow. Moderate to strong ridgeline winds.
Wednesday
Night
Mostly cloudy, chance of showers in the evening. Light to moderate ridgeline winds.
Wednesday
Light to moderate rain and snow, becoming lighter showers in the afternoon. Moderate to strong ridgeline winds.
Wednesday
Night
Mostly cloudy, chance of showers in the evening. Light to moderate ridgeline winds.
Wednesday
Light to moderate rain and snow, becoming lighter showers in the afternoon. Moderate to strong ridgeline winds.
Wednesday
Night
Mostly cloudy, chance of showers in the evening. Light to moderate ridgeline winds.
Wednesday
Periods of light rain and snow, becoming light to moderate scattered showers in the afternoon. Moderate to strong ridgeline winds.
Wednesday
Night
Mostly cloudy, chance of showers in the evening. 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).