A weak frontal system along the coast will struggle to push inland this morning, with showers affecting only the Olympics and western portions of the north Cascades through mid-day and clouds elsewhere. A new low pressure system developing along the quasi-stationary frontal boundary will invigorate precipitation, spreading widespread precipitation inland this evening. For today, cooler snow levels are shown for the Olympics and Mt. Baker area, while slightly milder freezing levels are shown for other zones, where only light precipitation is expected through 4pm.
Steady rain and snow will turn to showers after midnight, with the showers continuing longest for the Cascades of Skagit and Whatcom counties through Saturday morning, with more isolated snow showers elsewhere. The Mt Baker area and southward to the Mt Loop Highway will likely pick up the most snow, 4-9", through Saturday morning.
An elongated upper level trough from British Columbia to off the Oregon Coast will keep SW flow aloft over the area on Saturday. A new warm front will keep clouds over most of the area on Saturday, with some light snow moving into Mt Hood and perhaps the south WA Cascades during the afternoon, producing a quick 1-2" of new snow before sundown.
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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Friday
Cloudy with periods of light snow, becoming steadier in the afternoon. Moderate ridgeline winds.
Friday
Night
Light to occasionally moderate snow becoming showers after midnight. Moderate ridgeline winds.
Friday
Cloudy with periods of light snow, becoming light to moderate in the afternoon. Moderate ridgeline winds.
Friday
Night
Light to moderate snow becoming showers after midnight. Moderate ridgeline winds.
Friday
Cloudy in the morning with light rain and snow developing mid to late afternoon. Light to moderate ridgeline winds.
Friday
Night
Light to moderate snow becoming showers after midnight. Moderate ridgeline winds.
Friday
Partly to mostly cloudy in the morning with light rain and snow developing mid to late afternoon. Light to moderate ridgeline winds.
Friday
Night
Light to occasionally moderate snow becoming showers after midnight. Moderate ridgeline winds.
Friday
Partly to mostly cloudy in the morning with light rain and snow developing mid to late afternoon. Light to moderate SW ridgeline winds. Variable winds at Pass level.
Friday
Night
Light to occasionally moderate snow becoming showers after midnight. Moderate SW ridgeline winds. Light to moderate W winds at Pass level.
Friday
Partly to mostly cloudy in the morning with light rain and snow developing mid to late afternoon. Light to moderate SW ridgeline winds. Variable winds at Pass level.
Friday
Night
Light to occasionally moderate snow becoming showers after midnight. Moderate ridgeline winds. Moderate SW ridgeline winds. Light to moderate W winds at Pass level.
Friday
Cloudy in the morning with a chance of light snow developing late afternoon. Light to moderate ridgeline winds.
Friday
Night
Light to occasionally moderate snow becoming scattered showers after midnight. Light to moderate ridgeline winds.
Friday
Partly to mostly cloudy in the morning with a chance of light snow developing late afternoon. Light to moderate ridgeline winds.
Friday
Night
Light to occasionally moderate snow becoming scattered showers after midnight. Moderate ridgeline winds.
Friday
Partly cloudy in the morning with a chance of light snow developing late afternoon. Light to moderate ridgeline winds.
Friday
Night
Light to occasionally moderate snow becoming scattered showers after midnight. Moderate ridgeline winds.
Friday
Partly cloudy in the morning with a chance of light snow developing late afternoon. Moderate ridgeline winds.
Friday
Night
Light to occasionally moderate snow becoming scattered showers after midnight. 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).