On Friday, another cold system approaches our region on NW flow. Clouds have moved into the northern third of Washington State and should thicken throughout the morning hours. Light snow follows suit, developing during the afternoon in the Olympics and Mt. Baker areas. The Mountain Loop and Washington Pass areas might get some light snow by the end of the day. From Stevens Pass southward, most areas will experience increasing high clouds, but mostly sunny and milder conditions. SSW ridgeline winds have already ramped up into the moderate in the Mt. Baker area and Washington Pass. Winds should gradually increase across northern Washington as the front approaches.
The cold front crosses the region from NW to SE Friday night, bringing moderate to strong W and WSW winds, moderate snow, and cooling temperatures. Snow levels start near Snoqualmie Pass level but should be well below pass level by Saturday morning.
Post-frontal snow showers and convergence should gradually decrease on Saturday with increasing sun breaks likely during the afternoon. With cold temperatures throughout the storm, expect high snow rations and snow totals of 6-12" for Mt. Baker, Stevens Pass, Snoqualmie Pass, Paradise, and possibly Mt. Hood.
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
Clouds lowering and thickening in the morning with light snow developing in the afternoon.
Friday
Night
Light snow.
Friday
Clouds lowering and thickening in the morning with light snow developing in the afternoon.
Friday
Night
Moderate snow, heaviest during the evening hours.
Friday
Clouds lowering and thickening from north to south, then light rain and snow developing late in the day.
Friday
Night
Increasing moderate snow in the evening, possibly heavy at times after midnight. Moderate to strong ridgeline winds.
Friday
Mostly sunny with high clouds increasing throughout the day.
Friday
Night
Snow developing during the evening; snow becoming moderate at Paradise and light at Crystal and White Pass.
Friday
Filtered sunshine with clouds lowering and thickening late in the day. Increasing light W winds at the Pass.
Friday
Night
Increasing light to moderate snow. Light to moderate W winds at the Pass.
Friday
Filtered sunshine with clouds lowering and thickening late in the day. Increasing light W winds at the Pass.
Friday
Night
Increasing light to moderate snow. Moderate to strong ridgeline winds. Moderate W winds at the Pass.
Friday
Partly cloudy with increasing clouds and a chance of light snow late in the day.
Friday
Night
Decreasing light snow. Moderate to strong ridgeline winds.
Friday
Filtered sunshine with high clouds lowering late in the day.
Friday
Night
Increasing light snow. Moderate to strong ridgeline winds.
Friday
Mostly sunny with high clouds increasing later in the day.
Friday
Night
Increasing light snow. Moderate to strong ridgeline winds.
Friday
Mostly sunny with high clouds increasing later in the day.
Friday
Night
Increasing light to moderate snow from late evening onward. Moderate to 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).