Friday will be the last fully dry day this week. A swath of moderate NNE winds Thursday night continues to taper toward the light rain. The upper-level high pressure centered offshore has brought milder temperatures to mid and upper elevations west of the Cascade Crest while temperatures remain chilly east of the Cascades, through the mountain gaps, and in deeper valleys. Freezing levels will rise to 7500-9000 ft by Friday afternoon for the Olympics, Mt. Baker, and Mt. Rainier areas. High and mid-level clouds should partially block full sunshine at times.
The offshore high gradually shifts westward, allowing for NW wind to develop ahead of a trough moving southward down the Canadian Rockies and pass-level winds should shift westerly overnight. Saturday should be a transitional day with increasing clouds and moderate WNW winds developing that will be the strongest east of the Cascades. Some light snowfall could develop anywhere from around Snoqualmie Pass northward. Significant snow accumulations are not expected.
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
Mostly sunny with mid-level clouds at times.
Friday
Night
Mostly clear with increasing mid and high-level clouds overnight.
Friday
Mostly sunny with mid-level clouds at times.
Friday
Night
Mostly clear with increasing mid and high-level clouds overnight.
Friday
Mostly sunny with mid-level clouds at times.
Friday
Night
Mostly clear with increasing mid and high-level clouds overnight.
Friday
Mostly sunny with mid-level clouds at times.
Friday
Night
Mostly clear with increasing mid and high-level clouds overnight.
Friday
Mostly sunny with mid-level clouds at times. Light ridgeline and E wind at the Pass.
Friday
Night
Mostly clear with increasing mid and high-level clouds overnight. Light ridgeline and variable wind at the Pass.
Friday
Mostly sunny with mid-level clouds at times. Light ridgeline and light to occasionally moderate E wind at the Pass becoming light.
Friday
Night
Mostly clear with increasing mid and high-level clouds overnight. Light ridgeline and variable wind at the Pass.
Friday
Mostly sunny with mid-level clouds at times.
Friday
Night
Mostly clear with increasing mid and high-level clouds overnight.
Friday
Mostly sunny with mid-level clouds at times.
Friday
Night
Mostly clear with increasing mid and high-level clouds overnight.
Friday
Mostly sunny with mid-level clouds at times.
Friday
Night
Mostly clear with increasing mid and high-level clouds overnight.
Friday
Mostly sunny with mid-level clouds at times.
Friday
Night
Mostly clear with increasing mid and high-level clouds overnight.
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).