We're in for another sunny day across the forecast regions as a high pressure ridge remains firmly in control of our weather. Temperature inversions this morning in many of the mountain valleys and passes should make it quite chilly at the trailheads. However, warmer air has already begun to push into the area causing temperatures higher up the mountain to climb. With plenty of sunshine, calm winds, and warming temperatures it may feel more like spring than mid-January. The exception could be some of the valleys east of the Cascade Crest, where cold air will do its best to persist throughout the day. While you could see passing bands of high clouds, particularly in the northern zones, it should be a beautiful day in the mountains.
Mostly clear skies allow temperature inversions to reestablish overnight even as the upper air mass continues to warm. Freezing levels and 5000 ft temperatures don't paint a very clear picture of the reality on the ground. You could encounter multiple freezing levels, with cold air pooling into valleys, passes, and other low lying areas.
On Thursday a short wave disturbance will approach from the north. Look for increasing clouds and ridgeline winds later in the day. Temperatures quickly fall as the system returns much colder air to the region. Precipitation should hold off until the evening for whatever is left of this weak storm.
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
Mostly sunny with passing high clouds.
Wednesday
Night
Mostly clear with temperature inversions forming in mountain valleys and passes.
Wednesday
Mostly sunny with passing high clouds.
Wednesday
Night
Mostly clear with temperature inversions forming in mountain valleys and passes.
Wednesday
Mostly sunny with passing high clouds.
Wednesday
Night
Mostly clear with temperature inversions forming in mountain valleys and passes.
Wednesday
Mostly sunny with passing high clouds.
Wednesday
Night
Mostly clear with temperature inversions forming in mountain valleys and passes.
Wednesday
Mostly sunny with passing high clouds. Very light easterly flow at pass level.
Wednesday
Night
Mostly clear with temperature inversions forming in mountain valleys and passes. Light E flow at pass level.
Wednesday
Mostly sunny with passing high clouds. Very light easterly flow at pass level.
Wednesday
Night
Mostly clear with temperature inversions forming in mountain valleys and passes. Light E flow at pass level.
Wednesday
Mostly sunny with passing high clouds.
Wednesday
Night
Mostly clear with temperature inversions forming in mountain valleys and passes. Winds becoming W light to moderate.
Wednesday
Mostly sunny with passing high clouds.
Wednesday
Night
Mostly clear with temperature inversions forming in mountain valleys and passes. Winds becoming W light to moderate.
Wednesday
Mostly sunny with passing high clouds.
Wednesday
Night
Mostly clear with temperature inversions forming in mountain valleys and passes. Winds becoming NW light to moderate.
Wednesday
Mostly sunny with passing high clouds.
Wednesday
Night
Mostly clear with temperature inversions forming in mountain valleys and passes.
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).