We're in store for another beautiful day. Temperatures are crisp, but have gradually warmed to the teens and 20's on the west side of the crest, while they remain near or below 0 on the east side. An inversion should become more established today as warmer air above the cold pool continues to warm. The temperature and pressure gradient between the east side and west side of the Cascades is driving moderate and gusty easterly winds through gaps and passes. This is occurring mainly from Stevens Pass south to Hood. These winds should peak in the morning, but will remain through the day. High clouds begin to stream in from the north, first affecting the northern zones by noon, then begin to create filtered sunshine for the southern areas late in the day.
On Tuesday, expect a classic pre-frontal day with high and mid level clouds filling in from the SW. Temperatures will continue to warm up gradually above the inversion, but the very cold arctic air continues to push up against the east side of the Cascades. Snow may begin to fall in the southwest and Hood by the late afternoon, but should hold off til evening for the rest of our region.
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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Monday
Clear with increasing high clouds by mid day creating filtered sunshine.
Monday
Night
High thin clouds and cool.
Monday
Clear with increasing high clouds by mid day creating filtered sunshine.
Monday
Night
High clouds and cool.
Monday
Clear with increasing high clouds by mid day creating filtered sunshine.
Monday
Night
High, thin clouds and cool.
Monday
Mostly clear and cold with filtered sunshine later. East winds peaking this morning through gaps near the Cascade crest.
Monday
Night
High, thin clouds and cool.
Monday
Clear with increasing high clouds by mid day creating filtered sunshine. East winds through the pass peak in the morning, and taper off later. Light ridgeline winds above the inversion.
Monday
Night
Thin, high clouds and cold with light winds through the pass and at ridgelines.
Monday
Mostly clear and cold with filtered sunshine later. East winds at pass and ridgeline peak in the moderate to strong range in the morning, but continue during the day.
Monday
Night
Thin, high clouds with light east winds through the pass and at ridgetop.
Monday
Clear with increasing high clouds by mid day creating filtered sunshine.
Monday
Night
Thin, high clouds and cold.
Monday
Clear and cold with increasing high clouds by mid day creating filtered sunshine. East winds below 5,000ft peak in moderate range in the morning.
Monday
Night
Mostly clear with some high clouds, and cold.
Monday
Clear and cold with increasing high clouds later creating filtered sunshine.
Monday
Night
Mostly clear and cold.
Monday
Strong inversion. Clear with filtered sunshine by late in the day.
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).