Happy New Year from NWAC! We'll start 2024 on a quiet note as a ridge of high pressure builds over the area today. Low clouds along the east slopes of the Cascades may play peak-a-boo with the Cascade Passes thanks to easterly flow. Clouds should stay below 4500', so if they do roll in, there's a better chance that upper slopes will stay in the sun. There will be a moderate SE breeze near Snoqualmie Pass with lighter winds but noticeable winds elsewhere. While cooler freezing levels will prevail along the east side of the Cascades, we'll see freezing levels rise to 4500-6000' for the west slopes of the Cascades, Olympics and Mt Hood area. Mostly sunny skies will give way to some filtered sunshine late in the day as a frontal system edges closer to our coast.
A familiar pattern returns with a weakening frontal system oriented north to south moving towards the area on Tuesday. We should see increasing offshore flow and resulting E-SE winds in many locations. Clouds should lower Tuesday afternoon and many areas may see light precipitation before sunset.
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
Mostly sunny becoming partly sunny with increasing high clouds in the afternoon.
Monday
Night
Partly cloudy in the evening, then cloudy.
Monday
Mostly sunny. Increasing high clouds in the afternoon. Periods of moderate ridgeline winds.
Monday
Night
Partly cloudy in the evening, then cloudy. Moderate ridgeline winds.
Monday
Mostly sunny. Increasing high clouds in the afternoon.
Monday
Night
Partly cloudy in the evening, then cloudy.
Monday
Mostly sunny. Increasing high clouds in the afternoon. Areas of low clouds near and east of White Pass. Periods of moderate ridgeline winds.
Monday
Night
Partly cloudy in the evening, then cloudy. Moderate ridgeline winds.
Monday
Mostly sunny upper slopes. Areas of low clouds lower slopes near and east of the Pass. Light to moderate E ridgeline and Pass level winds.
Monday
Night
Partly cloudy in the evening, then cloudy.Moderate SE ridgeline and E Pass level winds.
Monday
Mostly sunny upper slopes. Areas of low clouds lower slopes near and east of the Pass. Moderate E ridgeline and Pass level winds.
Monday
Night
Partly cloudy in the evening, then cloudy. Moderate to occasionally strong SE ridgeline and E Pass level winds.
Monday
Mostly sunny upper slopes, cloudy lower slopes. Increasing high clouds in the afternoon.
Monday
Night
Partly cloudy in the evening, then cloudy.
Monday
Mostly sunny upper slopes, cloudy lower slopes. Increasing high clouds in the afternoon.
Monday
Night
Partly cloudy in the evening, then cloudy. Moderate ridgeline winds.
Monday
Mostly sunny upper slopes, cloudy lower slopes. Increasing high clouds in the afternoon.
Monday
Night
Partly cloudy in the evening, then cloudy.
Monday
Mostly sunny. Increasing high clouds in the afternoon.
Monday
Night
Partly cloudy in the evening, then cloudy. 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).