After a wet and stormy 2nd half of December, we'll close out 2024 on a dry note today as an upper level ridge slides over the area. Mountain weather stations are reporting some of the coldest temperatures in some time, with many stations near or above 5000' in the teens this morning. Freezing levels will rebound to 3000-3500' this afternoon with partly sunny skies in the morning giving way to filtered sunshine and a high overcast later this afternoon. Cool easterly flow will drag low clouds along the east slope of the Cascades through Snoqualmie Pass, and along the eastern approaches for Stevens and White Passes. Ridgeline winds should tick up towards the 10-15mph range this afternoon as a frontal system approaches the coast.
A Pacific frontal system will undercut the ridge tonight and spread light precipitation into northern Oregon and up through much of Washington. This system will be unremarkable snow-wise, but snow levels will be quite low, with snow accumulating between 1000-2000' Tuesday night and Wednesday morning. We'll see light post-frontal showers on New Year's Day with some clearing mid-day and afternoon. High clouds from the next frontal system will be on our doorstep before sunset Wednesday.
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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Tuesday
Mostly sunny this morning, then partly sunny with filtered sunshine this afternoon. Light winds, becoming light to occasionally moderate in the afternoon.
Tuesday
Night
Cloudy with light snow developing in the evening. Light to moderate ridgeline winds.
Tuesday
Mostly sunny this morning, then partly sunny with filtered sunshine this afternoon. Light winds, becoming light to occasionally moderate in the afternoon.
Tuesday
Night
Cloudy. Chance of light snow after midnight. Light to occasionally moderate ridgeline winds.
Tuesday
Mostly sunny this morning, then partly sunny with filtered sunshine this afternoon. Light winds, becoming light to occasionally moderate in the afternoon.
Tuesday
Night
Cloudy with light snow developing in the evening. Light to occasionally moderate ridgeline winds.
Tuesday
Mostly sunny this morning, then partly sunny with filtered sunshine this afternoon. Light winds, becoming light to occasionally moderate in the afternoon.
Tuesday
Night
Cloudy with light snow developing in the evening. Light to moderate ridgeline winds.
Tuesday
Mostly sunny this morning, then partly sunny with filtered sunshine this afternoon. Areas of low clouds near and especially east of the Pass. Light east winds at Pass level, and light to occasionally moderate SE winds at ridgeline.
Tuesday
Night
Cloudy with light snow developing in the evening. Light to occasionally E-SE moderate ridgeline and Pass level winds.
Tuesday
Cloudy near and especially east of the Pass. Partly sunny upper slopes with increasing high clouds in the afternoon. Light east winds at Pass level, and light to occasionally moderate SE winds at ridgeline.
Tuesday
Night
Cloudy with light snow developing in the evening. Light to occasionally E-SE moderate ridgeline and Pass level winds.
Tuesday
Mostly sunny with areas of low clouds and valley fog this morning, becoming partly sunny with filtered sunshine this afternoon. Light winds, becoming light to occasionally moderate in the afternoon.
Tuesday
Night
Cloudy with a chance of light snow after midnight. Light to occasionally moderate ridgeline winds.
Tuesday
Mostly sunny with areas of low clouds and valley fog this morning, becoming partly sunny with filtered sunshine this afternoon. Light winds, becoming light to occasionally moderate in the afternoon.
Tuesday
Night
Cloudy with light snow developing in the evening. Light to occasionally moderate ridgeline winds.
Tuesday
Mostly sunny with areas of low clouds and valley fog this morning, becoming partly sunny with filtered sunshine this afternoon. Light winds, becoming light to occasionally moderate in the afternoon.
Tuesday
Night
Cloudy with light snow developing in the evening. Light to moderate ridgeline winds.
Tuesday
Mostly sunny this morning, then partly sunny with filtered sunshine this afternoon. Light winds, becoming light to occasionally moderate in the afternoon.
Tuesday
Night
Cloudy with light snow developing in the evening. 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).