It's another balmy start to a mid-winter's day with mountain temperatures in the 40s and even 50s this morning, and freezing levels between 11,000-13,000' across the region. Low stratus clouds are mired in the western Washington lowlands and banked up against the west slopes of the Cascades. Low clouds and fog are patchier near the Cascade Passes and along the east slopes of the Cascades valleys than on the west side. No matter which side you approach the mountains from, you'll need sunscreen and fewer layers than you would typically wear in mid-January.
A weak weather disturbance currently over Vancouver Island will not bring precipitation, but will push some high clouds the North Cascades and Olympics later this afternoon, along with a subtle cooling trend. W-NW winds will also kick up with this feature late this afternoon and overnight, with ridgeline winds rising into the moderate range. Freezing levels will dip ever so slightly tonight.
The upper level ridge will rebuild along the west coast on Thursday. Freezing levels will once again rebound to 11,000-12,000'. The biggest change for Thursday will be felt with mid-mountain temperatures that will trend a bit cooler, generally in the 40s vs 50s. Also, east winds will start to develop in the Passes Thursday afternoon as offshore flow begins to ramp up.
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 increasing high clouds in the afternoon. Areas of valley fog and low clouds. Light to moderate ridgeline winds, increasing in the afternoon.
Wednesday
Night
Partly to mostly clear. Areas of low clouds. Moderate ridgeline winds.
Wednesday
Mostly sunny with increasing high clouds in the afternoon. Areas of valley fog and low clouds. Light to moderate ridgeline winds, increasing in the afternoon.
Wednesday
Night
Partly to mostly clear. Areas of low clouds. Moderate ridgeline winds.
Wednesday
Mostly sunny with increasing high clouds in the afternoon. Areas of valley fog and low clouds. Light to moderate ridgeline winds, increasing in the afternoon.
Wednesday
Night
Partly to mostly clear. Areas of low clouds. Moderate ridgeline winds.
Wednesday
Mostly sunny with increasing high clouds in the afternoon. Areas of valley fog and low clouds. Light to moderate ridgeline winds, increasing in the afternoon.
Wednesday
Night
Partly to mostly clear. Areas of low clouds. Moderate ridgeline winds.
Wednesday
Mostly sunny with increasing high clouds in the afternoon. Areas of valley fog near the Pass. Light to moderate W ridgeline winds, increasing in the afternoon. Light E winds at Pass level becoming W in the afternoon.
Wednesday
Night
Partly to mostly clear. Areas of low clouds near the Pass. Moderate W ridgeline and Pass level winds.
Wednesday
Mostly sunny. Areas of valley fog near the Pass. Light to moderate W ridgeline winds, increasing in the afternoon. Light E winds at Pass level becoming W in the afternoon.
Wednesday
Night
Partly to mostly clear. Areas of low clouds near the Pass. Moderate W ridgeline and Pass level winds.
Wednesday
Mostly sunny with increasing high clouds in the afternoon. Areas of valley fog. Moderate ridgeline winds, increasing in the afternoon.
Wednesday
Night
Partly to mostly clear. Moderate ridgeline winds.
Wednesday
Mostly sunny. Areas of valley fog. Moderate ridgeline winds, increasing in the afternoon.
Wednesday
Night
Partly to mostly clear. Moderate ridgeline winds.
Wednesday
Mostly sunny. Areas of valley fog. Light to moderate ridgeline winds, increasing in the afternoon.
Wednesday
Night
Mostly clear. Moderate ridgeline winds.
Wednesday
Mostly sunny. Light to occasionally 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).