We're on the southern edge of an upper low that passed inland through British Columbia last night. On the backside of the trough, we are finally seeing some cooler, although far from cold, temperatures this morning. Sub-freezing temperatures are confined to mid-elevations and higher for central and northern zones. Further south, temperatures have cooled, but freezing levels are still sitting in the 7000-9000' range. High temperature this afternoon will be 10-20F colder than Monday.
Strong west winds ramped up overnight with the trough's inland passage, particularly in central and southern areas. These elevated westerly winds will continue through the morning, but will begin to ease off by mid-day.
Low clouds worked inland overnight and can be found along the west slopes of the Cascades and towards the Passes. The low-level moisture is shallow with clear skies generally above 5000'. Low clouds will break up this afternoon, and we can expect mostly sunny skies for all areas.
For Tuesday night, expect mostly clear skies. We'll see freezing levels and temperatures climb several degrees on Wednesday under mostly sunny skies.
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 except for areas of low clouds below 5000' this morning. Light to occasionally moderate ridgeline winds.
Tuesday
Night
Mostly clear. Light ridgeline winds.
Tuesday
Partly sunny to mostly cloudy with low clouds below 5000' this morning. Mostly sunny mid-day onward. Light to occasionally moderate ridgeline winds.
Tuesday
Night
Mostly clear. Light ridgeline winds.
Tuesday
Mostly cloudy with low clouds below 5000' this morning. Mostly sunny mid-day onward. Light to moderate ridgeline winds.
Tuesday
Night
Mostly clear. Light to occasionally moderate ridgeline winds.
Tuesday
Mostly sunny except for areas of low clouds below 5000' this morning. Moderate to strong ridgeline winds this morning, easing in the afternoon.
Tuesday
Night
Mostly clear. Light to moderate ridgeline winds.
Tuesday
Mostly sunny except for areas of low clouds near and west of the Pass below 5000' this morning. Moderate W Pass level and ridgeline winds this morning, easing in the afternoon.
Tuesday
Night
Mostly clear. Light to occasionally moderate W ridgeline and Pass level winds.
Tuesday
Mostly sunny except for areas of low clouds near and west of the Pass below 5000' this morning. Moderate to occasionally strong W winds at Pass level and ridgeline this morning, easing in the afternoon.
Tuesday
Night
Mostly clear. Light to occasionally moderate W ridgeline and Pass level winds.
Tuesday
Mostly sunny except for areas of low clouds near the and west of the crest this morning. Moderate ridgeline winds this morning, easing in the afternoon.
Tuesday
Night
Mostly clear. Light to occasionally moderate ridgeline winds.
Tuesday
Mostly sunny except for areas of low clouds near the crest this morning. Moderate to strong ridgeline winds this morning, slowly easing in the afternoon.
Tuesday
Night
Mostly clear. Light to moderate ridgeline winds.
Tuesday
Mostly sunny. Moderate to strong ridgeline winds this morning, slowly easing in the afternoon.
Tuesday
Night
Mostly clear. Light to occasionally moderate ridgeline winds.
Tuesday
Mostly sunny. Areas of low clouds west side of the mountain. Moderate to strong ridgeline winds this morning, slowly easing in the afternoon.
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).