We're in for another day of benign weather with a strong upper level ridge over the western US keeping us dry and the storm track directed well north into British Columbia. Once again, expect sunny and mild conditions for mid and upper elevations with daytime mid-mountain high temperatures running in the 40s to even a few 50s today. If you're mired in the low clouds/valley fog, expect these conditions to persist with low December sun angles and nothing to stir up the lower atmosphere. The stratus is thicker and more extensive on the east side of the Cascades with cloud tops likely around 4000-4500'. Above the inversion and clouds, besides unseasonably mild temperatures, it's quite dry making for a stark transition from clouds to sunshine. Low level easterly flow will continue to draw low clouds/fog up to and in some cases through the Cascade Passes. Snoqualmie Pass will likely see low clouds come and go today while the low clouds should stay just east of Stevens and White Pass.
We can expect this pattern along with the 10,000-11,000 freezing levels to continue through Wednesday. A frontal system approaching on Thursday looks weak and won't likely bring much if any precipitation to the area, nor much cooler temperatures, but should increase cloud cover.
Weather Forecast
Olympics
West North
West Central
West South
Stevens Pass
Snoqualmie Pass
East North
East Central
East South
Mt. Hood
Use dropdown to select your zone
Tuesday
Mostly sunny. Areas of valley fog. Light to occasionally moderate ridgeline winds.
Tuesday
Night
Mostly clear. Areas of valley fog. Light to occasionally moderate ridgeline winds.
Tuesday
Mostly sunny. Areas of valley fog. Light to occasionally moderate ridgeline winds.
Tuesday
Night
Mostly clear. Areas of valley fog. Light to occasionally moderate ridgeline winds.
Tuesday
Mostly sunny. Areas of valley fog. Light to occasionally moderate ridgeline winds.
Tuesday
Night
Mostly clear. Areas of valley fog. Light to occasionally moderate ridgeline winds.
Tuesday
Mostly sunny. Areas of valley fog, especially near and east of White Pass. Light to occasionally moderate ridgeline winds.
Tuesday
Night
Mostly clear. Areas of valley fog, especially near and east of White Pass. Light to occasionally moderate ridgeline winds.
Tuesday
Mostly clear mid and upper slopes. Areas of fog and low clouds, near and especially east of the Pass. Light to moderate E winds at Pass level and WSW ridgeline winds.
Tuesday
Night
Mostly sunny mid and upper slopes. Areas of fog and low clouds, near and especially east of the Pass. Light to moderate E winds at Pass level and WSW ridgeline winds.
Tuesday
Mostly sunny mid and upper slopes. Areas of fog and low clouds, near and especially east of the Pass. Moderate E winds at Pass level and light to moderate WSW ridgeline winds.
Tuesday
Night
Mostly clear mid and upper slopes. Areas of fog and low clouds, near and especially east of the Pass. Moderate E winds at Pass level and light to moderate WSW ridgeline winds.
Tuesday
Mostly sunny mid and upper slopes. Cloudy, colder, with low clouds and fog lower slopes and valleys. Light to occasionally moderate ridgeline winds.
Tuesday
Night
Mostly clear mid and upper slopes. Cloudy, colder, with low clouds and fog lower slopes and valleys. Light to occasionally moderate ridgeline winds.
Tuesday
Mostly sunny mid and upper slopes. Cloudy, colder, with low clouds and fog lower slopes and valleys. Light to moderate ridgeline winds.
Tuesday
Night
Mostly clear mid and upper slopes. Cloudy, colder, with low clouds and fog lower slopes and valleys. Light to moderate ridgeline winds.
Tuesday
Mostly sunny mid and upper slopes. Cloudy, colder, with low clouds and fog lower slopes and valleys. Light to occasionally moderate ridgeline winds.
Tuesday
Night
Mostly clear mid and upper slopes. Cloudy, colder, with low clouds and fog lower slopes and valleys. Light to occasionally moderate ridgeline winds.
Tuesday
Mostly sunny. Areas of low clouds and valley fog, especially east side of the mountain.
Tuesday
Night
Mostly clear. Areas of low clouds and valley fog, especially east side of the mountain.
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).