Keep your sunglasses handy with high pressure in control of the weather for the next several days. Mid-mountain temperatures will be a bit cooler than the last 2 days, with high temperatures "only" in the 40s vs the 50s. After a weak weather feature moved through last night, drier air is moving in at mid and upper elevations today, keeping low clouds and the temperature inversions shallow and confined to lower slopes/deep valleys.
As easterly offshore begins to increase today, and ramps up further overnight, we may start to see some low clouds mired along the east slopes of the Cascades get sucked towards the major Cascade Passes. These low clouds will likely have a harder time making it to the higher Passes; Washington, Stevens and White, but should have an easier time squeezing through Snoqualmie Pass. Once it sets in, there's not much change in the pressure pattern through Saturday morning. Easterly Pass level winds will be breezy, and those easterlies may extend up to ridgelines.
Mid-mountain temperatures will start to climb for the Olympics and the west slopes of the Cascades further west of the crest on Friday, and in these areas, we're likely to see mid-mountain temperatures push back near or above 50F. Freezing levels will remain high, in the 11,000-13,000' range generally, highest down near Mt Hood.
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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Thursday
Mostly sunny. Areas of valley low clouds. Light ridgeline winds.
Thursday
Night
Mostly clear. Areas of valley low clouds. Light to occasionally moderate ridgeline winds.
Thursday
Mostly sunny. Areas of valley low clouds. Light ridgeline winds.
Thursday
Night
Mostly clear. Areas of valley low clouds. Light to occasionally moderate ridgeline winds.
Thursday
Mostly sunny. Areas of valley low clouds. Light to occasionally moderate ridgeline winds.
Thursday
Night
Mostly clear. Areas of valley low clouds. Light to occasionally moderate ridgeline winds.
Thursday
Mostly sunny. Areas of valley low clouds. Light to occasionally moderate ridgeline winds.
Thursday
Night
Mostly clear. Areas of valley low clouds. Light to occasionally moderate ridgeline winds.
Thursday
Mostly sunny. Patchy fog and low clouds near the Pass. Light to moderate N-NW winds at ridgeline. Light E winds at Pass level.
Thursday
Night
Mostly clear. Areas of low clouds and fog, near and east of the Pass. Moderate E winds at Pass level, light to moderate ESE at ridgeline.
Thursday
Mostly sunny. Patchy fog and low clouds near the Pass. Light to moderate N-NW winds at ridgeline. Light E winds at Pass level.
Thursday
Night
Mostly clear. Areas of low clouds and fog, near and east of the Pass. Moderate E winds at Pass level, light to moderate ESE at ridgeline.
Thursday
Mostly sunny. Areas of valley low clouds. Light to occasionally moderate ridgeline winds.
Thursday
Night
Mostly clear. Areas of valley low clouds. Light to occasionally moderate ridgeline winds.
Thursday
Mostly sunny. Areas of valley low clouds. Light to occasionally moderate ridgeline winds.
Thursday
Night
Mostly clear. Areas of valley low clouds. Light to occasionally moderate ridgeline winds.
Thursday
Mostly sunny. Areas of valley low clouds. Light to occasionally moderate ridgeline winds.
Thursday
Night
Mostly clear. Areas of valley low clouds. Light to occasionally moderate ridgeline winds.
Thursday
Mostly sunny. Areas of low clouds. Light to occasionally moderate ridgeline winds.
Thursday
Night
Mostly clear. Areas of low clouds. 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).