Our little disturbance from last night is quickly exiting the region this morning. It left several locations with a small dusting of snow. While most areas will begin the day with clouds and gusty winds, the overall trend will be for drying and clearing. Today's mostly sunny weather will be a bit different from the other days this week. Onshore westerly flow will prevent the inversions that have kept the passes and eastern zones cold and cloudy. Instead, lower elevations on both sides of the range should warm, even if freezing levels appear a bit lower. While we expect plenty of sunshine across the mountains, pesky low clouds could linger particularly along the west slopes and near Snoqualmie Pass.
A high pressure ridge rebounds just offshore this evening bringing additional dry and stable air. This will allow for the return of easterly flow, temperature inversions, and low clouds/fog. As cold air once again settles into the Columbia River Basin, the freezing level forecasts get much more complicated. Expect strong inversions in the deep mountain valleys, passes, and along the east side of the range. Multiple freezing levels could form near Mt Hood and the other southern volcanoes.
Depending on your trailhead, it could be cold and socked in to start on Thursday. However, warmer sunnier weather exists above. Low clouds and valley fog may burn off along the west slopes of the Cascades, but expect it to stay entrenched in the passes and east of the crest. Even as freezing levels climb, the air mass isn't hot. Look for temperatures to hover in the mid to upper 30's. Enjoy the sunshine while you can. A potent fast moving system arrives Friday for a notable change in the weather.
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
Becoming mostly sunny with decreasing winds.
Wednesday
Night
Mostly clear with some low clouds and valley fog. Multiple freezing levels.
Wednesday
Cloudy in the morning with a few flurries possible. Then becoming mostly sunny with some lingering low clouds. Light to moderate W winds decreasing.
Wednesday
Night
Mostly clear with some low clouds and valley fog. Multiple freezing levels.
Wednesday
Cloudy in the morning with a few flurries possible. Then becoming mostly sunny with some lingering low clouds. Light to moderate W winds decreasing.
Wednesday
Night
Mostly clear with some low clouds and valley fog. Multiple freezing levels.
Wednesday
Cloudy in the morning with a few flurries or sprinkles possible. Then becoming mostly sunny with some lingering low clouds possible. Moderate and gusty NW winds decreasing.
Wednesday
Night
Mostly clear with some low clouds and valley fog. Multiple freezing levels with strong inversions, in the deeper valleys and passes.
Wednesday
Cloudy in the morning becoming partly to mostly sunny with some low clouds. West flow at pass level.
Wednesday
Night
Mostly clear with some low clouds and fog. Strong inversions at pass level. East flow.
Wednesday
Cloudy in the moring with a few sprinkles/flurries possible. Becoming partly to mostly sunny with patchy low clouds. Light to moderate but gusty NW winds decreasing. Weak west flow at pass level.
Wednesday
Night
Mostly clear with some low clouds and fog. Strong inversions at pass level. East flow.
Wednesday
Becoming mostly sunny. Light to moderate NW winds decreasing.
Wednesday
Night
Mostly clear with some low clouds and valley fog. Multiple freezing levels with strong inversions, in the deeper valleys and passes.
Wednesday
Mostly sunny with some lingering low clouds in the morning. Moderate and gusty NW winds decreasing
Wednesday
Night
Mostly clear with some low clouds and valley fog. Multiple freezing levels with strong inversions, in the deeper valleys and passes.
Wednesday
Becoming mostly sunny with a few low clouds. Moderate and gusty NW winds decreasing.
Wednesday
Night
Mostly clear with some low clouds and valley fog. Multiple freezing levels.
Wednesday
Cloudy in the morning quickly becoming partly to mostly sunny with patchy low clouds. moderate to strong and gusty NW winds decreasing slightly.
Wednesday
Night
Mostly clear with some low clouds and fog. Multiple freezing levels. Light to moderate N winds decreasing.
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).