A weak frontal system is beginning to undercut a strong ridge of high pressure that's been positioned over our area for several days. We won't see any precipitation today, but we will see a steady dose of high and mid clouds, with the opportunity for some filtered sunshine at times. Ridgeline winds have kicked up to moderate in most areas and should stay there for most of the day. Freezing levels have lowered relative to the last few days but will hang around 7000'. We'll continue to see low level inversions with areas of stratus and fog along the east slopes of the Cascades and up the Cascade Passes, squeezing through the Pass for Snoqualmie.
Offshore easterly flow will increase tonight and we'll see cold air dragged west of the Cascade crest, lowering freezing levels in the process and leading to moderate SE winds in many locations. The remnants of the front in the form of longwave upper level trough will pass through on Thursday, bringing about a chance for some light showers, especially for Mt Hood and the southern Olympics.
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
Partly sunny to mostly cloudy with periods of filtered sunshine. Light to occasionally moderate ridgeline winds.
Wednesday
Night
Mostly cloudy. Light to occasionally moderate ridgeline winds.
Wednesday
Partly sunny to mostly cloudy with periods of filtered sunshine. Moderate ridgeline winds.
Wednesday
Night
Mostly cloudy. Light to moderate ridgeline winds.
Wednesday
Partly sunny to mostly cloudy with periods of filtered sunshine. Light to occasionally moderate ridgeline winds.
Wednesday
Night
Mostly cloudy. Light to occasionally moderate ridgeline winds.
Wednesday
Partly sunny to mostly cloudy with periods of filtered sunshine. Light to moderate ridgeline winds.
Wednesday
Night
Mostly cloudy. Light to moderate ridgeline winds.
Wednesday
Partly sunny to mostly cloudy with periods of filtered sunshine upper slopes. Cooler with areas of low clouds and fog mainly east of the Pass. Light to occasionally moderate E winds at Pass level and WSW at ridgeline.
Wednesday
Night
Mostly cloudy. Light to moderate E-SE Pass level and ridgeline winds.
Wednesday
Partly sunny to mostly cloudy with periods of filtered sunshine upper slopes. Cooler with areas of low clouds and fog at and east of the Pass. Moderate E winds at Pass level and light to moderate WSW at ridgeline.
Wednesday
Night
Mostly cloudy. Moderate E-SE Pass level and ridgeline winds.
Wednesday
Partly sunny to mostly cloudy with periods of filtered sunshine. Light to occasionally moderate ridgeline winds.
Wednesday
Night
Cloudy. Light to moderate ridgeline winds.
Wednesday
Partly sunny to mostly cloudy with periods of filtered sunshine. Light to moderate ridgeline winds.
Wednesday
Night
Cloudy. Light to moderate ridgeline winds.
Wednesday
Partly sunny to mostly cloudy with periods of filtered sunshine. Light to moderate ridgeline winds.
Wednesday
Night
Cloudy. Light to moderate ridgeline winds.
Wednesday
Partly sunny to mostly cloudy with periods of filtered sunshine. Light to moderate ridgeline winds.
Wednesday
Night
Cloudy with a chance of light rain and snow. Light to 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).