A low pressure system stalled off the coast continues to rotate showers into the area this morning. Most of the precipitation is focused in the Olympics and western foothills of the Cascades. The low will finally drift southward today and drag most of the moisture with it. While many places may start the day with lots of clouds, the general trend will be for drying and clearing. An unstable atmosphere overhead allows daytime warming to help reinvigorate showers in the afternoon and create some popcorn cumulus clouds. Precipitation should be most prevalent north of I-90 in the eastern forecast zones. As flow shifts more northerly, showers will approach from the N or NE.
While a few flurries and sprinkles could linger into the early evening, the majority of locations stay dry overnight. Mostly clear skies will allow temperature inversions to develop in the mountain valleys and passes, along with patchy valley fog. A high pressure ridge approaches the region on Saturday. Expect plenty of sunshine, light winds, and warm (but not hot) temperatures. The dry and warm pattern should stay with us at least through early next week.
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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Friday
Cloudy with light to moderate showers. Heaviest along the southern and western Olympics. Showers decreasing in the afternoon becoming partly sunny.
Friday
Night
Mostly clear with temperature inversions in the mountain valleys.
Friday
Cloudy with showers in the morning. Light to moderate S winds decreasing. Becoming partly to mostly sunny with scattered showers in the afternoon.
Friday
Night
Mostly clear with temperature inversions in the mountain valleys.
Friday
Cloudy with showers in the morning. Becoming partly to mostly sunny with scattered showers in the afternoon.
Friday
Night
Mostly clear with temperature inversions in the mountain valleys.
Friday
Cloudy with a few light showers in the morning. Becoming partly to mostly sunny in the afternoon with a few isolated showers possible.
Friday
Night
Mostly clear with temperature inversions in the mountain valleys and passes.
Friday
Mostly cloudy with a few showers possible in the morning. Becoming partly to mostly sunny with a few isolated showers possible in the afternoon. Light and variable winds.
Friday
Night
Mostly clear with temperature inversions in the Pass. Patchy fog possible. Light E flow at pass level.
Friday
Mostly cloudy with a few showers possible in the morning. Becoming partly to mostly sunny with a few isolated showers possible in the afternoon. Light and variable pass level winds.
Friday
Night
Mostly clear with temperature inversions and patchy fog. Light E flow at pass level.
Friday
Mostly cloudy in the morning. Mostly sunny with isolated convective showers possible in the afternoon.
Friday
Night
A few showers lingering into the early evening. Then mostly clear with temperature inversions in the mountain valleys and passes.
Friday
Mostly cloudy in the morning. Mostly sunny with isolated convective showers possible in the afternoon.
Friday
Night
Mostly clear with temperature inversions in the mountain valleys and passes.
Friday
Mostly cloudy in the morning. Mostly sunny with isolated convective showers possible in the afternoon.
Friday
Night
Mostly clear with temperature inversions in the mountain valleys and passes.
Friday
Mostly cloudy in the morning. Becoming partly to mostly cloudy. A few flurries possible throughout the day.
Friday
Night
Partly to mostly clear. Light to moderate NE 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).