We have a few light showers west of I-90, Mt Rainier and Mt Hood this morning leftover from an upper level trough that passed through Oregon last night. Isolated showers will quickly end as upper level ridging builds overhead. Areas of low clouds along the west slopes of the Cascades and near the Cascade Passes should slowly break up this morning. High clouds in advance from a weak north-south oriented frontal system offshore will move over the area today creating something between a high overcast with periods of filtered sunshine. Offshore flow will increase this afternoon ramping up moderate east - southeast winds both at Pass level and at ridgeline level for Stevens Pass and south to Mt Hood. This will also begin to pull cooler air west of the Cascade crest...dampening freezing levels late in the day. SE winds will peak for the same areas this evening.
The frontal system will bring light rain and snow to Mt Hood and the Olympics by daybreak. Expect light upslope snow and low clouds along the east-side of the Cascades which should be continuous but produce light accumulations. The front will pass through the Cascades around late morning or mid-day tomorrow with a switch to west flow behind the front. Precipitation amounts look rather light to moderate, generally 0.25-0.50" of water, and temperatures should cool in the afternoon as the shower activity wanes.
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
Thursday
High overcast with periods of filtered sunshine.
Thursday
Night
Increasing clouds with light rain and snow developing after midnight. Strong winds after midnight.
Thursday
Mostly clear then high clouds and filtered sunshine from late morning onward.
Thursday
Night
Mostly clear, then increasing clouds after midnight.
Thursday
Mostly clear then high clouds and filtered sunshine from late morning onward.
Thursday
Night
Mostly clear, then increasing clouds after midnight.
Thursday
Partly cloudy with areas of low clouds, then high clouds and filtered sunshine from late morning onward.
Thursday
Night
Mostly clear, then increasing clouds late in the evening. Strong winds after midnight.
Thursday
Partly cloudy with areas of low clouds, then high clouds and filtered sunshine from late morning onward.
Thursday
Night
Becoming cloudy with periods of light snow. Moderate to strong ESE ridgeline and Pass level winds.
Thursday
Partly cloudy with areas of low clouds, then high clouds and filtered sunshine from late morning onward.
Thursday
Night
Becoming cloudy with periods of light snow. Strong ESE ridgeline and Pass level winds.
Thursday
Mostly clear then high clouds and filtered sunshine from late morning onward.
Thursday
Night
Becoming cloudy with periods of light snow.
Thursday
Mostly clear then high clouds and filtered sunshine from late morning onward.
Thursday
Night
Becoming cloudy with periods of light snow.
Thursday
Mostly clear then high clouds and filtered sunshine from late morning onward.
Thursday
Night
Becoming cloudy with periods of light snow.
Thursday
Partly cloudy with areas of low clouds, then high clouds and filtered sunshine from late morning onward.
Thursday
Night
Becoming cloudy with light rain and developing around midnight.
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).