The Pacific Northwest is entering a prolonged period of quiet weather. A low to our south has detached from the jetstream. Moisture to the north of the low continues some light to locally moderate snowfall around Mt. Hood which should decrease as the day continues. NW winds develop as the upper low drops south toward California and should keep the band of moisture from progressing much further north before dissipating during the evening hours. The northerly flow aloft should bring colder temperatures into the region overnight as a ridge of high pressure moves into the nearshore water and continues a clearing trend across the region. Northerly flow and mostly clear skies continue on Tuesday, with some low clouds trapped below 4000-5000 ft along the W slopes of the Cascades.
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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Sunday
Mostly cloudy in the morning, then becoming partly cloudy.
Sunday
Night
Low clouds with mostly clear skies above.
Sunday
Mostly cloudy with decreasing clouds during the afternoon.
Sunday
Night
Mostly clear. Brisk NE Fraser outflow winds in northern part of zone.
Sunday
Partly cloudy.
Sunday
Night
Mostly cloudy.
Sunday
Mostly cloudy with increasing chances of light snow primarily in the Crystal Mountain area.
Sunday
Night
Mostly cloudy with chances of light snow primarily in the Crystal Mountain area.
Sunday
Mostly cloudy with a chance of a snow flurry/sprinkle. Light NW ridgeline winds developing with E low-level flow switching W by the afternoon.
Sunday
Night
Mostly cloudy with a chance of a snow flurry/sprinkle. Light to occasionally moderate NW ridgeline winds with light low-level W winds.
Sunday
Mostly cloudy with a chance of a snow flurry/sprinkle. Light NW winds developing with E low-level flow switching W by the afternoon.
Sunday
Night
Mostly cloudy with a chance of a snow flurry/sprinkle. Light to occasionally moderate NW ridgeline winds with light low-level W winds.
Sunday
Mostly cloudy to start with clouds decreasing.
Sunday
Night
Mostly clear.
Sunday
Partly cloudy with clear skies to the east.
Sunday
Night
Partly cloudy with clear skies to the east.
Sunday
Mostly cloudy with a chance of light rain/snow.
Sunday
Night
Mostly cloudy with decreasing chances of light rain/snow.
Sunday
Periods of light to moderate snow in the morning decreases in the afternoon.
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).