A warm frontal extending from a low pressure system off the SE coast of Alaska has spread high clouds over the area. Light steady precipitation is moving over the Olympic peninsula and the northwest Cascades this morning. The precipitation shield will extend further south as the day wears on, with light precipitation becoming moderate toward the late afternoon hours over Washington State. Ridgeline winds out of the SW or W will also increase later in the day.
The main event will be tonight as the frontal boundary sags south and passes through the Cascades during the early morning hours of Monday. This should bring up to a foot of snow along the west slopes of the Cascades and Mt Hood above 3000' along with a bout of strong west winds throughout the region. A Puget Sound convergence zone may add a few additional inches tomorrow morning between I-90 and Hwy 2. A broad upper-level trough axis will swing inland on Monday afternoon. This will help keep our region cool, cloudy, and showery throughout the day. Sunbreaks are more likely further east of the Cascade crest and over the Olympics tomorrow afternoon.
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
Sunday
Light rain and snow developing this morning, becoming light to occasionally moderate in the afternoon. Ridgeline winds becoming strong in the afternoon.
Sunday
Night
Light to moderate rain and snow becoming showers after midnight. Strong ridgeline winds.
Sunday
Light rain and snow becoming light to moderate in the afternoon. Ridgeline winds becoming strong late in the afternoon.
Sunday
Night
Moderate to occasionally heavy rain and snow becoming showers late tonight. Strong ridgeline winds.
Sunday
Light rain and snow developing this morning, becoming light to occasionally moderate in the afternoon. Increasing ridgeline winds in the afternoon.
Sunday
Night
Moderate to occasionally heavy rain and snow becoming showers late tonight. Strong ridgeline winds.
Sunday
Cloudy with light rain and snow developing around mid-day. Increasing ridgeline winds in the afternoon.
Sunday
Night
Moderate to locally heavy rain and snow becoming showers late tonight. Heaviest precipitation Paradise area. Strong ridgeline winds.
Sunday
Light rain and snow developing this morning, becoming light to occasionally moderate in the afternoon. Increasing ridgeline winds in the afternoon. Light to moderate west winds at Pass level.
Sunday
Night
Moderate rain and snow becoming showers late tonight. Strong ridgeline winds.
Sunday
Light rain and snow developing this morning, becoming light to occasionally moderate in the afternoon. Increasing ridgeline winds in the afternoon. Light to moderate west winds at Pass level.
Sunday
Night
Moderate to occasionally heavy rain and snow becoming showers late tonight. Strong ridgeline winds.
Sunday
Light rain and snow developing late morning. Increasing ridgeline winds in the afternoon.
Sunday
Night
Light to moderate rain and snow becoming showers late tonight. Strong ridgeline winds.
Sunday
Cloudy with light rain and snow developing around mid-day. Increasing ridgeline winds in the afternoon.
Sunday
Night
Light to moderate rain and snow becoming showers late tonight. Strong ridgeline winds.
Sunday
Cloudy with light rain and snow developing around mid-day. Increasing ridgeline winds in the afternoon.
Sunday
Night
Light to occasionally moderate rain and snow becoming showers late tonight. Strong ridgeline winds.
Sunday
Cloudy with light rain and snow developing in the afternoon.
Sunday
Night
Moderate to occasionally heavy rain and snow becoming showers late tonight. Strong 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).