A closed low-pressure center off the NW Oregon coastline will drift northward on Sunday. Moisture wrapping around the low should bring light to occasionally moderate rain and snow to Mt. Hood, the southern Washington Cascades, and the SE Olympics this morning. Light rain and snow should expand into the central Cascades during the afternoon. Light E low-level flow should enhance precipitation slightly for the E slopes of the Cascades, but S flow aloft should focus the heavier precipitation on the volcanoes. Expect gradual cooling from south to north as the low shifts northward.
The closed low reaches NW Washington Sunday night with SW flow bringing in more moisture and moderate rain/snow for the Washington Volcanoes and west slopes of the Cascades while the E flow continues to diminish, so precipitation totals along the east slopes should remain light.
The remains of the low circulation drift into British Columbia on Monday, with very light W flow maintaining clouds and light precipitation for the W slopes of the Cascades while the E slopes can expect increasing sunshine. Snow levels should drop to around 3000 ft.
Overall, this storm could bring 1-4" of snow to the E slopes of the Cascades with 6-10" of snow for Mt Hood and Mt Baker. Paradise should be the winner for snow totals with around 1 ft of snow.
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
Increasing occasional light rain/snow for the northern Olympics with more continuous rain/snow for the SE Olympics.
Sunday
Night
Light rain and snow.
Sunday
Cloudy with a slight chance of light rain/snow developing late in the day.
Sunday
Night
Increasing light to moderate rain and snow.
Sunday
Cloudy with a slight chance of light rain/snow developing late in the day.
Sunday
Night
Increasing light to moderate rain and snow.
Sunday
Increasing light rain and snow (becoming moderate by the afternoon at Paradise).
Sunday
Night
Light rain and snow (moderate to heavy at Paradise).
Sunday
Cloudy in the morning with light rain and snow developing during the afternoon. Light to moderate ridgeline and light E winds at the Pass.
Sunday
Night
Light rain and snow. Light ridgeline and E wind at the Pass.
Sunday
Cloudy in the morning with light rain and snow developing during the afternoon. Moderate ridgeline and light E winds at the Pass.
Sunday
Night
Light rain and snow. Light ridgeline and E wind at the Pass.
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).