A historic and long-duration rainfall event continues across our region as an atmospheric river brings very warm, moist air to Washington State. Seemingly defying the laws of physics, Washington Pass continues to pick up snowfall, but it is likely to change to rain at some point on Wednesday and at the very latest, Wednesday evening. Most other areas are measuring rainfall in inches from Mt Rainier northward, but also Mt St Helens and Mt Adams. The combination of strong WSW winds and the moist air leads to very strong vertical motion and a very effective squeegee of the moist air as it arrives on a strong jetstream. The strong winds also continue to a lot of moisture over onto the east slopes of the ranges. This combination is leading to major river flooding and has already led to some historic river flows. The most intense rainfall is likely to shift north today and focus from Snoqualmie Pass to Mt Baker. It could ease slightly at Snoqualmie Pass in the afternoon, but that remains to be seen.
The focus of the precipitation remains focused on the central and northern portions of Washington State in the evening, but shifts back slightly southward overnight with a cooling trend. Ridgelines around Mt Baker and Washington Pass should turn back to snow. The cooler, drying trend continues over northern Washington as moderate to heavy precipitation becomes light to moderate by the afternoon and may shut off in the northern part of the state. Most areas won't pick up more than an inch or two of snow with the cooling trend.
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
Wednesday
Heavy rain. Increasing moderate ridgeline winds, strong gusts.
Wednesday
Night
Moderate to heavy rain and higher elevation snow.
Wednesday
Very heavy rain and highest elevation snow. Increasing moderate ridgeline winds, strong gusts
Wednesday
Night
Very heavy rain and higher elevation snow. Moderate to strong ridgeline winds.
Wednesday
Very heavy rain and highest elevation snow. Increasing moderate to strong ridgeline winds.
Wednesday
Night
Very heavy rain and high elevation snow. Moderate to strong ridgeline winds.
Wednesday
Very heavy rain and highest elevation snow. Increasing moderate to strong ridgeline winds.
Wednesday
Night
Heavy rain and higher elevation snow, very heavy at Paradise. Moderate to strong ridgeline winds.
Wednesday
Very heavy rain. Increasing moderate to strong ridgeline and light to moderate W wind at the Pass.
Wednesday
Night
Very heavy rain and higher elevation snow. Moderate to strong ridgeline and light to moderate W wind at the Pass.
Wednesday
Very heavy rain. Increasing moderate to strong ridgeline and moderate W wind at the Pass.
Wednesday
Night
Very heavy rain and higher elevation snow. Moderate to strong ridgeline and moderate W wind at the Pass.
Wednesday
Very heavy rain and higher elevation snow. Rising snow levels. Moderate to strong ridgeline winds.
Wednesday
Night
Very heavy rain and higher elevation snow. Moderate to strong ridgeline winds.
Wednesday
Heavy rain. Strong ridgeline winds, extreme gusts.
Wednesday
Night
Moderate to heavy rain. Strong ridgeline winds, extreme gusts.
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).