A front remains stalled off the Pacific Northwest coastline on Tuesday as a low develops along it and tracks towards our nearshore waters. This will leave most of our region relatively dry within the warm sector. The exception will be light rain and snow continuing over the Olympics and the Mt Baker area throughout the day, along with mostly cloudy skies to other areas. The best chance of more significant clearing will be during southern portions of the forecast region during the mid-day hours. Late in the day, light rain and snow spread throughout the Cascades. SW winds gradually shift more southerly as the day progresses.
Light to occasionally moderate rain and snow increase Tuesday night as the offshore low tracks toward Vancouver Island. With light (but not cold) E low-level flow, snow levels should be near Snoqualmie Pass elevation.
Snow levels rise up to 3000-4000 ft as the front moves onshore on Wednesday with continued light to moderate rain and snow. Expect some cooling in for the Olympics and then the Cascades late in the day.
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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Tuesday
Periods of light rain or snow focus on the SW Olympics with minimal spillover into the northern and eastern Olympics.
Tuesday
Night
Light rain and snow. Increasing light ridgeline winds become moderate.
Tuesday
Light snow. Moderate ridgeline winds.
Tuesday
Night
Increasing moderate rain and snow. Moderate ridgelin winds become strong at times overnight.
Tuesday
Mostly cloudy with periods of very light rain and snow.
Tuesday
Night
Light to occasionally moderate rain and snow.
Tuesday
Partly to mostly cloudy skies in the morning. Clouds thicken in the afternoon with light rain and snow developing late in the day.
Tuesday
Night
Light to moderate rain and snow. Light to moderate ridgeline winds.
Tuesday
Partly to mostly cloudy with light rain and snow possible late in the day. Light ridgeline and W wind at the Pass.
Tuesday
Night
Periods of light rain and snow. Light ridgeline and E wind at the Pass.
Tuesday
Partly to mostly cloudy with light rain and snow possible late in the day. Light to occasionally moderate ridgeline and light W wind at the Pass.
Tuesday
Night
Periods of light rain and snow. Light ridgeline and E wind at the Pass.
Tuesday
Mostly cloudy. Light rain and snow possible late in the day.
Tuesday
Night
Periods of light rain and snow.
Tuesday
Mostly cloudy. Light rain and snow possible late in the day.
Tuesday
Night
Periods of light rain and snow.
Tuesday
Mostly cloudy. Light rain and snow possible late in the day.
Tuesday
Night
Periods of light rain and snow.
Tuesday
Mostly cloudy. Light rain and snow possible late in the day. Moderate ridgeline winds.
Tuesday
Night
Periods of light rain and snow. Moderate 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).