A cold front slowly crosses the region from north to south Tuesday and Tuesday night. As of Tuesday morning, light rain and snow has spread across the west slopes of the Cascades. Snow levels sit near 3000 ft in the central Washington Cascades and may lower slightly during the day as the cold front ushers in gradual cooling. As the front drops southward, the northerly low-level flow should enhance upslope snowfall in favored areas of the east slopes of the Cascades such as the Wenatchee Mountains.
Light snow gradually decreases from north to south Tuesday night, but moderate snow developing late morning on Tuesday may continue through Tuesday night in the Mt. Hood area before becoming light Wednesday morning and generally ending by the afternoon. Snow amounts should be in the 3-6" range for the central Cascade above 3500 ft with the marginal rain/snow line limiting snow totals at Snoqualmie Pass level. Mt. Hood could pick up 8-12" of snow by late Wednesday.
Clearing skies should move in slowly from N to S. Mt. Baker should clear Tuesday afternoon with the Olympics and Washington Pass region clearing Tuesday night. Expect partly sunny or sunny weather across much of Washington State by Wednesday.
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 and snow tapering to flurries during the afternoon.
Tuesday
Night
Mostly cloudy with isolated snow flurries.
Tuesday
Periods of decreasing light snow in the morning, then becoming mostly cloudy.
Tuesday
Night
Mostly cloudy with isolated snow flurries.
Tuesday
Decreasing light rain and snow.
Tuesday
Night
Mostly cloudy with isolated snow flurries.
Tuesday
Light rain and snow.
Tuesday
Night
Light snow.
Tuesday
Decreasing light rain and snow. Light W wind at the Pass.
Tuesday
Night
Periods of very light snow. Light E winds at the Pass.
Tuesday
Decreasing light rain and snow. Light W wind at the Pass.
Tuesday
Night
Periods of very light snow. Light E winds at the Pass.
Tuesday
Very light snow at times.
Tuesday
Night
Partly cloudy.
Tuesday
Increasing periods of light snow.
Tuesday
Night
Decreasing light snow.
Tuesday
Increasing periods of light snow.
Tuesday
Night
Light snow at times.
Tuesday
Increasing light snow becoming moderate. Moderate to 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).