A N-S oriented cold front currently transits the Cascades as of 7 AM Sunday morning. It brings a band of light to moderate snow that will continue in some areas until 8 or 9 AM. Behind the front, continuous bands of snow have moved onshore over western Washington. These bands will bring locally intense snow at times, graupel, and possibly even small hail as temperatures cool aloft and the atmosphere becomes more unstable. Expect breaks of sun between squall line bands. Mt. Baker and the Mountain Loop areas may pick up 3-6" of snow today with other areas expecting 1-3". The system should continue to bring areas of moderate ridgeline winds with strong winds reported at Crystal Summit and Mission Summit Sunday morning. Strong winds may also develop at upper elevations around White Pass.
Light snow shower should taper off this evening, leaving partly clearing skies with a primary upper low spinning southward offshore. Temperatures should become quite cold with snow levels approaching sea level by the early morning hours in some areas.
On Monday, the upper low should bring increasing light snow shower activity into the southern parts of the forecast region. Generally, 0-2" of snow are expected from I-90 south to Mt. Hood while other areas remain dry.
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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Sunday
Light, but locally intense, snow showers.
Sunday
Night
Light snow showers in the evening, then becoming mostly clear.
Sunday
Moderate snow in the morning. Moderate but locally intense snow showers in the afternoon.
Sunday
Night
Light snow showers in the evening, then becoming partly cloudy.
Sunday
Light to moderate snow in the morning transitioning to locally intense snow showers in the afternoon.
Sunday
Night
Light snow showers in the evening then becoming partly to mostly clear.
Sunday
Light snow becoming snow showers, locally intense at times. Heaviest at Paradise.
Sunday
Night
Light snow showers in the evening, then remaining mostly cloudy.
Sunday
Light snow showers, locally intense at times.
Sunday
Night
Light snow showers in the evening, then becoming partly cloudy.
Sunday
Light snow showers, locally intense at times.
Sunday
Night
Light snow showers in the evening, then becoming partly cloudy.
Sunday
Light snow showers, locally intense at times.
Sunday
Night
Light snow showers possible in the evening then becoming partly to mostly clear.
Sunday
Light snow showers, locally intense at times near the Cascade Crest.
Sunday
Night
Light snow showers in the evening then becoming partly cloudy.
Sunday
Light snow showers, locally intense at times.
Sunday
Night
Light snow showers in the evening then remaining mostly cloudy.
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).