A strong frontal system is poised to pass through the central Cascades between 3-4 pm. Snowfall rates, already over an inch an hour in the Mt Baker area will spread south to the south Washington Cascades in the afternoon. Look for snow levels to drop quickly with and behind the front, snow levels should be near or below 2500' across Washington state by 5 pm this afternoon and drop further tonight, to 500-1000'.
There is a strong low-level jet out ahead of the frontal system, extreme W-SW winds will develop in most areas during the day. Mt Hood will see the winds this afternoon but the heaviest precipitation will hold off until this evening.
A Puget Sound Convergence zone will likely wallop the Hwy 2 corridor this evening behind the front. There's less certainty if the convergence zone will dip south and refocus on the Snoqualmie Pass area after midnight. This storm will produce widespread 6-12 inches above 4000', with locally higher totals for Mt Baker and where the convergence zone settles longest.
We'll be on the back-side of a cool upper trough tomorrow, expect showery and cloudy conditions.
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 to moderate rain and snow becoming light to occasionally moderate showers in the afternoon. Strong winds.
Sunday
Night
Mostly cloudy with scattered light rain and snow showers.
Sunday
Moderate to heavy rain and snow becoming moderate showers mid-afternoon. Strong winds becoming strong to extreme late morning.
Sunday
Night
Cloudy with light to moderate snow showers in the evening becoming scattered light snow showers after midnight.
Sunday
Light rain and snow developing, becoming moderate mid-day, then moderate showers late in the afternoon. Strong winds becoming strong to extreme late morning.
Sunday
Night
Light to moderate snow showers. Strong to extreme winds decreasing late.
Sunday
Light rain and snow developing mid-day, becoming moderate in the afternoon. Strong winds becoming strong to extreme this afternoon.
Sunday
Night
Light to moderate snow showers. Strong to extreme winds decreasing late.
Sunday
Light rain and snow developing late morning, becoming moderate in the afternoon, becoming moderate to occasionally heavy showers late. Strong winds becoming strong to extreme this afternoon.
Sunday
Night
Moderate snow showers, occasionally heavy in the evening. Strong to extreme winds decreasing late.
Sunday
Light rain and snow developing late morning, becoming moderate in the afternoon, becoming moderate to occasionally heavy showers late. Strong winds becoming strong to extreme this afternoon.
Sunday
Night
Moderate snow showers. Strong to extreme winds decreasing late.
Sunday
Light rain and snow, becoming moderate in the afternoon, then light to moderate showers late. Strong to extreme winds.
Sunday
Night
Mostly cloudy with scattered light to occasionally moderate snow showers.
Sunday
Light rain and snow developing late morning, becoming light to moderate in the afternoon. Strong winds becoming strong to extreme winds in the afternoon.
Sunday
Night
Mostly cloudy with scattered light snow showers, except cloudy with moderate showers near the Cascade crest. Strong to extreme winds.
Sunday
Light rain and snow developing mid-day, becoming moderate late. Strong winds becoming strong to extreme winds in the afternoon.
Sunday
Night
Mostly cloudy with scattered light snow showers, except cloudy with moderate showers near the Cascade crest. Strong to extreme winds.
Sunday
Cloudy. Light rain and snow developing early afternoon, becoming moderate late. Strong winds increasing and becoming extreme in the afternoon.
Sunday
Night
Moderate to occasionally heavy snow showers. Strong to extreme 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).