Happy New Year from all of us at NWAC! This may not be exactly what you had envisioned for the start of 2021; warm frontal precipitation and rising snow levels will sum up today. Precipitation and winds will be the heaviest/strongest for the northwest Cascades including Mt Baker and the Olympics. Areas from about I-90 and south should see a few hours of drier and mild weather today as we wait for the associated cold front to arrive. Snow levels will rise to 5000-7000' across the region with slightly cooler snow levels for the Washington Pass area.
The front should pass through the Cascades around 7- 8 pm bringing a burst of moderate precipitation for all areas through the evening hours. Post-frontal showers will follow and favor the west slopes of the Cascades overnight as snow levels slowly lower to 4000-4500'.
There will hardly be time to catch your breath before the next system arrives on Saturday, bringing increasing precipitation during the day region-wide. This system has an impressive amount of precipitable water to drop on us and Saturday is part 1 of the storm with part 2 arriving Saturday night. Snow levels will be fairly uniform across the region on Saturday. Look for a slow but steady increase in snow levels during the day as winds ramp up as well.
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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Friday
Light to moderate rain and snow. Strong winds.
Friday
Night
Moderate rain and snow becoming scattered snow showers late in the evening.
Friday
Moderate to occasionally heavy rain and snow. Winds becoming strong mid-day.
Friday
Night
Moderate to occasionally heavy rain and snow becoming moderate showers late in the evening.
Friday
Moderate rain and snow. Winds becoming strong mid-day.
Friday
Night
Moderate to occasionally heavy rain and snow becoming moderate showers late in the evening.
Friday
Light rain and snow this morning, locally moderate at Paradise, then cloudy. Rain and snow returning late in the day.
Friday
Night
Moderate rain and snow becoming light to moderate showers late in the evening.
Friday
Periods of light to occasionally moderate rain and snow. Light east winds at Pass level.
Friday
Night
Moderate rain and snow becoming light to occasionally moderate showers late in the evening. Moderate west winds at Pass level.
Friday
Light to moderate rain and snow this morning, then cloudy. Rain and snow returning late in the day. Light to moderate east winds at Pass level.
Friday
Night
Moderate rain and snow becoming light to moderate showers late in the evening. Moderate west winds at Pass level.
Friday
Light to occasionally moderate rain and snow, heavier near the Cascade crest.
Friday
Night
Light to moderate rain and snow becoming scattered light showers late in the evening.
Friday
Periods of light to occasionally moderate rain and snow in the morning then cloudy.
Friday
Night
Light to moderate rain and snow becoming scattered light showers late in the evening.
Friday
Periods of light to occasionally moderate rain and snow in the morning then cloudy.
Friday
Night
Light to moderate rain and snow becoming scattered light showers late in the evening.
Friday
Periods of light to occasionally moderate rain and snow in the morning then cloudy.
Friday
Night
Moderate rain and snow becoming light to moderate showers late in the evening.
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).