A weak front passed through early this morning, bringing a welcome sight, snow(!) to some areas. 2-5" of snow has accumulated mainly across the west slopes of the Cascades with a snow level 2500-3500', with little to nothing along the east slopes of the Cascades. Precipitation is already tapering down, a trend that will continue through mid-day, except in the West Central zone, where occasional bouts of moderate snow will continue. Snow levels will rise slightly this afternoon.
We'll see a series of weather disturbances over the next few days, with the bulk of the precipitation aimed at British Columbia along with a slow warming trend. The next wave of moisture will arrive later this afternoon, with steady precipitation developing and continuing through Thursday morning. Look for snow levels to rise to 4000--4500' tonight. There's a slight chance for freezing rain near Snoqualmie Pass on Wednesday night and for areas just to the east, but if freezing rain does occur, it does not look like a significant icing event. Precipitation in the form of rain and snow will taper off Thursday afternoon and we'll see another bump in freezing levels during the afternoon.
With all of these systems, there's more uncertainty than usual in the precipitation forecasts, especially in central and southern areas. Right now, it appears that the southern zones, including the WA Cascades and Mt Hood, will see less precipitation through this period, but we'll be on the lookout for subtle shifts in the pattern.
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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Wednesday
Periods of light rain and snow this morning, becoming heavier in the afternoon. Moderate to occasionally strong ridgeline winds.
Wednesday
Night
Light to moderate rain and snow. Moderate to occasionally strong ridgeline winds.
Wednesday
Light to occasionally moderate rain and snow tapering off mid-day, and then increasing again in the afternoon. Moderate to occasionally strong ridgeline winds.
Wednesday
Night
Moderate rain and snow. Moderate to occasionally strong ridgeline winds.
Wednesday
Light to moderate rain and snow tapering off mid-day, and then increasing again in the afternoon. Moderate ridgeline winds.
Wednesday
Night
Moderate rain and snow. Moderate to occasionally strong ridgeline winds.
Wednesday
Light to occasionally moderate rain and snow tapering off mid-day, and then increasing again in the afternoon. Moderate ridgeline winds.
Wednesday
Night
Light to moderate rain and snow with a slight chance of freezing rain. Light E winds at Pass level, moderate SW ridgeline winds.
Wednesday
Light to occasionally moderate rain and snow tapering off mid-day, and then increasing again in the afternoon. Light E winds at Pass level and light to moderate SW ridgeline winds.
Wednesday
Night
Light to moderate rain and snow. Light E winds at Pass level, light to moderate SW ridgeline winds.
Wednesday
Light to occasionally moderate rain and snow tapering off mid-day, and then increasing again in the afternoon. Light E winds at Pass level and light to moderate SW ridgeline winds.
Wednesday
Night
Moderate rain and snow. Moderate to occasionally strong ridgeline winds.
Wednesday
Periods of light snow tapering off mid-day, and then increasing late in the afternoon. Light to moderate ridgeline winds.
Wednesday
Night
Light to moderate rain and snow, heavier near the crest. Moderate ridgeline winds.
Wednesday
Periods of light snow tapering off mid-day, and then increasing late in the afternoon. Light to moderate ridgeline winds.
Wednesday
Night
Light to moderate rain and snow, heavier near the crest. Moderate ridgeline winds.
Wednesday
Periods of light snow tapering off mid-day, and then increasing late in the afternoon. Light to moderate ridgeline winds.
Wednesday
Night
Light to moderate rain and snow, heavier near the crest. Moderate ridgeline winds.
Wednesday
Periods of light rain and snow tapering off mid-day, and then increasing late in the afternoon. Light to moderate ridgeline winds.
Wednesday
Night
Light to moderate 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).