Forecast updated at 1000 to fix an error in the wind forecast at Hurricane Ridge.
A strong occluded frontal system at the leading edge of a deep trough continues to bring stormy weather and heavy mountain snowfall to the Pacific Northwest.
The front has reached Seattle as of 7 AM Saturday morning. The heaviest snowfall should occur during the morning hours as the front progresses ESE. The cold frontal passage shortly after 8 AM should shift cold low-level E flow to westerly through the mountain gaps, potentially resulting in a shift to rain for a portion of the day below 3500 ft at Snoqualmie Pass and along the east slopes of the Cascades. Cold air and moisture should continue to filter into the region behind the front with moderate to locally very intense, snow showers. Some convergence has already started to form (focused on the Mountain Loop northward). The heaviest snow will remain ahead, focusing increasingly on the southern Cascades and Mt. Hood as the day progresses.
Moderate snow showers continue Saturday night with further cooling and decreasing winds. A disturbance crosses the Cascades in the early morning hours, bringing a period of more organized snowfall.
Light to moderate snow showers continue on Sunday with snow levels below 1500 ft and light winds enabling high snow/water ratios.
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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Saturday
Moderate rain and snow early tampering to light snow showers as temperatures cool. Moderate winds gusting strong at ridgelines. Strong ridgeline wind gusts early in the day.
Saturday
Night
Moderate snow showers, increasing overnight.
Saturday
Heavy snow in the morning, becoming moderate snow showers. Strong ridgeline wind gusts early in the day.
Saturday
Night
Moderate snow showers heavy at times, increasing overnight.
Saturday
Heavy rain and snow tapering to moderate snow showers during the afternoon.
Saturday
Night
Moderate snow showers increasing overnight.
Saturday
Very heavy rain and snow at Paradise, becoming moderate in the afternoon. Decreasing moderate rain and snow at Crystal and White Passes. Strong ridgeline wind gusts.
Saturday
Night
Moderate snow showers, heaviest at Paradise and increasing overnight.
Saturday
Very heavy rain and snow tapering to moderate snow showers. Variable winds become light to moderate out of the west at the Pass. Strong ridgeline wind gusts.
Saturday
Night
Moderate snow showers, increasing overnight. Light to occasionally moderate W wind at the Pass.
Saturday
Very heavy rain and snow tapering to moderate snow showers. Variable winds become light to moderate out of the west at the Pass. Strong ridgeline wind gusts.
Saturday
Night
Moderate snow showers, increasing overnight. Light to occasionally moderate W wind at the Pass.
Saturday
Moderate to heavy rain and snow tapering to light to moderate snow showers in the afternoon. Moderate to strong ridgeline winds.
Saturday
Night
Light to moderate snow showers.
Saturday
Heavy rain and snow in the morning tapering to light to moderate rain and snow showers in the afternoon. Moderate to strong ridgeline winds.
Saturday
Night
Light snow showers.
Saturday
Decreasing moderate to heavy rain and snow. Moderate to strong ridgeline winds.
Saturday
Night
Light to moderate snow showers.
Saturday
Heavy to very heavy rain and snow. 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).