An atmospheric river continues to bring unseasonably warm air and heavy precipitation into the region. The first wave of moisture arrived Monday night with a front lingering over the region and maintaining heavy rain and upper elevation snow across the central Washington Cascades. Precipitation should increase across the Washington Cascades and lifts slightly northward through the afternoon as the next wave of moisture arrives with a low tracking just north of Vancouver Island by Monday evening. Lingering cold air pooled east of the Cascade Crest should continue to spill through the Cascade mountain gaps and will be cold enough to create freezing rain in places like Snoqualmie Pass through the morning hours. As the milder air and moderate SW winds continue to scour out the shallow cold air pool, freezing rain will increasingly become relegated to deep, cold valley locations and the Methow Valley. Precipitation should continue to be most intense for Snoqualmie Pass northward to highway 20 overnight. Washington Pass should see a changeover to all rain at the upper station after midnight.
On Wednesday, a stronger low well offshore lifts the deluge northward as a warm front moves into Canada, cutting off precipitation from south to north. This leaves our region cloudy and drier, but still very mild.
Ridgeline winds peak Tuesday evening and will be strong along parts of the east slopes of the Cascades. Rising snow levels should reach 7000-9000 ft by Wednesday.
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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Tuesday
Light rain and highest elevation snow becoming moderate in the afternoon.
Tuesday
Night
Moderate rain becoming light to moderate overnight.
Tuesday
Light rain and high elevation snow becoming moderate in the afternoon.
Tuesday
Night
Moderate rain and highest elevation snow decreasing overnight.
Tuesday
Heavy rain and high elevation snow.
Tuesday
Night
Heavy rain and highest elevation snow.
Tuesday
Moderate to heavy rain and high elevation snow; light to moderate at Crystal and Paradise.
Tuesday
Night
Heavy rain and high elevation snow; light to moderate at Crystal and Paradise.
Tuesday
Heavy rain and high elevation snow, possibly mixing freezing rain at times at the Pass. Light E winds at the Pass.
Tuesday
Night
Heavy rain and highest elevation snow. Variable and generally light winds at the Pass.
Tuesday
Heavy rain and high elevation snow. Freezing rain likely at Pass level through the morning hours. Light E winds at the Pass.
Tuesday
Night
Heavy rain and highest elevation snow. Variable and generally light winds at the Pass.
Tuesday
Moderate snow.
Tuesday
Night
Moderate snow mixing with rain or freezing rain at lower elevations and becoming light overnight.
Tuesday
Moderate to heavy rain and snow western part. Light rain and snow further east. Freezing rain likely in colder valley locations. Strong ridgeline wind gusts.
Tuesday
Night
Moderate to heavy rain and snow western part. Light rain and snow further east. Strong ridgeline winds.
Tuesday
Increasing light rain and highest elevation snow. Freezing rain possible in valley locations.
Tuesday
Night
Decreasing light rain.
Tuesday
Light rain and high elevation snow. Strong ridgeline wind gusts.
Tuesday
Night
Light rain and highest elevation snow. Strong ridgeline wind gusts.
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).