A well-defined secondary low has formed in the PNW offshore waters, along a frontal boundary linked to a deep Gulf of Alaska low. An approaching warm front lacks the strength of the subsequent cold front. This warm front will increase light rain and snow from around Mt Rainier northward. Precipitation could reach moderate intensity in the Mt Baker area during the afternoon, enhanced by increasing moderate to locally strong S winds. Meanwhile, low-level light to moderate E flow creates some upslope snowfall and cooler temperatures along the east slopes of the Cascades. Warming and drying down-slope for most of the west slopes of the Cascades will delay the onset of precipitation in some areas. Expect snow levels in the 2000-3000 ft range.
The cold front moves through late Wednesday evening. S winds, along with light to moderate rain and snow (heavy at Mt Baker), peak before winds switch WSW and become more impactful for the mountain gaps, Mt Hood, and E slopes of the Cascades. Post-frontal light to moderate snow showers focus on areas near and west of the Cascade Crest through Thursday as snow levels lower from around 3000-3500 ft Wednesday evening to 2500 ft Thursday afternoon.
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 increasing light rain and snow. Increasing moderate ridgeline winds.
Wednesday
Night
Moderate rain and snow transitions to light showers from late evening onwards. Moderate ridgeline winds become light overnight.
Wednesday
Increasing light rain and snow becomes moderate late in the day. Increasing moderate ridgeline winds.
Wednesday
Night
Moderate to heavy rain and snow. Decreasing moderate ridgeline winds.
Wednesday
Increasing periods of light rain and snow. Increasing light to moderate ridgeline winds.
Wednesday
Night
Increasing moderate rain and snow. Increasing moderate ridgeline winds.
Wednesday
Periods of very light rain and snow in the morning increase in the afternoon. Increasing light to moderate ridgeline winds.
Wednesday
Night
Moderate rain and snow may be heavy at times for Paradise. Increasing moderate ridgeline winds.
Wednesday
Cloudy in the morning. Light rain and snow develop in the afternoon. Increasing light to moderate ridgeline and light E wind at the Pass.
Wednesday
Night
Increasing light rain and snow showers potentially become moderate overnight. Moderate ridgeline winds. Light to moderate E winds switch W at the Pass in the late evening hours.
Wednesday
Cloudy in the morning. Light rain and snow develop in the afternoon. Increasing light to moderate ridgeline and E wind at the Pass.
Wednesday
Night
Increasing light rain and snow showers potentially become moderate overnight. Moderate ridgeline winds. Light to moderate E winds switch W at the Pass in the late evening hours.
Wednesday
Increasing periods of light snow. Increasing light to moderate ridgeline winds.
Wednesday
Night
Light to occasionally moderate snow. Moderate ridgeline winds.
Wednesday
Increasing periods of light snow. Increasing moderate ridgeline winds.
Wednesday
Night
Light to occasionally moderate snow. Moderate ridgeline winds.
Wednesday
Mostly cloudy. Occasional light snow, mainly in the afternoon. Increasing light to moderate ridgeline winds.
Wednesday
Night
Light to moderate rain and snow decreases overnight. Moderate ridgeline winds.
Wednesday
Mostly cloudy with periods of light rain and snow in the afternoon. Light to moderate ridgeline winds.
Wednesday
Night
Moderate rain and snow. Moderate to 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).