A strong occluded front passed through last night bringing heavy snow and strong winds to the region. The remnants of the front are hung up from over the southern Washington Cascades and Mt. Hood with showers in SW flow afflicting the central Cascades. We'll see a general tapering of steady precipitation over the Mt. Hood area today associated with the frontal band transition to those showers in SW flow by mid-day. An area of convergence currently in Skagit county will likely drop south towards Stevens Pass by mid-day before weakening. Showers will become lighter and more scattered but will continue for most areas for the rest of the day. For areas like Snoqualmie Pass that see a shift from E to W flow, look for a modest bump in temperatures and snow levels by Wednesday afternoon although still well below Pass level.
A new and weaker low pressure system will rotate up overnight and pass inland Thursday with an upper level trough overhead. This will continue snow showers for most areas through tomorrow, although there is some question to how far the moisture will push north overnight and on Thursday. The coldest temperatures and lowest snow levels will be found in the north Cascades with much colder interior air trying to push south and west. We'll likely see a period of moderate easterly winds later tonight and tomorrow before the low moves inland.
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
Cloudy with occasional light snow showers.
Wednesday
Night
Light to occasionally moderate snow showers.
Wednesday
Cloudy with occasional light snow showers except light to moderate in the morning.
Wednesday
Night
Light snow showers.
Wednesday
Light to occasionally moderate snow showers becoming lighter and scattered in the afternoon.
Wednesday
Night
Light to occasionally moderate snow showers.
Wednesday
Light to moderate snow showers becoming lighter and scattered in the afternoon.
Wednesday
Night
Light to occasionally moderate snow showers.
Wednesday
Light to occasionally moderate snow showers becoming lighter and scattered in the afternoon. Light east winds becoming west by mid-day at Pass level.
Wednesday
Night
Light to occasionally moderate snow showers. Light west winds becoming east overnight at Pass level.
Wednesday
Light to occasionally moderate snow showers becoming lighter and scattered in the afternoon. Light east winds becoming west by mid-day at Pass level.
Wednesday
Night
Light to occasionally moderate snow showers. Light west winds becoming east overnight at Pass level.
Wednesday
Mostly cloudy with light snow showers becoming scattered showers in the afternonon.
Wednesday
Night
Light snow showers.
Wednesday
Light to occasionally moderate snow showers becoming lighter and scattered in the afternoon. Showers heaviest near the Cascade crest.
Wednesday
Night
Light snow showers.
Wednesday
Light to occasionally moderate snow showers becoming lighter and scattered in the afternoon. Showers heaviest near the Cascade crest.
Wednesday
Night
Light snow showers.
Wednesday
Moderate to occasionally heavy snow becoming light to moderate snow showers in the afternoon. Strong 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).