A front passed through the Cascades last night switching the prevailing flow from south-southeast to the southwest. Cooler air behind the front has dropped snow levels to near 2000' in the Olympics and northwest Cascades. Snow levels will take a bit longer to dip along the east slopes of the Cascades as cooler air filters in today. Scattered showers will continue this morning for most areas. A compact upper level shortwave feature can be seen on satellite and radar rotating to the SW of the Olympic peninsula. As this feature lifts NE today across the central Cascades, it will enhance shower activity over the region. The upper level lift combined with an increasingly cool and unstable air mass will help support showers and clouds over all areas. Winds will strong for the Mt Hood area and the south/central Washington Cascades south of about I-90.
The trailing stacked low pressure system and upper level trough will dig south along the Oregon coast tonight. This will spread steadier light snow in southwest Washington Cascades and especially Mt Hood. With low snow levels this should produce several inches of lower density snow for these areas.
As the low pulls away, we'll see a drying trend from north to south start late Tuesday night and continue through the day on Wednesday. WIth upper-level ridging building offshore, there remains to be seen how much low level moisture will result in low level marine clouds trapped along the west slopes of the Cascades in the afternoon.
Weather Forecast
Olympics
West North
West Central
West South
Stevens Pass
Snoqualmie Pass
East North
East Central
East South
Mt. Hood
Use dropdown to select your zone
Tuesday
Cloudy with light snow showers becoming light to moderate in the late morning.
Tuesday
Night
Cloudy with light snow showers in the evening, becoming mostly cloudy after midnight.
Tuesday
Cloudy with light to moderate snow showers.
Tuesday
Night
Cloudy with light to occasionally moderate snow showers in the evening, becoming mostly cloudy after midnight.
Tuesday
Cloudy with light to moderate snow showers.
Tuesday
Night
Cloudy with light to occasionally moderate snow showers in the evening, becoming mostly cloudy after midnight.
Tuesday
Cloudy with light to moderate rain and snow showers.Showers heaviest Paradise area in the afternoon. Increasing ridgeline winds.
Tuesday
Night
Cloudy with light to occasionally moderate snow showers.
Tuesday
Cloudy with light rain and snow showers becoming light to moderate snow showers in the afternoon. Light east winds at Pass level becoming moderate west winds in the afternoon.
Tuesday
Night
Cloudy with light to occasionally moderate snow showers in the evening. Showers tapering off after midnight. Light east winds at Pass level.
Tuesday
Cloudy with light rain and snow showers becoming light to moderate snow showers in the afternoon. Light east winds at Pass level becoming moderate west winds in the afternoon.
Tuesday
Night
Cloudy with light to occasionally moderate snow showers in the evening. Showers tapering off after midnight. Light east winds at Pass level.
Tuesday
Cloudy with light to occasionally moderate rain and snow showers.
Tuesday
Night
Cloudy with scattered light snow showers in the evening, becoming partly cloudy after midnight.
Tuesday
Scattered light rain and snow showers. Mostly cloudy this morning, becoming cloudy this afternoon.
Tuesday
Night
Cloudy with scattered light snow showers in the evening, becoming partly cloudy after midnight.
Tuesday
Scattered light rain and snow showers. Mostly cloudy this morning, becoming cloudy this afternoon.
Tuesday
Night
Cloudy with light to occasionally moderate snow showers.
Tuesday
Scattered light to occasionally moderate rain and snow showers increasing in the afternoon. Cloudy west side of Mt Hood, mostly cloudy east side. Increasing 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).