The swirl of a weak low pressure system just offshore of the Olympic peninsula continues to rotate showers into the region in WSW flow. The main focus for steadier shower activity is along the west slopes of the Cascades from roughly Hwy 2 to the Mt. Rainier area where snow levels have settled around 3500'. Near and especially south of this boundary are where the strongest westerly ridgeline winds can be found this morning, especially in the Mt Hood area. The low pressure will weaken today and pull slightly south. Showers will become scattered and lighter this afternoon. A clearing trend will begin for the north Cascades later this afternoon as the low pulls away. Moderate N ridgeline winds may develop for the higher terrain near the Methow Valley this afternoon and evening.
We may see an early evening shower near the west slopes of the central/southern WA Cascades before conditions completely dry out. Tuesday looks like a fair weather day with plenty of sunshine, generally light winds and afternoon freezing levels around 4000-5000'. With weak upper-level troughing over the area, we can't rule out an afternoon build-up in clouds or a slight chance of a PM shower over the Cascades.
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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Monday
Cloudy with scattered light rain and snow showers this morning, becoming partly to mostly cloudy in the afternoon.
Monday
Night
Partly to mostly clear.
Monday
Cloudy with scattered light rain and snow showers this morning, becoming partly to mostly cloudy in the afternoon.
Monday
Night
Partly to mostly clear.
Monday
Cloudy with light to occasionally moderate rain and snow showers this morning, becoming mostly cloudy with scattered light showers in the afternoon. Moderate ridgeline winds decreasing in the afternoon.
Monday
Night
Mostly cloudy with a slight chance of a light evening shower, then partly cloudy.
Monday
Cloudy with light to moderate rain and snow showers this morning, becoming mostly cloudy with scattered light showers in the afternoon. Moderate ridgeline winds decreasing in the afternoon.
Monday
Night
Mostly cloudy with a slight chance of a light evening shower, then partly cloudy.
Monday
Cloudy with light to occasionally moderate rain and snow showers this morning, becoming mostly cloudy with scattered light showers in the afternoon. Light to moderate ridgeline and Pass level W winds decreasing in the afternoon.
Monday
Night
Mostly cloudy with a slight chance of a light evening shower, then partly cloudy. Light and variable winds.
Monday
Cloudy with light to moderate rain and snow showers this morning, becoming mostly cloudy with scattered light showers in the afternoon. Moderate ridgeline and Pass level W winds decreasing in the afternoon.
Monday
Night
Mostly cloudy with a slight chance of a light evening shower, then partly cloudy. Light and variable winds.
Monday
Cloudy with scattered light rain and snow showers this morning, becoming partly to mostly sunny in the afternoon. Moderate ridgeline winds developing in the afternoon.
Monday
Night
Partly to mostly clear.
Monday
Cloudy with scattered light to occasionally moderate rain and snow showers this morning near the Cascade crest, becoming partly to mostly cloudy in the afternoon. Moderate ridgeline winds.
Monday
Night
Partly to mostly clear.
Monday
Cloudy with scattered light rain and snow showers this morning near the Cascade crest, becoming partly to mostly cloudy in the afternoon. Moderate ridgeline winds.
Monday
Night
Partly to mostly clear.
Monday
Cloudy with light to occasionally moderate rain and snow showers this morning, heaviest west side of the mountain, becoming mostly cloudy in the afternoon. Strong ridgeline winds becoming moderate in the afternoon.
Monday
Night
Mostly cloudy with a slight chance of a light evening shower, then partly cloudy.
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).