A splitting system brings some (limited) moisture, plenty of cloudcover, and cooler temperatures back to the region Sunday and Monday.
A disorganized band of rain and snow continues to move into the southern Cascades this morning on SSE flow wrapping around an offshore closed low off the Oregon Coast. N flow further north turns NW and increases as the day progresses and weak troughing moves onshore. This shift will bring increasing chances for light rain and snow showers for the west slopes of the Cascades further north as well.
Light to moderate W and NW winds peak Sunday night into Monday morning and will accelerate through mountain gaps, the east slopes of the Cascades, and the SE side of volcanoes. They will also bring chances for light rain and snow showers along the west slopes of the Cascades. If precipitation develops in the central Washington Cascades, it is likely to focus on a weak convergence band.
Snow levels should fluctuate around 5000 ft Friday, 4000-4500 ft Friday night, and 3500-4000 ft further east. Expect somewhat warmer, drier air east of the Cascades throughout the period.
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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Sunday
Cloudy with periods of light rain or snow.
Sunday
Night
Partly cloudy with a slight chance of rain or snow showers.
Sunday
Mostly cloudy with a chance of light rain or snow showers.
Sunday
Night
Mostly cloudy with light rain or snow showers and weak convergence.
Sunday
Cloudy with a chance of light rain or snow showers.
Sunday
Night
Mostly cloudy with light rain or snow showers and weak convergence.
Sunday
Cloudy with a chance of light rain or snow showers.
Sunday
Night
Light rain or snow showers.
Sunday
Mostly cloudy with a chance of light rain or snow showers. Light ridgeline and W wind at the Pass.
Sunday
Night
Cloudy with a chance of rain or snow showers and weak convergence. Light to moderate ridgeline and light W wind at the Pass.
Sunday
Cloudy with a chance of light rain or snow showers. Increasing light to occasionally moderate ridgeline and W wind at the Pass.
Sunday
Night
Cloudy with a chance of rain or snow showers and weak convergence. Moderate ridgeline and light to moderate W wind at the Pass.
Sunday
Mostly cloudy.
Sunday
Night
Partly cloudy.
Sunday
Mostly cloudy.
Sunday
Night
Mostly cloudy with a slight chance of light rain or snow showers near the Cascade Crest.
Sunday
Cloudy with periods of light rain or snow.
Sunday
Night
Cloudy with light rain or snow showers near the Cascade Crest.
Sunday
Cloudy with periods of light rain or snow. Increasing light to moderate ridgeline winds.
Sunday
Night
Cloudy with light rain or snow showers. Moderate 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).