The tail end of last night's atmospheric river will continue to deliver moderate to locally heavy precipitation across the west slopes of the Cascades south of Hwy 2 to Mt Hood through this morning, with lighter rain/snow elsewhere. Snow levels have dipped down to 4000' in the north Cascades, 5000/5500' in the central/south Cascades and 7000-7500' for Mt Hood.
After a bit of a lull later this morning, we'll see another round of heavier precipitation mid-day into the afternoon as a new frontal wave pushes into the area. The heaviest precipitation during the daylight hours will once again be focused on the south/central WA Cascades and Mt Hood with lighter amounts further north and east. Snow levels will rise about 500-1000' vs this morning. The front will lift through Sunday evening, spreading heavier precipitation further north. Look for very strong to extreme W-SW winds later this afternoon and evening with this feature.
We'll see a bit of a break in the action late tonight through Monday morning as snow levels fall to around 3500', with milder snow levels for Mt Hood. A warm front will lift through mid-day Monday and Monday afternoon, bringing a new round of light to moderate precipitation with a potential bullseye for the south WA Cascades. Snow levels will be a bit cooler with this system, so we can look forward to more mid-elevation snow than rain.
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
Periods of light rain and snow, increasing in the afternoon. Light to moderate ridgeline winds becoming strong in the afternoon.
Sunday
Night
Light to moderate rain and snow easing after midnight. Strong ridgeline winds easing after midnight.
Sunday
Periods of light rain and snow, increasing in the afternoon. Light to moderate ridgeline winds increasing in the afternoon.
Sunday
Night
Moderate to heavy rain and snow easing after midnight. Strong ridgeline winds easing after midnight.
Sunday
Periods of light rain and snow, increasing to moderate in the afternoon. Light to moderate ridgeline winds increasing in the afternoon.
Sunday
Night
Moderate rain and snow easing after midnight. Strong ridgeline winds easing after midnight.
Sunday
Moderate to occasionally heavy rain and snow this morning, easing late morning, then becoming moderate to locally heavy mid-day. Moderate ridgeline winds becoming strong in the afternoon.
Sunday
Night
Light to moderate rain and snow easing after midnight. Strong ridgeline winds easing after midnight.
Sunday
Light to moderate rain and snow this morning, easing late morning, then becoming moderate early afternoon. Moderate ridgeline W winds becoming SSE in the afternoon. Light east winds at Pass level.
Sunday
Night
Light to moderate rain and snow easing after midnight. Strong W ridgeline and Pass level winds easing after midnight.
Sunday
Moderate to occasionally heavy rain and snow this morning, easing late morning, then becoming moderate to locally heavy mid-day. Moderate ridgeline W winds becoming SSE in the afternoon. Light east winds at Pass level.
Sunday
Night
Light to moderate rain and snow easing after midnight. Strong W ridgeline and Pass level winds easing after midnight.
Sunday
Light to moderate rain and snow near the Cascade crest this morning, easing late morning, then becoming moderate near the crest again late. Moderate ridgeline winds.
Sunday
Night
Light to moderate rain and snow, heaviest near the crest, becoming lighter after midnight. Strong ridgeline winds easing after midnight.
Sunday
Light to moderate rain and snow near the Cascade crest this morning, easing late morning, then becoming moderate near the crest again mid-day. Moderate ridgeline winds becoming strong in the afternoon.
Sunday
Night
Light to moderate rain and snow, heaviest near the crest, becoming lighter after midnight. Strong ridgeline winds.
Sunday
Light to moderate rain and snow near the Cascade crest this morning, easing late morning, then becoming moderate near the crest again mid-day. Moderate ridgeline winds becoming strong in the afternoon.
Sunday
Night
Light to moderate rain and snow, heaviest near the crest, becoming lighter after midnight. Strong ridgeline winds easing after midnight.
Sunday
Moderate to heavy rain and snow. Strong to extreme winds.
Sunday
Night
Moderate to heavy rain and snow becoming light showers after midnight. Strong to extreme ridgeline winds easing after midnight.
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).