Dry northerly flow aloft continues with a ridge offshore drifting to the coast by the end of the weekend. This pattern brings mostly clear/sunny skies through mid-day Sunday, with high clouds arriving ahead of Monday's weak disturbance. The region continues to experience sharp temperature gradients in both the horizontal and the vertical. As light ridgeline winds shift WNW, milder sinking air influenced by the high pressure continues to push into the region at middle and upper elevations. This will gradually override the low-level cold air pool east of the Cascade Crest, reaching a maximum around 4500 ft. The backdoor cold frontal passage on Friday cleared out most of the low cloud and stratus, but patchy low cloud lingers in the Snoqualmie Pass corridor into the morning hours. In the southern Cascades, freezing levels rise to 6000-7500 ft Saturday afternoon through Sunday. The interplay of multiple freezing levels will be more complex in the central Cascades, while the northern Cascades should see freezing levels rise to 5000-6000 ft west of the Cascades, but remain at the valley bottom in the Methow Valley region.
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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Saturday
Sunny and milder. Temperature inversions in the morning hours.
Saturday
Night
Mostly clear. A few thin high clouds.
Saturday
Sunny and milder. Temperature inversions in the morning hours.
Saturday
Night
Mostly clear.
Saturday
Sunny and milder. Temperature inversions in the morning hours.
Saturday
Night
Mostly clear.
Saturday
Sunny and milder. Temperature inversions in the morning hours.
Saturday
Night
Mostly clear. Temperature inversions.
Saturday
Sunny and milder. Strong temperature inversions. Light ridgeline decoupled from light E wind at the Pass.
Saturday
Night
Mostly clear. Temperature inversions. Light ridgeline winds decoupled from light E winds at the Pass.
Saturday
Sunny and milder. Strong temperature inversions. Light ridgeline decoupled from decreasing light to moderate E wind at the Pass.
Saturday
Night
Mostly clear. Temperature inversions. Light ridgeline winds decoupled from light E winds at the Pass.
Saturday
Sunny and milder at middle and upper elevations. Strong temperature inversions.
Saturday
Night
Mostly clear. Temperature inversions.
Saturday
Sunny and milder at middle and upper elevations. Strong temperature inversions.
Saturday
Night
Mostly clear. Temperature inversions.
Saturday
Sunny and milder at middle and upper elevations. Strong temperature inversions.
Saturday
Night
Mostly clear. Temperature inversions.
Saturday
Sunny and milder at middle and upper elevations. Strong temperature inversions and slower to warm on the east side of Mt Hood.
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).