A persistent high pressure parked offshore continues to dominate the weather in our region. A closed low parked over southern California completes the blocking pattern that will fend off storm track through the first half of the work week.
The Pacific Northwest can expect light northerly winds aloft, sunny/clear skies, and 10500-11000 ft freezing levels. With the high pressure providing subsidence and minimal wind to mix the atmosphere, continue to expect a stratified atmosphere with cold air pooling below 5000 ft east of the Cascade Crest and light to moderate E winds ushering that cold air through the mountain gaps. Cold air pools will be more limited to valley locations east of the Cascade Crest. Expect these inversions to mix out by late morning in most areas, but Washington Pass and areas well east of the Cascade Crest may not warm up.
Further west, cold air pooling will be more limited to valley areas. Places like Mt Baker, Paradise, and Hurricane Ridge stayed above freezing Sunday night and won't look back over the next few days. This stands in stark contrast to Mazama where the temperature is 0F at 6AM this morning. However, Washington Pass base is 20F and Washington Pass Upper is 36F; so if you want to thaw out, you'll just need to ascend out of the cold pool!
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
Sunny and mild. By late morning, inversions and a few clouds mix out along the north slope of the range.
Monday
Night
Clear and mild. Inversions re-develop, creating a secondary freezing level below around 4500 ft.
Monday
Sunny and mild. Inversions mostly mix out by late morning.
Monday
Night
Clear and mild. Inversions re-develop, creating a secondary freezing level below around 4500 ft.
Monday
Sunny and mild. Inversions mostly mix out by late morning.
Monday
Night
Clear and mild. Inversions re-develop, creating a secondary freezing level below around 4500 ft.
Monday
Sunny and mild. Inversions mostly mix out by late morning.
Monday
Night
Clear and mild. Inversions re-develop, creating a secondary freezing level below around 4500 ft.
Monday
Sunny and mild. Inversions mostly mix out by late morning. Light ridgeline and E winds at the Pass.
Monday
Night
Clear and mild. Inversions re-develop, creating a secondary freezing level below around 5000 ft. Light ridgeline and light to moderate E winds at the Pass.
Monday
Sunny and mild. Inversions mostly mix out by late morning. Light ridgeline and light to moderate E winds at the Pass.
Monday
Night
Clear and mild. Inversions re-develop, creating a secondary freezing level below around 5000 ft. Light ridgeline and light to moderate E winds at the Pass.
Monday
Sunny and mild. Inversions mostly mix out by late morning.
Monday
Night
Clear and mild. Inversions re-develop, creating a secondary freezing level below around 5000 ft.
Monday
Sunny and mild. Inversions mostly mix out by late morning.
Monday
Night
Clear and mild. Inversions re-develop, creating a secondary freezing level below around 5000 ft.
Monday
Sunny and mild. Inversions mostly mix out by late morning.
Monday
Night
Clear and mild. Inversions re-develop, creating a secondary freezing level below around 5000 ft.
Monday
Sunny and mild. Inversions mostly mix out by late morning.
Monday
Night
Clear and mild. Inversions re-develop, creating a secondary freezing level below around 5000 ft.
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).