The Pacific Northwest remains within a split flow pattern early Wednesday. Circulation around a cutoff low targeting California continues to bring some light to locally moderate ridgeline winds near the Cascade Crest from Snoqualmie Pass southward. These lower atmosphere winds continue to decrease as the cutoff low weakens and shifts southward, opening the door to weak northerly flow aloft as a subtle tongue of ridging moves into the area. The ridge will allow freezing levels to rise to around 6000 for most areas late Wednesday into the evening hours. A shift to light W winds as the trough axis shifts southwards helps the milder air move into lower elevations east of the Cascade Crest on Thursday.
Areas further west should begin to cool as a trough and frontal system approach the region from the NW, lowering freezing levels slightly for areas west of the Cascade Crest on Thursday. Expect periods of high clouds to move in, but low clouds generally remain offshore until Thursday night. WSW ridgeline winds generally increase as the day progresses, but remain light.
Weather Forecast
Olympics
West North
West Central
West South
Stevens Pass
Snoqualmie Pass
East North
East Central
East South
Mt. Hood
Use dropdown to select your zone
Wednesday
Sunny and mild.
Wednesday
Night
Clear skies.
Wednesday
Sunny and mild.
Wednesday
Night
Clear skies.
Wednesday
Sunny and mild.
Wednesday
Night
Clear skies.
Wednesday
Sunny and mild. Moderate wind gusts near the Cascade Crest through the morning hours.
Wednesday
Night
Clear skies.
Wednesday
Sunny. Light ridgeline and E wind at the Pass.
Wednesday
Night
Clear skies. Light ridgeline winds. Light E winds at the Pass switch to W in the early morning hours.
Wednesday
Sunny. Decreasing light to moderate ridgeline and mostly light E wind at the Pass.
Wednesday
Night
Clear skies. Light ridgeline winds. Light E winds at the Pass switch to W in the early morning hours.
Wednesday
Sunny. Strong inversions, particularly in the morning hours.
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).