The Pacific Northwest sits under weak northerly flow aloft at the western edge of a broad trough over the western US. This weak troughing creates just enough instability for continued light showers on Wednesday. These showers will be more driven by low-level onshore flow. A weak convergence zone currently sits over the Hwy 2 corridor, but moisture barely reaches Stevens Pass. This feature is likely to either remain in the same general vicinity or shift slightly north into the Mountain Loop as the day progresses. In other areas, scattered to isolated rain and snow showers are rotating in from the NW. They could become slightly more convective and intense during the afternoon. Snow levels will be in the 3000-3500 ft range, with temperatures 5 degrees warmer east of the Cascades, where it should be generally dry.
Most shower activity tapers during the evening hours with partially clearing skies overnight as an offshore ridge begins to expand into our region.
The expanding ridge will increase sunshine on Thursday, with freezing levels rising to 4500-6000 ft by the afternoon.
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
Mostly cloudy with a few light snow showers, mainly in the afternoon.
Wednesday
Night
Gradually clearing skies.
Wednesday
Mostly cloudy with scattered light rain and snow showers.
Wednesday
Night
A few light snow showers in the evening, then a gradual clearing.
Wednesday
Mostly cloudy with light rain and snow showers and weak convergence lifting gradually northward.
Wednesday
Night
A few light snow showers in the evening, then a gradual clearing.
Wednesday
Mostly cloudy. Isolated light rain and snow showers.
Wednesday
Night
A few light snow showers in the evening, then a gradual clearing.
Wednesday
Mostly cloudy with light snow showers. Light ridgeline and W wind at the Pass.
Wednesday
Night
A few light snow showers in the evening, then a gradual clearing. Light ridgeline and W wind at the Pass.
Wednesday
Mostly cloudy with light snow showers. Light ridgeline and W wind at the Pass.
Wednesday
Night
A few light snow showers in the evening, then a gradual clearing. Mostly light ridgeline and light W wind at the Pass.
Wednesday
Mostly cloudy.
Wednesday
Night
Gradually clearing skies.
Wednesday
Partly cloudy.
Wednesday
Night
Gradually clearing skies.
Wednesday
Partly cloudy.
Wednesday
Night
Gradually clearing skies.
Wednesday
Moslty cloudy with isolated light snow showers.
Wednesday
Night
A few snow showers in the evening, then partly cloudy.
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).