The upper low impacting our region moved into the Columbia Basin early Thursday morning. Snow shower activity lingers in the wake of the low, as moderate W ridgeline winds focus it on the W slopes of the Cascades. A convergence brings moderate snowfall rates to the mountain loop and Stevens Pass, with a chance for it to shift south towards Snoqualmie Pass. Expect some spillover to the east of the Cascade Crest with this band. In most other areas, snow shower activity will be light with a general decreasing trend. Ridgeline winds may actually increase through the morning hours, focusing moderate winds on areas near and east of the Cascade Crest, particularly in the central and southern Cascades. Snow levels hover around 2500 ft in the morning, bumping up to 3500 ft in the afternoon.
Snow showers mostly taper off during the evening, with a few lingering snow showers over the northern Cascades as a ridge builds into the region Thursday night. This initiates a subtle warming trend.
With clearing skies, Friday morning starts chilly, but the expanding ridge of high pressure brings strong warming during the day. Freezing levels start out around 3000 ft, but reach 4500 ft in the north and 7500 ft near Mt Hood by the evening. Expect mostly sunny skies in the central and southern Cascades, but mostly cloudy conditions in the Mt Baker area with a slight chance of rain or snow showers as a system skirts to our north.
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
Thursday
Mostly cloudy with light snow showers mostly ending in the morning hours.
Thursday
Night
Mostly cloudy.
Thursday
Scattered light snow showers.
Thursday
Night
Mostly cloudy with a few very light snow showers.
Thursday
Moderate snow showers enhanced by convergence in the morning, becoming light in the afternoon.
Thursday
Night
Decreasing light snow showers.
Thursday
Decreasing mostly light snow showers.
Thursday
Night
Light snow showers ending in the evening hours.
Thursday
Decreasing light snow showers (moderate in convergence banding during the morning hours). Increasing light to occasionally moderate ridgeline and W wind at the pass.
Thursday
Night
Decreasing light snow showers end overnight. Decreasing mostly light ridgeline and W wind at the Pass.
Thursday
Decreasing light snow showers (moderate in convergence banding during the morning hours). Increasing light to occasionally moderate ridgeline and W wind at the pass.
Thursday
Night
Decreasing light snow showers end overnight. Decreasing light to moderate ridgeline and W wind at the Pass.
Thursday
Decreasing light snow showers with sun breaks. Moderate ridgeline winds.
Thursday
Night
Partly cloudy.
Thursday
Decreasing light snow showers near the Cascade Crest with increasing sunshine further east. Moderate ridgeline winds.
Thursday
Night
Partly cloudy.
Thursday
Decreasing light snow showers near the Cascade Crest with increasing sunshine further east. Moderate ridgeline winds.
Thursday
Night
Partly cloudy.
Thursday
Decreasing light to moderate snow showers. Moderate ridgeline winds may become strong at times.
Thursday
Night
Light snow showers ending in the evening hours. Decreasing moderate ridgeline winds become light.
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).