A weak cold front sweeps down from the northwest on Thursday bringing impactful winds, strongly cooling temperatures, and some very light snowfall. Temperatures are dropping quickly in advance of the late morning frontal passage with high clouds lowering early this morning. A weak convergence band formed early this morning in the Mt Baker area and should gradually shift southward as the day progresses, reaching central Cascade passes in the afternoon. Ridgeline W winds focus on areas near and east of the Cascade Crest, ramping up into the moderate to strong range from mid-morning through the afternoon. In the Mt Hood area, these winds peak in the afternoon through early evening hours and could be sustained in the strong range.
A few very light showers may linger between Snoqualmie and Crystal in the early evening hours before upper-level flow shifts more NNWerly and moisture cuts off. Once it does, expect clearing skies, but a cold day on Friday with freezing levels topping out around 3000 ft.
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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Thursday
Mostly cloudy with a slight chance of snow flurries.
Thursday
Night
Partly cloudy with clearing skies overnight.
Thursday
Periods of light rain or snow with chances increasing in the mid-day and afternoon hours. Moderate ridgeline winds.
Thursday
Night
Partly cloudy with gradually clearing skies.
Thursday
Periods of light rain or snow with chances increasing in the mid-day and afternoon hours. Moderate ridgeline winds.
Thursday
Night
Partly cloudy with gradually clearing skies.
Thursday
Periods of light rain or snow with chances increasing in the mid-day and afternoon hours. Moderate ridgeline winds may be strong at times near the Cascade Crest.
Thursday
Night
Partly cloudy with gradually clearing skies.
Thursday
Mostly cloudy in the morning. Periods of light rain or snow with chances increasing in the mid-day and afternoon hours. Moderate ridgeline winds at times. Light W wind at the Pass.
Thursday
Night
Mostly cloudy in the evening with an isolated snow flurry early, then gradual clearing. Decreasing light to occasionally moderate ridgeline winds. Light W wind at the Pass.
Thursday
Mostly cloudy in the morning. Periods of light rain or snow with chances increasing in the mid-day and afternoon hours. Moderate ridgeline winds at times. Light to moderate winds at the Pass.
Thursday
Night
Mostly cloudy in the evening with a few very light snow showers early, then gradual clearing. Moderate ridgeline winds become light. Light W wind at the Pass.
Thursday
Partly cloudy. Moderate to strong ridgeline winds.
Thursday
Night
Mostly clear. Decreasing light to moderate ridgeline winds.
Thursday
Partly cloudy with a few snow flurries near the Cascade Crest. Moderate to strong ridgeline winds.
Thursday
Night
Mostly clear. Decreasing light to moderate ridgeline winds.
Thursday
Partly cloudy. Moderate to strong ridgeline winds.
Thursday
Night
Mostly clear. Decreasing light to moderate ridgeline winds.
Thursday
Partly to mostly cloudy. Strong ridgeline winds with extreme gusts at times.
Thursday
Night
Partly cloudy with gradually clearing skies. Decreasing moderate ridgeline winds with strong gusts.
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).