An upper level low dropping south toward California continues to float mid and high clouds over the central and south Washington Cascades this morning with a quick transition to mostly clear skies closer to the Canadian border. Light easterly flow is combining with the weak lift associated with the upper low to squeeze out a few snow flurries for the Cascade Passes and south Washington Cascades. Cloud cover will give way to mostly sunny skies today as the upper low becomes an open trough and shifts inland over the Great Basin. Cloudier skies are likely to linger longest for the Mt Hood area closest to the upper level low.
We'll have cool northerly flow aloft over us tonight with light winds. While we can't rule out areas of valley fog, generally clear conditions are expected over the region. Cool temperatures and sunny skies will hold for all areas on Saturday as we wait for a weak Pacific frontal system to approach from the Northwest. The frontal system will arrive late Saturday night and Sunday.
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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Friday
Mostly cloudy early then becoming mostly sunny late morning.
Friday
Night
Mostly clear.
Friday
Mostly sunny.
Friday
Night
Mostly clear.
Friday
Partly to mostly cloudy early then becoming mostly sunny late morning.
Friday
Night
Mostly clear.
Friday
Cloudy in the morning with occasional snow flurries, then becoming mostly sunny mid-day.
Friday
Night
Mostly clear.
Friday
Cloudy in the morning with occasional snow flurries, then becoming mostly sunny mid-day.
Friday
Night
Mostly clear. Light and variable winds at Pass level.
Friday
Cloudy in the morning with occasional snow flurries, then becoming mostly sunny mid-day.
Friday
Night
Mostly clear. Light and variable winds at Pass level.
Friday
Mostly sunny.
Friday
Night
Mostly clear.
Friday
Mostly cloudy early then becoming mostly sunny late morning.
Friday
Night
Mostly clear.
Friday
Cloudy early then becoming mostly sunny late morning.
Friday
Night
Mostly clear.
Friday
Cloudy in the morning with occasional snow flurries, becoming mostly cloudy in the afternoon.
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).