The Pacific Northwest will be under the influence of a broad upper level trough today. The trough is positioned off our coast and will rotate up a few showers and clouds today from the south. Areas slightly closer to the trough's influence, from I-90 and southward to Mt Hood, may see more convective shower activity in the afternoon through early evening. Freezing levels will rise to around 4500', but expect snow levels to fall to 3500-4000' with precipitation.
As the broad upper level trough pushes in the southwestern US tonight, skies will clear from north to south, with cloudier conditions hanging on for Mt Hood through the night. Upper level ridging upstream over British Columbia will shift closer to our area on Thursday. While we'll have dry weather on Thursday, look for northerly winds to make for breezy conditions along ridgelines and higher peaks. Freezing levels will top out around 5000-5500'. We should also see some a few cumulus clouds pop up in the afternoon, particularly along the west slopes of the Cascades.
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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Wednesday
Partly sunny to mostly cloudy. Chance of light afternoon showers. Light ridgeline winds.
Wednesday
Night
Partly to mostly cloudy in the evening, then becoming mostly clear. Light ridgeline winds.
Wednesday
Partly sunny to mostly cloudy. Chance of light afternoon showers. Light ridgeline winds.
Wednesday
Night
Partly to mostly cloudy in the evening, then becoming mostly clear. Light ridgeline winds.
Wednesday
Partly sunny to mostly cloudy. Chance of light afternoon showers. Light ridgeline winds.
Wednesday
Night
Partly to mostly cloudy in the evening, then becoming mostly clear. Light ridgeline winds.
Partly to mostly cloudy in the evening, then becoming mostly clear. Light ridgeline winds.
Wednesday
Partly sunny to mostly cloudy. Chance of light afternoon showers. Light to occasionally moderate W ridgeline winds decreasing in the afternoon. Light Pass level winds.
Wednesday
Night
Partly to mostly cloudy in the evening, then becoming mostly clear. Light winds.
Wednesday
Partly sunny to mostly cloudy. Scattered light afternoon showers. Light to occasionally moderate W ridgeline winds decreasing in the afternoon. Light Pass level winds.
Wednesday
Night
Partly to mostly cloudy in the evening, then becoming mostly clear. Light winds.
Wednesday
Partly sunny to mostly cloudy. Chance of light afternoon showers. Light ridgeline winds.
Wednesday
Night
Partly to mostly cloudy in the evening, then becoming mostly clear. Light to occasionally moderate ridgeline winds.
Wednesday
Partly sunny to mostly cloudy. Light to occasionally moderate ridgeline winds decreasing in the afternoon.
Wednesday
Night
Partly to mostly cloudy in the evening, then becoming mostly clear. Light to occasionally moderate ridgeline winds.
Wednesday
Partly sunny to mostly cloudy. Scattered light afternoon showers. Light to occasionally moderate ridgeline winds decreasing in the afternoon.
Wednesday
Night
Partly to mostly cloudy in the evening, then becoming mostly clear. Light to occasionally moderate ridgeline winds.
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).