An offshore ridge will bring mostly dry and progressively warmer weather to our region on Thursday and Friday.
Weak onshore flow has kept some low-level moisture trapped below around 5000 ft in areas west of the Cascades early Thursday. This has spawned a few isolated snow flurries for the foothills of the Cascades. With daytime warming mixing up this cloud layer and the expanding ridge, the low-level moisture should give way to partly cloudy skies and fully dry conditions as the day progresses. Freezing levels will top out in the 4500 ft range near and west of the Cascade Crest and around 5000 ft further east. Light ridgeline winds will generally be out of the N.
Expect clear skies Thursday night, with temperatures remaining relatively steady.
Friday should be sunny and warm. Freezing levels rise to 6500-7000 ft in the afternoon as light ridgeline winds shift from N to SE.
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 sunny in the morning with lowland fog in some areas, then partly cloudy in the afternoon.
Thursday
Night
Mostly clear. Milder.
Thursday
Partly to mostly sunny.
Thursday
Night
Mostly clear. Milder.
Thursday
Mostly cloudy to start with isolated snow flurries. Becoming partly cloudy.
Thursday
Night
Mostly clear. Milder.
Thursday
Mostly cloudy to start with isolated snow flurries. Becoming partly cloudy.
Thursday
Night
Mostly clear. Milder.
Thursday
Partly cloudy. Light ridgeline and W wind at the Pass.
Thursday
Night
Mostly clear. Milder. Light ridgeline and W wind at the Pass.
Thursday
Mostly cloudy with isolated snow flurries in the morning. Becoming partly cloudy. Light ridgeline and W wind at the Pass.
Thursday
Night
Mostly clear. Milder. Light ridgeline and W wind at the Pass.
Thursday
Mostly cloudy to start, then becoming mostly sunny.
Thursday
Night
Mostly clear. Milder.
Thursday
Partly cloudy to mostly sunny.
Thursday
Night
Mostly clear. Milder.
Thursday
Partly cloudy to mostly sunny.
Thursday
Night
Mostly clear. Milder.
Thursday
Mostly cloudy to start with a few snow flurries (western part). Partly 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).