Upper level ridging will traverse the Cascades today leading to a dry and mild day with light winds. A Pacific frontal system upstream over northern Vancouver Island will slowly sag southward today, spreading increasing high clouds over the northern half of the forecast area and leading to some filtered sunshine over the Olympics and north Cascasdes. Freezing levels will be on the rise today, peaking in the 6000-8000' range with mid-mountain maximum temperatures generally in the upper 30s to 40s.
We'll see mild temperatures and limited cooling Wednesday night as high clouds increase ahead of the approaching frontal system. Light rain and snow should begin over the Olympics and northwest Cascades in the morning and slowly spread southward during the day. The parent low center will pull south along the coastline, stalling the front's eastward progress Thursday. The south Cascades and Mt Hood area will see an increase in cloud cover but should remain dry. Snow/freezing levels will cool for areas closer to the frontal boundary in the afternoon. Moderate S-SW ridgeline winds will develop over the Olympics and the Mt Baker on Thursday as well.
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
Mostly sunny with periods of high clouds this morning, then partly sunny with high clouds and filtered sunshine in the afternoon.
Wednesday
Night
Overcast.
Wednesday
Mostly sunny with periods of high clouds this morning, then partly sunny with high clouds and filtered sunshine in the afternoon.
Wednesday
Night
Overcast.
Wednesday
Mostly sunny with periods of high clouds this morning, then partly sunny with high clouds and filtered sunshine in the afternoon.
Wednesday
Night
Overcast.
Wednesday
Mostly sunny. Occasional high clouds increasing in the afternoon.
Wednesday
Night
Mostly cloudy in the evening, becoming overcast after midnight.
Wednesday
Mostly sunny with a few high clouds this morning, then partly to mostly sunny with periods of high clouds and filtered sunshine in the afternoon. Light W ridgeline and Pass level winds.
Wednesday
Night
Mostly cloudy in the evening, becoming overcast after midnight. Light W ridgeline and Pass level winds.
Wednesday
Mostly sunny with a few high clouds this morning, then partly to mostly sunny with periods of high clouds and filtered sunshine in the afternoon. Light W ridgeline and Pass level winds.
Wednesday
Night
Mostly cloudy in the evening, becoming overcast after midnight. Light W ridgeline and Pass level winds.
Wednesday
Mostly sunny with a few high clouds this morning, then partly to mostly sunny with periods of high clouds and filtered sunshine in the afternoon.
Wednesday
Night
Overcast.
Wednesday
Mostly sunny with a few high clouds this morning, then partly to mostly sunny with periods of high clouds and filtered sunshine in the afternoon.
Wednesday
Night
Mostly cloudy in the evening, becoming overcast after midnight.
Wednesday
Mostly sunny. Occasional high clouds increasing in the afternoon.
Wednesday
Night
Partly cloudy in the evening, becoming mostly cloudy after midnight with increasing high clouds.
Wednesday
Mostly sunny. Occasional high clouds increasing in the afternoon.
Wednesday
Night
Partly cloudy in the evening, becoming mostly cloudy after midnight with increasing high clouds.
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).