A low tracking toward Haida Gwaii extends a weak warm front along the west coast of Canada into our region. This feature continues to touch off some light snow shower activity. Snow levels dropped 1000-2000 ft relative to this time yesterday and we're not expecting much warming today so snow levels should remain below 3000 ft throughout the region. Moderate W winds continue to buffet the mountain gaps and east slopes, particularly in the southern Cascades and Mt Hood area, where they are locally strong. These winds should continue as the main event with the storm (cold front) pivots toward the coast. Expect a slight decrease in the periods of snowfall early Friday morning as the warm front exists, then a gradual increase in light snowfall for the mountains of Washington, with increasing WSW and SW winds wringing out some moderate snowfall for the Mt Baker and Mt Rainier by the afternoon.
Light to moderate snowfall continues to ramp up Friday evening with moderate to heavy snowfall expected throughout the region overnight. A cold front moves through around 4 AM on Saturday. SSW winds peak in the moderate to strong range for favored locations for Mt Baker in the early morning hours. Winds should decrease quickly early Saturday and turn westerly, then increase during the afternoon as a cold trough settles into the region. Moderate snow showers and locally heavy snowfall under a convergence band swinging southward through the central Washington Cascades decrease and become light in the afternoon as snow levels drop to around 2000 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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Friday
Light snow develops and increases in the afternoon. Light ridgeline winds become moderate.
Friday
Night
Moderate to heavy snow. Moderate ridgeline winds become light overnight.
Friday
Periods of light snow increase during the afternoon and become moderate late in the day. Increasing moderate ridgeline winds.
Friday
Night
Heavy snow. Moderate to strong ridgeline winds decrease overnight.
Friday
Periods of light snow increase during the afternoon and become moderate late in the day. 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).