The Pacific Northwest squeezes in a mostly dry day as a weak ridge wedge into the region. Light WSW winds at mid-levels continue to filter mild air to locations near and west of the Cascade Crest, with many locations near 5000 ft in the 30s for the Central Washington Cascades southward on Thursday morning. East of the Cascades, cold air remains entrenched and with warm air putting a lid air movement, deep valley locations such as Mazama has been in the ice box (below zero). This has created a 30+ degree inversion at Washington Pass. The inversion is less significant at Snoqualmie Pass and should mix out with daytime warming, bringing above freezing temperatures to most elevations by the afternoon. Skies should be partly to mostly cloudy across the region with some very light rain or snow showers arriving across the northern and western Cascades late in the day.
A compact, but deep low dropping down the west coast of Canada spreads a band of increasing warm frontal precipitation into the region Tuesday night. The heaviest rain and snow should focus on the mountain loop and Mt. Baker areas. Mt. Baker can expect 8-12" of dense snowfall by Wednesday morning. WSW ridgeline winds should increase overnight, becoming strong in some locations east of the Cascade Crest and at Mt. Hood overnight.
Flow switches SW and then SSW on Wednesday within the warm sector of the storm. The strongest winds are likely to focus on the Olympics and Mt. Bake with the heaviest rain and snow on the volcanoes - locations such as Paradise and Mt. Baker. Snow levels should be slightly lower - in the 3500 ft range.
Weather Forecast
Olympics
West North
West Central
West South
Stevens Pass
Snoqualmie Pass
East North
East Central
East South
Mt. Hood
Use dropdown to select your zone
Tuesday
Partly cloudy in the morning, then becoming mostly cloudy with a slight chance of a rain or snow shower in the afternoon. Mild.
Tuesday
Night
Increasing light rain and snow, becoming showery by morning.
Tuesday
Partly cloudy early, then becoming mostly cloudy with increasing chances of snow showers.
Tuesday
Night
Heavy rain and snow.
Tuesday
Partly cloudy early, then becoming mostly cloudy with increasing chances of rain or snow showers in the afternoon. Mild.
Tuesday
Night
Heavy rain and snow.
Tuesday
Partly to mostly cloudy. Mild.
Tuesday
Night
Rain and snow: Becoming heavy at Paradise, moderate at White Pass, and light at Crystal.
Tuesday
Partly cloudy early, then becoming mostly cloudy with increasing chances of rain or snow showers in the afternoon. Mild. Decreasing light E winds at the Pass.
Tuesday
Night
Light rain and snow becoming moderate. Light E wind switching W and increasing into the moderate range at the Pass.
Tuesday
Partly cloudy early, then becoming mostly cloudy with a slight chance of a rain or snow shower in the afternoon. Mild. Decreasing light E winds at the Pass.
Tuesday
Night
Light rain and snow above pass level, becoming moderate. Light E wind switching W and increasing into the moderate range at the Pass.
Tuesday
Partly cloudy with a strong inversion in the morning making temperatures very cold in the valleys. Then becoming mostly cloudy with a chance of very light snow showers in the afternoon.
Tuesday
Night
Light snow becoming moderate.
Tuesday
Partly cloudy with increasing clouds. Milder western part after inversion mixes out.
Tuesday
Night
Light snow developing and becoming moderate western part. Increasing ridgeline winds becoming moderate to strong overnight.
Tuesday
Partly cloudy. Mild after inversion mixes out.
Tuesday
Night
Increasing light rain and snow.
Tuesday
Partly cloudy; clouds increasing during the afternoon. Mild.
Tuesday
Night
Light rain and snow becoming moderate overnight and cooling. Increasing ridgeline winds becoming strong overnight.
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).