A wet system continues to impact the region on Thursday. A warm front lifted north of the Canadian Border Wednesday night with a well-defined cold front moving across the Puget Sound area at 7 AM Thursday morning. The front should pass the Cascades by around 9 AM. Heavy rain ahead of the cold front should decrease behind the front as rain/snow, snow showers, and convergence develop. Temperatures should also drop significantly behind the front. Models continue to indicate a high likelihood that convergence will set up around Stevens Pass during the afternoon hours with up to 6" of snow possible with 1-2" per hour rates. Other areas may see some enhanced snowfall during the evening hours as subtle shortwave results in a brief period of more widespread light to moderate rain snow and a southward shift of the convergence toward Snoqualmie Pass. Snow levels should drop to Snoqualmie Pass level around dusk.
NW flow begins to dry the region out as snow showers taper later Thursday night. Friday should be dry with a cool-ish start with an inversion forming as a ridge of high pressure begins to build into the region. Temperatures warm significantly across the region in the afternoon. Temperatures will be above normal for January across the region.
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
Decreasing light rain showers gradually changing to snow showers with a period of enhanced rain/snow possible late in the day.
Thursday
Night
Light rain and snow showers possible during the evening, then becoming partly cloudy.
Thursday
Heavy rain and snow tapering to showers by the afternoon. Strong ridgeline wind gusts.
Thursday
Night
Light rain and snow showers ending by midnight. Becoming mostly cloudhy.
Thursday
Heavy rain and high elevation snow tapering to light to moderate showers and convergence by the afternoon as snow levels lower. Strong ridgeline wind gusts.
Thursday
Night
Light to moderate rain/snow and convergence during the evening, then tapering light snow showers overnight.
Thursday
Heavy (Paradise), moderate (White Pass), and light (Crystal) rain and snow in the morning with tapering showers in the afternoon. Strong ridgeline winds at times.
Thursday
Night
Decreasing light rain and snow showers.
Thursday
Heavy rain and high elevation snow tapering to light to moderate showers and convergence by the afternoon as snow levels lower. Strong ridgeline wind gusts.
Thursday
Night
Light to moderate rain/snow and convergence during the evening, then tapering light snow showers overnight.
Thursday
Heavy rain and high elevation snow tapering to light to occasionally moderate showers by the afternoon as snow levels lower. Strong ridgeline wind gusts.
Thursday
Night
Light to moderate rain/snow and convergence during the evening, then tapering light snow showers overnight.
Thursday
Moderate rain and snow in the morning tapering to light showers by the afternoon.
Thursday
Night
Mostly cloudy.
Thursday
Moderate rain and high elevation snow in the morning tapering to light showers. Freezing rain may linger in colder valleys during the morning hours. Strong ridgeline winds.
Thursday
Night
Light rain/snow and convergence spillover mainly near the Cascade Crest. Strong ridgeline winds through the evening hours.
Thursday
Light to moderate rain and high elevation snow peaking during the morning, then tapering to showers. Moderate to strong ridgeline winds.
Thursday
Night
Very light snow showers in the early evening giving way to mostly cloudy skies.
Thursday
Heavy rain and high elevation snow tapering to light to moderate as snow levels lower in the afternoon. Moderate to strong ridgeline winds.
Thursday
Night
Decreasing light rain and snow showers. Strong ridgeline wind gusts in the evening.
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).