Wow, that was a wild, wet night across the mountains! Most weather stations recorded 1-3 inches of water overnight!!! Temperatures continue to cool this morning with a few inches of snow accumulating at some trailheads. Washington Pass managed to stave off the warm weather and stack up 8 inches since yesterday evening.
Most locations will see a break in the action today as the thrust of the precipitation shifts south into Oregon. This morning, low clouds and a few showers could give way to moments of blue sky, particularly in the northern and eastern zones. Gusty wind along the east side of the range should also decrease. Clouds will start to thicken and lower this afternoon ahead of our next tidal wave of precipitation. The exception to today's 'break' will be Mt Hood and Mt Saint Helens. Down south, heavy rain, very gusty winds, and warm temperatures will maintain stormy conditions. Several hours of 1/4 to 1/3 inch of water per hour are likely.
This evening, another atmospheric river slams into the region. This one is just as wet as Monday's storm; the big difference is that it looks much longer and a notch warmer. Expect sustained very heavy precipitation rates (1/4"-1/3' per hour) near and west of the crest. Strong winds also carry moisture to the eastern zone, providing inches of water for most locations. Snow levels will quickly climb as rain begins to reach 7000-8500 ft overnight. Washington Pass and the East North zone will try to hang on to cold air and maintain snowfall. They probably will through the night, but by Wednesday, the flood of warm air should finally overtake the area and send snow levels climbing above the pass. The storm doesn't let up on Wednesday. Most locations continue to experience heavy rain and high elevation snow.
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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Tuesday
Light snow in the early morning, and tapering off. Cloudy. Cool temperatures, warming into the afternoon.
Tuesday
Night
Rain and mountain snow, with continual warming through the night.
Tuesday
Cloudy. Cool temperatures, warming in the afternoon.
Tuesday
Night
Rain and mountain snow, with continual warming through the night.
Tuesday
Light snow in the early morning, and tapering off. Cloudy. Cool temperatures, warming into the afternoon.
Tuesday
Night
Heavy rain and mountain snow. Warming temperatures through the night.
Tuesday
Snow in the early morning, tapering off quickly. Cloudy. Cool temperatures, warming into the afternoon.
Tuesday
Night
Heavy rain and mountain snow. Warming temperatures through the night.
Tuesday
Brief periods of rain and mountain snow, tapering off. Warming temperatures through the day. Light ridgeline wind, from the west at the Pass.
Tuesday
Night
Heavy rain and mountain snow. Warming temperatures through the night. Moderate ridgeline wind, becoming strong, from the west at the Pass.
Tuesday
Brief periods of rain and mountain snow, tapering off. Warming temperatures through the day. Light ridgeline wind, from the west at the Pass.
Tuesday
Night
Heavy rain and mountain snow. Warming temperatures through the night. Moderate ridgeline wind, becoming strong, from the west at the Pass.
Tuesday
Cloudy. Cool temperatures, warming slightly in the afternoon.
Tuesday
Night
Heavy rain and mountain snow. Warming temperatures.
Tuesday
Brief periods of isolated rain and mountain snow, becoming mostly cloudy in the afternoon.
Tuesday
Night
Heavy rain and mountain snow. Warming temperatures.
Tuesday
Brief periods of isolated rain and mountain snow, becoming mostly cloudy in the afternoon.
Tuesday
Night
Heavy rain and mountain snow. Warming temperatures.
Tuesday
Heavy rain. Strong westerly wind at ridgeline.
Tuesday
Night
Heavy rain and warming temperatures. Strong to extreme ridgeline wind from the WSW.
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).