A few leftover showers remain in the north and central Cascades but otherwise we're waiting for the next Pacific frontal system to arrive later today. A baroclinic leaf signature can be seen on satellite this morning, indicating a rapidly deepening low-pressure system offshore. Precipitation will spread into the Olympics by late morning and Mt Hood by mid-day and spread north over the Cascades, reaching the Canadian border by mid-afternoon. The heaviest shot precipitation will come tonight as an occluded front passes through the region and a bit more southerly component to this storm will spread precipitation along both the west and east slopes of the Cascades. Colder continental air can't be found on the east side of the Cascades, so while snow levels should briefly fall to 3000' with the onset of precipitation this evening at Snoqualmie Pass, snow levels, in general, will hang around 3500' for much of today and tomorrow. The Mt Hood area and far southern Washington Cascades will see snow levels rise to 6500' as they are on the warmer side of this storm.
As the frontal boundary passes inland Wednesday night, the flow aloft will become northwest with onshore westerly flow at the surface. This should do well to wring out moisture all day long for the west slopes of the Cascades and Mt Hood. The heaviest precipitation totals will be from about the Mt Loop Highway and south. Snow will pile up above 3500-4000' in most areas.
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
Wednesday
Light rain and snow developing late morning.
Wednesday
Night
Light to occasionally moderate snow showers overnight.
Wednesday
Cloudy with isolated rain and snow showers this morning. Light rain and snow developing in the afternoon.
Wednesday
Night
Moderate to occasionally heavy rain and snow.
Wednesday
Cloudy with isolated rain and snow showers this morning. Light rain and snow developing in the afternoon.
Wednesday
Night
Moderate to occasionally heavy rain and snow.
Wednesday
Cloudy with isolated rain and snow showers this morning. Light rain and snow developing midday and increasing late.
Wednesday
Night
Moderate to locally heavy rain and snow at Paradise.
Wednesday
Cloudy with isolated rain and snow showers this morning. Light rain and snow developing midday. East winds at Pass level rising to moderate in the afternoon.
Wednesday
Night
Moderate rain and snow. Moderate east winds becoming west after midnight.
Wednesday
Cloudy with isolated rain and snow showers this morning. Light rain and snow developing midday. East winds at Pass level rising to moderate in the afternoon.
Wednesday
Night
Moderate rain and snow. Moderate east winds becoming west after midnight.
Wednesday
Cloudy with light rain and snow developing in the early afternoon.
Wednesday
Night
Light to moderate rain and snow.
Wednesday
Cloudy with light rain and snow developing in the early afternoon.
Wednesday
Night
Light to moderate rain and snow.
Wednesday
Cloudy with light rain and snow developing midday.
Wednesday
Night
Light to moderate rain and snow becoming showers after midnight.
Wednesday
Wednesday
Night
Moderate rain and snow becoming showers 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).