Post-frontal showers and convergence bands piled on the new snow last night with variable distribution across our mountains. Areas near and west of the Cascade crest generally saw 5-8" of snow with local high marks of 12-16" for Paradise, Snoqualmie Pass (more at higher elevations) and Mt Hood. Snowfall amounts tapered off quickly further east of the Cascade crest. Mid and upper mountain temperatures plunged into the teens and even single digits Tuesday morning as a much cooler air mass moved in aloft.
The upper level low/trough associated with this snowy and showery weather will dip south today and set up shop over the Great Basin. At the same time, upper level ridging and drier weather will take hold offshore putting us in a transition zone. Leftover snow showers will linger longest down near Mt Hood with occasional flurries near and west of the Cascade crest this morning. A general clearing trend will take place this afternoon. A few low clouds should hang around near and west of the Cascade crest. While winds are lighter than they were last night, you can expect the occasional brisk N-NW breeze along ridgelines today.
Tuesday night should start clear and cold. Occasional high clouds from a weak warm front well offshore will begin to stream over the north and central Cascades after midnight. On Wednesday we can expect increasing high clouds that will thicken in the afternoon mainly over the Olympics and north Cascades.
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
Partly to mostly cloudy in the morning with a few flurries, then mostly sunny.
Tuesday
Night
Mostly clear in the evening, then becoming partly cloudy with increasing high clouds after midnight.
Tuesday
Partly to mostly cloudy in the morning with a few flurries, then mostly sunny.
Tuesday
Night
Mostly clear in the evening, then becoming partly cloudy with increasing high clouds after midnight.
Tuesday
Cloudy with occasional flurries this morning then partly sunny in the afternoon. Occasional moderate ridgeline winds this morning.
Tuesday
Night
Mostly clear in the evening, then becoming partly cloudy with increasing high clouds after midnight.
Tuesday
Mostly cloudy with occasional flurries this morning then partly to mostly sunny in the afternoon. Occasional moderate ridgeline winds this morning.
Tuesday
Night
Mostly clear. A few high clouds after midnight.
Tuesday
Mostly cloudy with occasional flurries this morning then partly to mostly sunny in the afternoon. Light to moderate W-NW ridgeline and Pass level winds.
Tuesday
Night
Mostly clear in the evening, then becoming partly cloudy with increasing high clouds after midnight. Light to moderate W-NW ridgeline and Pass level winds.
Tuesday
Mostly cloudy with occasional flurries this morning then partly to mostly sunny in the afternoon. Moderate W-NW ridgeline and Pass level winds.
Tuesday
Night
Mostly clear in the evening, then becoming partly cloudy with increasing high clouds after midnight. Light to moderate W-NW ridgeline and Pass level winds.
Tuesday
Partly cloudy in the morning with a few flurries near the Cascade crest, then mostly sunny. Moderate ridgeline winds at times.
Tuesday
Night
Mostly clear in the evening, then becoming partly cloudy with increasing high clouds after midnight.
Tuesday
Partly cloudy in the morning with a few flurries near the Cascade crest, then mostly sunny. Occasional moderate ridgeline winds this morning.
Tuesday
Night
Mostly clear in the evening, then becoming partly cloudy with increasing high clouds after midnight.
Tuesday
Partly cloudy in the morning with a few flurries near the Cascade crest, then mostly sunny. Moderate ridgeline winds at times.
Tuesday
Night
Mostly clear. A few high clouds after midnight.
Tuesday
Mostly cloudy with light snow showers, mainly west side of the mountain. Partly to mostly sunny in the afternoon. Moderate ridgeline winds mainly this morning.
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).