Brrr, it's another cold late March morning with mountain temperatures in the teens to 20s. We'll see a fair bit of cloud cover this morning with low clouds on the west slopes of the Cascades and Olympics and mid-level clouds along the east slopes of the Cascades mix with sunbreaks later this morning and mid-day. With the same cold upper trough overhead, we can expect increasing clouds to build up over the mountains and isolated showers in the afternoon through early evening hours. The Olympics will be a bit cooler, cloudier, with more scattered showers closer to a weak upper level area of low pressure.
After isolated to scattered snow showers wind down Sunday evening, we'll see a clearing trend begin overnight. However, mid-level cloud will begin to rotate inland over the Olymipcs, southern Washington Cascades and Mt Hood before daybreak Monday.
An upper low dropping south along the coastline on Monday will rotate high clouds as far north as Snoqualmie Pass on Monday. As you travel closer to the Canadian border, mostly sunny skies are more likely. We'll see temperatures and freezing levels bump up a notch on Monday. The biggest wind impact from the low pressure system spinning offshore will be increasing E-SE ridgeline and Pass level winds. Areas like Mt Hood, White Pass/Crystal Mt and Snoqualmie Pass will see strong winds in the afternoon. Winds will increase further Monday night.
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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Sunday
Partly to mostly cloudy this morning, then mostly cloudy with scattered light snow showers in the afternoon.
Sunday
Night
Mostly cloudy with scattered light snow showers in the early evening, then partly cloudy.
Sunday
Partly to mostly cloudy this morning, then mostly cloudy with isolated light snow showers in the afternoon.
Sunday
Night
Mostly cloudy with scattered light snow showers in the early evening, then mostly clear.
Sunday
Partly to mostly cloudy this morning, then mostly cloudy with isolated light snow showers in the afternoon.
Sunday
Night
Mostly cloudy with scattered light snow showers in the early evening, then mostly clear.
Sunday
Partly to mostly cloudy this morning, then mostly cloudy with isolated light snow showers in the afternoon. Showers may occasionally be moderate Mt Rainier and Mt St Helens area.
Sunday
Night
Mostly cloudy with scattered light snow showers in the early evening, then partly cloudy.
Sunday
Mostly cloudy with a few sunbreaks late morning or mid-day and isolated snow showers in the afternoon. Light to moderate W ridgeline and Pass level winds becoming lighter in the afternoon.
Sunday
Night
Mostly cloudy with scattered light snow showers in the early evening, then mostly clear. Light W winds at Pass level and ridgeline becoming light E after midnight.
Sunday
Mostly cloudy with a few sunbreaks late morning or mid-day and isolated snow showers in the afternoon. Light to moderate W ridgeline and Pass level winds becoming lighter in the afternoon.
Sunday
Night
Mostly cloudy with scattered light snow showers in the early evening, then partly cloudy. Light W winds at Pass level and ridgeline becoming light E after midnight.
Sunday
Partly to mostly cloudy this morning, then mostly cloudy with isolated light snow showers in the afternoon.
Sunday
Night
Partly cloudy with a few isolated snow showers, then mostly clear.
Sunday
Partly sunny this morning, then mostly cloudy with isolated light snow showers in the afternoon. Periods of moderate ridgeline winds this morning.
Sunday
Night
Partly cloudy with a few isolated snow showers, then mostly clear.
Sunday
Partly sunny this morning, then mostly cloudy with isolated light snow showers in the afternoon. Periods of moderate ridgeline winds this morning.
Sunday
Night
Partly cloudy with a few isolated snow showers, then mostly clear.
Sunday
Partly sunny this morning, then mostly cloudy with isolated light snow showers in the afternoon. More showers and clouds west side of the mountain. Moderate ridgeline winds this morning.
Sunday
Night
Partly cloudy. A few isolated snow showers 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).