March arrived without much fanfare. Surface temperatures are a few degrees warmer than yesterday morning at most NWAC stations. The exception is where a shallow cold air pool has formed at low elevations along the east slopes of the Cascades and light E wind is moving that colder air through the mountain gaps. This may continue to create a weak inversion in the mountain gaps through mid-morning before enough solar radiation gets through to warm the lower atmosphere. Expect another mild day with freezing levels topping out in the 5000-6500 ft range across the region. Moderate ridgeline winds in the Mt. Baker area may ease slightly as winds shift from SSW to WSW during the day.
A weakening cold front approaching the nearshore waters should split in such a way that the Pacific Northwest gets very little precipitation by the time it arrives Monday night. Areas from Snoqualmie pass north to Mt. Baker might see a trace to an inch of snow above 3500-4000 ft as temperatures cool behind the front. The cooling will be more significant across northern and western Washington than further south, such as around Mt. Hood. Ridgeline winds should increase into the moderate range along the E slopes of the Cascades and Mt. Hood areas before decreasing into the light to moderate range on Tuesday.
Snow flurries linger Tuesday morning in the mountain loop and Mt. Baker areas ending early. Temperatures should be near seasonal norms on Tuesday for the mountains of Washington State and slightly above normal for Mt. Hood. Clouds should gradually decrease throughout the day from around Steven Pass southward, leading to increasing sunshine.
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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Monday
Mid and high-level clouds with periods of filtered sunshine.
Monday
Night
Partly cloudy.
Monday
Mid and high-level clouds with periods of filtered sunshine.
Monday
Night
Mostly cloudy with periods of very light rain or snow.
Monday
Mid and high-level clouds with periods of filtered sunshine.
Monday
Night
Mostly cloudy with periods of very light rain or snow.
Monday
Mid and high-level clouds with increasing periods of filtered or direct sunshine.
Monday
Night
Mostly cloudy.
Monday
Mid and high-level clouds with periods of filtered or direct sunshine late in the day. Light E wind switching W at the Pass late in the day.
Monday
Night
Mostly cloudy with a chance of very light rain or snow. Light W wind at the Pass.
Monday
Mid and high-level clouds with periods of filtered or direct sunshine late in the day. Light E wind switching W at the Pass late in the day.
Monday
Night
Mostly cloudy with a chance of very light rain or snow. Light to occasionally moderate W wind at the Pass.
Monday
Mid and high-level clouds with periods of filtered or direct sunshine late in the day.
Monday
Night
Partly cloudy with a slight chance of snow flurries.
Monday
Mid and high-level clouds with increasing periods of filtered or direct sunshine.
Monday
Night
Partly cloudy.
Monday
Mid and high-level clouds in the morning with increasing periods of filtered or direct sunshine in the afternoon.
Monday
Night
Partly cloudy.
Monday
Mid and high-level clouds early, then increasing periods of filtered or direct sunshine.
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).