Mountain Weather Forecast

Stevens Pass Mountain Weather Forecast

Day and Time: Saturday 0630

Current Observations:

24hr Precipitation:   .6” (5” snow on upper mountain, turned to rain after midnight)

Pass temperature:  38 base, 35 upper mountain

Pass level winds:   Strong and gusty from the west/southwest

Barometer:  Dropped to 1015

Sky:   Overcast/raining

Radar:  Showers over the Cascades and Olympics, relatively dry in the Puget Sound at the moment

The Forecast: Rain showers and windy during the day Saturday. Mixed precip Saturday afternoon turning to all snow Saturday evening and night with continued strong and gusty winds. Light snow showers and cool on Sunday.

Long Range:  An upper level ridge begins nudging in on Sunday afternoon, turning flow northerly and bringing a dry and cool end to 2018. Monday and Tuesday should be calm with freezing levels in the 2000’ range and partly cloudy. The next active weather period arrives Wednesday night with a warm front.

  

The Science: The warm up and switch to rain has arrived as advertised. With no east flow in place, the advection of warm air turned the precipitation to rain overnight. Rain showers should continue during the day Saturday with strong, gusty winds as the associated cold front approaches. Frontal passage looks to occur Saturday afternoon, most likely bringing a burst of moisture and more gusty winds. Behind the front, cold air sinks in over the PNW in northwesterly flow aloft. This favorable wind direction should drive orographic showers throughout the night on Saturday. A convergence zone will likely set up, but currently looks to be a bit to the south of Stevens Pass. As high pressure builds on Sunday, drier and cooler air will slide down the ridge bringing a cool day and tapering light snow showers.

Values from 4am today through

 4am tomorrow.

Precipitation: Today 24hr water:  1.0”   snow: 6-8” Tomorrow’s 24hr water:  LT .25  snow: 1-3” Trend and Timing: Rain turning to mixed precip Saturday afternoon, all snow after 4pm and overnight.

Temperature: Low: 25    High: 38 Snow level: 5500’-2500’ Trend and Timing:    Snow level should lower in the afternoon, becoming all snow after 4pm.

Winds Base: 15-25 W Ridge Top: 35-45 SW/W, with stronger gusts Trend and Timing: Strong southwest winds should continue Saturday morning, with a slight lull in the afternoon before increasing again Saturday night.