Mountain Weather Forecast

Stevens Pass Mountain Weather Forecast

Date: Sunday, December 1, 2019

Current Observations

24hr Precipitation:  0”

Temperature profile:    21 base / 14 on ridgetops

Pass level winds:   Light, easterly

Barometer:  1011 mb’s steady

Sky:  Cloudy

Radar:  Showers across the PNW, heaviest west of the crest, spotty in the mountains.

The Forecast: Cloudy with light snow flurries and cold temperatures today. Gradual warming overnight, mostly dry and cloudy Monday.

  

The Science: A double barrel low (two independent low pressure centers near each other) off the OR/CA coast is driving southerly flow aloft across Oregon and Washington. Wrap around moisture moving east across WA state is producing light snow across the Columbia Basin. In southerly flow aloft, Stevens Pass typically gets blocked by the Cascade Crest and that appears to be the case today. A few spotty snow flurries are possible this afternoon. As the two low pressure centers phase into a single cyclone and move a bit south, we will lose the easterly pass winds Sunday night. With that change, warmer Pacific air will advect into our region for a milder day Monday with the warmest temps we’ve seen in the past week.

Long Range:  The next system of interest arrives Tuesday night in SW flow aloft. Freezing levels are in question for this one, mixed precip type seems likely at Pass level. Active weather is in store for the rest of the week, temperatures look a little warm for our liking until the weekend.

Confidence: Poor for precip type after tomorrow.

Values from 4am today through 4am tomorrow.

Precipitation: Today 24hr water: .10   snow: 1-2” Tomorrow’s 24hr water: LT .10    snow: Trace Trend and Timing: Light snow most likely Sunday afternoon, ending Sunday night. Monday looks mostly dry.

Temperature: Low: 14   High: 28 Freezing level: 1000’ – 3500’ Trend and Timing:    Gradual warming Sunday afternoon, not as cold overnight as recent days.

Winds Base: 5-10 E, then W Ridge Top: 5-15 E, then WSW Trend and Timing: Winds light to moderate thru Monday morning, switching to westerly late Sunday afternoon.