MOUNTAIN WEATHER FORECAST

Stevens Pass Mountain Weather Forecast

Friday, February 28, 2020, 0900

Current Observations:

24hr Precipitation:        0

Temperature profile:     32 base, 36 ridge

Pass level winds:             light WSW

Barometer:                    1016mb’s and falling

Sky:                     clear with high cirrus clouds moving in

Radar:  dry throughout the region with the approaching cold front a few 100 miles offshore.

The Forecast:  Increasing clouds, falling temperatures and snow tonight.  Snow showers persist tomorrow with Sunday trending dry.

The Science:  Visible satellite images show a district shear line of clouds out a head of the approaching cold front tracking ENE.  The current temperature inversion will be quickly be overtaken by strong, cool, unstable westerly flow this afternoon.  The Puget Sound convergence zone is expected to develop with periods of moderate snow for Stevens Pass overnight.  The precipitation will transition to showers during the early morning hours with moderate passing snow showers through the day tomorrow.     

Long Range. Sunday will be mostly dry with sun breaks.  Several storms are poised to bring significant snow to the Cascades next week.  Early calculations show 40+ inches of snow possible starting on Monday and lasting through the week.   **  Winter isn’t done with us yet.

Confidence:  Fair due to orographic snow amounts.  

Values from 4am today through 4am tomorrow.

Precipitation: Today 24hr water:  .5-.75 snow:  6-10 (depending on convergence) Tomorrow’s 24hr water:  .5  snow: 3-6 Trend and Timing: Snow begins after 4pm today and becomes moderate overnight.  Snow shifts to showers after 4am tomorrow with intermittent showers through the day.

Temperature: Low: 26   High: 40 Freezing level: 6000’ – 2500’ Trend and Timing:    Freezing levels will peak +-6000’ this afternoon and then quickly fall below 4000’ tonight.  Temperatures will remain below freezing through Sunday.

Winds Base: 5-10 W increasing Ridge Top: 10-20+ W  strengthening Trend and Timing: Winds increase tonight and sustain through 10am or so tomorrow.