MOUNTAIN WEATHER FORECAST

  

Stevens Pass Mountain Weather Forecast

Monday, November 18, 2019, 0800am

Current Observations:

24hr Precipitation:      .55” of rain, 0 inch of snow

Temperature profile:    35 base. 35 ridge

Pass level winds:          Calm,  westerly

Barometer:                 1016mb’s and falling

Sky:                             High clouds

Radar:  Light rain falling over the east slopes of the I-90 corridor with the norther portion of the state dry.  The incoming offshore moisture is begin to show up on radar as well.

The Forecast:  Rain this afternoon turning to snow tonight.  A drying trend begins tomorrow.

Long Range:  Wednesday through Friday will be cold, clear and dry.  

  

The Science:  A low pressure system, with a triple point at its core, will bring moderate snow to the Pass tonight.  Pressure gradients will tighten along the crest developing east flow.  Regional freezing levels are still fairly high due to the SW flow aloft.  But, cooler air will be pulled in from the north as this storm passes through the region.  Models have the center of the low tracking directly over the state with a trailing cold front ending the show tomorrow morning.

A high pressure ridge will take over with cold NE flow wrapping around the exiting low pressure system.  This will produce dry, cold and clear weather for the remainder of the week.

In the long range outlook, (the weekend) the northern jet stream develops a NW flow pattern.  This has the potential for the season’s first significant snow event… Caveat; this is a looooong ways out, but worth keeping an eye on.

Confidence:  Good.

Values from 4am today through 4am tomorrow.

Precipitation: Today 24hr water:.5-.75  snow: 3-5 Tomorrow’s 24hr water: .25   snow: 1.2 Trend and Timing: The moisture will likely start out as rain or rain snow mix this afternoon but then turn to snow tonight.

Temperature: Low: 28   High: 42 Freezing level: 7000’ - 4000’ Trend and Timing:    Freezing levels will begin to fall through the day with early morning lows in the upper 20’s.

Winds Base: 0-5 E shifting W tomorrow Ridge Top: 0-10 E shifting W tomorrow Trend and Timing: Weak easterly flow will develop today.  Winds shift back to westerly tomorrow.

jM