MOUNTAIN WEATHER FORECAST

Stevens Pass Mountain Weather Forecast

Day and Time: Monday 0630

Current Observations:

24hr Precipitation: .18” w, 2” snow = SWE 9% 

Pass temperature: 33

Pass level winds:  +-5mph W

Barometer: slightly up to 1011mb’s  

Sky: OC

Radar: abundant scattered rain and snow showers to the west with evidence of a weak convergence zone in the Snohomish Valley.

The Forecast: Light mixed rain and snow showers this morning with moderate to heavy snow tonight.   Tomorrow will be sporty with high winds, heavy precipitation and fluctuating freezing levels.

Long Range: Wednesday will be an interim day with another warm system moving up the PNW coast on Thursday.  Friday and Saturday look fairly dry with another system expected on Sunday/Monday.  

  

The Science: A cold front, now moving through Eastern Washington, has left scattered showers and some unstable westerly flow in its wake.  A weak Puget Sound Convergence zone has formed which is the source of our current shower activity. 

The next triple point system will approach the region tonight. East flow is expected to redevelop which will help hold temperatures near freezing. 

The freezing levels are expected to briefly fall with the passing of cold front tonight.

Several gradient waves powered by strong WSW flow will kick in overnight with high winds likely to start the day.  Convergence zone orographics and freezing levels bouncing between 4000’ and 5000’ will be the battle tomorrow. 

 Confidence is fair with precipitation values.  Confidence in the timing of freezing levels and east flow influence is fair to low.

   

Values from 4am today through

 4am tomorrow.

Precipitation: Today 24hr water:.5-.75   snow: 4-6 base, 5-8 upper mountain Tomorrow’s 24hr water:.75-1   snow: 4-8 Trend and Timing: Moderate to heavy precipitation begins after 4pm today and continue through noon or so tomorrow.

Temperature: Low: 30    High: 34 Freezing level: 4500’ – 4000’ Trend and Timing:    Freezing level will fall to 3500’ tonight and then rise back up to +4500’ tomorrow.

Winds Base: 0-5 E Ridge Top: 5-15 S Trend and Timing: Surface east flow with southerly flow aloft will persist through at least midnight tonight.  Winds shift westerly and strengthen early tomorrow morning.