MOUNTAIN WEATHER FORECAST

Stevens Pass Mountain Weather Forecast

Day and Time: Thursday 0630a

Current Observations:

24hr Precipitation:  lightly snowing, SWE-.16 with 1” of snow.

Temperature profile: 31

Pass level winds: 5-10 ESE

Barometer: 1009mb’s and rapidly falling 

Sky: OC

Radar:  Wide spread rain is entering the Puget Sound region and tracking NE.

The Forecast:  Mixed rain and snow today shifting to snow this evening; colder with snow showers tomorrow and Saturday. A high wind watch will go into effect tonight as well.

Long Range: The storm track will remain active with snow continuing through the weekend.  

  

The Science:  A tightly packed surface low with a distinct gradient wave is entering the region this morning.  Freezing levels, out ahead of the leading warm front, are reading 55-6000’.   This system is tracking NNE with a strong cold front and said gradient wave hot on its heels.  Surface east flow has developed which will temporarily help shelter the Pass from too much warming. 

Once the cold front charges through, freezing levels will quickly fall with unstable westerly flow filling in. Post frontal flow will be strong with 5000’ wind gusts in the +40mph range.   The Puget Sound Convergence Zone associated with the gradient wave could produce some nice orographic snow fall through the night.

Weak mid level ridging between storms will move through the region tomorrow.  Cold drier air with some clearing will be possible tomorrow afternoon.  Another frontal system arrives on Saturday and then again on Sunday with more snow in tow.

Values from 4am today through

 4am tomorrow.

Precipitation: Today 24hr water: .75+  snow: 4-6 base, 5-8+ upper mountain Tomorrow’s 24hr water: .25  snow: 2-4 Trend and Timing: Mixed rain and snow shifting to show after 4pm today.  Convergence showers will persist through the night.

Temperature: Low: 24    High: 36 Freezing level: 5000’ – 2000’ Trend and Timing:    Freezing levels will peak at or above 5000’ today and then quickly fall to 2000’ overnight.

Winds Base: 5-10 E shifting W Ridge Top: 5-15 ESE shifting W Trend and Timing: East flow will hold through noon or so today and then shift westerly.  Post frontal winds will strengthen with 40mph gust likely.