MOUNTAIN WEATHER FORECAST

Stevens Pass Mountain Weather Forecast

Day and Time: Thursday 0700

Current Observations:

24hr Precipitation: 0 

Pass temperature: 16

Pass level winds: 5-15 E

Barometer: 1018mb’s and slowly falling

Sky:  Clear

Radar:  Clear

The Forecast:  This cold and clear weather will give way to increasing clouds and warming temperatures tomorrow.  Snow begins to fall in the Mountains early Saturday morning with an inch or two possible.  Another system arrives on Sunday with snow showers persisting into Monday.  Temperatures and freezing levels will slowly rise through this period but should remain below freezing with the aid of east flow.  

          Snow totals by 4am Monday morning will be in the 4-8” range.     

Long Range: Another strong winter storm is gearing up to hit the PNW on Tuesday and then again on Thursday.  Snow totals by the end of the week could exceed 24”.    

  

The Science:  The dropping barometer and the increased east/west pressure gradients along the Cascade Crest are the indicators of the developing low pressure system.   This is a large system with the center of the low stationed in the northern region of the Gulf of Alaska and the southern trough reaching into the warm water of California.

Warm air advection will begin to move up the western slopes over the next 24hrs.  Freezing levels west of the crest will climb to 4500’ with the eastern FL’s sticking around 2500’.  The game will be how the warm air to the west mixes with the cold air in the eastern basin.  Hopefully, the pass level east flow will hold strong and insulate Stevens Pass from the higher freezing levels through the weekend. 

The associated moisture will start out fairly weak and increase as frontal bands form within.  There are no distinct fronts (warm/cold) formed yet so stay tuned as those details materialize.  Game on.

   

Values from 4am today through

 4am tomorrow.

Precipitation: Today 24hr water: 0  snow: 0 Tomorrow’s 24hr water:<.10   snow: trace Trend and Timing: Dry through early Saturday morning.

Temperature: Low: 16    High: 22 Freezing level: 500’-2000’ Trend and Timing:    Freezing levels will begin to rise tomorrow and keep ascending into the weekend.

Winds Base: 5-10 E Ridge Top: 5-15 E Trend and Timing: Easterly winds will be gusty and persistent.