MOUNTAIN WEATHER FORECAST

Stevens Pass Mountain Weather Forecast

Day and Time: Monday 10:00

The Snapshot:  Warming with increasing clouds today.  Rain arrives late tomorrow night and continues through the week. 

Current Observations:

Precipitation: 0 

Pass temperature: 28

Winds: 0-5 NNE

Barometer:  1029mb’s falling

Sky:  Mid to high level cirrus clouds

Radar:  Dry throughout the state.  

The Forecast:  Freezing levels will begin to rise today with rain moving in tomorrow night.  Intermittent rain showers with clear periods will persist for the remainder of the week.  Freezing levels will be above 5000’ for the remainder of the week as well.

 Long Range: The weekend will be dry and clear as another high pressure system builds over the PNW.    

  

The Science:  The high pressure responsible for this past stretch of clear weather is drifting east into the intermountain west.  This will open the door for warm air advection to drive in from the SW and erode the east flow/temperature inversion.  A band of moisture will slide in from the NW late tomorrow night.  The atmosphere will remain unstable under moderate westerly flow Wednesday – Friday.    

Note: the GFS, NAM and ECMWF models have slight disagreements on the timing of these events but the general gist the same. 

Values from 4am today through

 4am tomorrow.

Precipitation: Today 24hr water: 0  snow:0 Tomorrow’s 24hr water:.25-.5   snow: 0 Trend and Timing: Dry through 4pm tomorrow afternoon.

Temperature: Low: 24    High: 40 Freezing level: 4500’ – 6500’ Trend and Timing:    Freezing levels will slowly rise today peaking near 7k tomorrow.

Winds Base: 0-5 E Ridge Top: 5-10 ESE Trend and Timing: East flow will continue with gusty down slopes possible. The flow will slowly shift SW then westerly starting tomorrow.