MOUNTAIN WEATHER FORECAST

Stevens Pass Mountain Weather Forecast

Day and Time: Thursday 0900

The Snapshot:  Giving thanks for snow.   Snow tonight and tomorrow.   

Snow total values by 4am Saturday will be 8-10” in the base area with 10-15” on the upper mountain.

Current Observations:

Precipitation: It is lightly snowing with 3” of new snow in the base area and 7-10” on the upper mountain.  

Pass temperature: 29base/31ridge

Pass level Winds: 5-10 E

Barometer:  1004 mb’s and falling

Sky: Overcast

Radar: Light scattered snow showers in the Snoqualmie Pass convergence zone with the next big system just making landfall.

The Forecast: Intermittent snow showers will persist today with snow increasing after sundown tonight. Snow continues through early Saturday morning.

Long Range: There will be a break in the moisture on Saturday with partial clearing possible.  The next storm enters the mountains late Saturday night/early Sunday morning. This is a warm front with freezing levels potentially rising above 5000’ with moderate rain.    

  

The Science: Current infrared satellite imagery has and occluded/cold front  pushing the next round of moderate to heavy precipitation into Olympic mountains.   The front is timing out to pass over Stevens Pass after sunset tonight. (+-7pm or later).  Once the front passes, the cool easterly flow will be over taken by westerly winds with good orographics filling in.  The Puget Sound Convergence zone(s) will become active during the next 24-36hrs.  Freezing levels are expected to remain steady around 4000’.

A high pressure ridge between storms moves through on Saturday with a SW flow warm front event arriving on Sunday/Monday.     

Values from 4am today through

 4am tomorrow.

Precipitation: Today 24hr water: .5-.75  snow: 3-5 Tomorrow’s 24hr water: .75-1  snow: 7-10 Trend and Timing: Snow will increase tonight and fall through early Saturday morning.

Temperature: Low: 28    High: 34 Freezing level: 4000’-4500’   Trend and Timing:    Freezing levels will hold around 4000’ today and rise slightly to 4500’ overnight.

Winds Base: 5-10 E shifting W Ridge Top: 5-10 SSW shifting W Trend and Timing: East flow at the surface with SW flow above 5000’ will be the wind pattern today.  Winds shift westerly around midnight tonight.