MOUNTAIN WEATHER FORECAST

Time and Day: 0630 Tuesday

The Snapshot: There is a winter storm warning for the mountains today.  1-2 feet of snow will be possible.  Sporty!  

The Science

Current Observations:  5” of snow fell yesterday with no new snow overnight.  High clouds are beginning to moving in with temperatures in the mid 20’s.  The winds have shifted easterly and the barometer is at 1017mb’s and falling.   Satellite imagery has the leading edge of the approaching storm just hitting Seattle.   

The Forecast:  The storm is expected to enter the mountains this morning with heavy snow and rising temperatures expected through the day.  The storm is moving slowly and may stall prior to hitting the western slopes – so the timing of all this is suspect.

East flow and cooler air aloft will do it best to shelter Stevens Pass from the warm air advection.  If this holds true, we shouldn’t see much in the way of rain.  The freezing levels are expected to peak to 4-4500’ late tonight and then begin to fall through the day tomorrow.

 The following cold front will swing in sometime tomorrow morning which will shift the precipitation to showers and begin to drop the temperatures.       

The Long Range:  The large low-pressure system churning in the Gulf of Alaska will continue to drive storms into the PNW through the weekend.    

24hr values daily 4am to 4am.

Precipitation: Today 24hr water: 1-1.5  snow: 10-15 Tomorrow’s 24hr water: .5-.75  snow: 4-6 Trend and Timing: Heavy snow arrives this morning and will shift to showers early tomorrow morning.

Temperature: Low:  24   High: 32 Freezing level: 3000’ 4500’ Trend and Timing:    Freezing levels will slowly rise over the next 12-24hrs peaking near 4500’ late tonight.  Temperatures then fall in the wake of the cold front tomorrow.

Winds Base: 0-5 E Ridge Top: 5-10 E shifting WSW Trend and Timing: East flow should hold through the night with winds shifting WSW in the wake of the passing cold front tomorrow.