MOUNTAIN WEATHER FORECAST

Stevens Pass Mountain Weather Forecast

Saturday, November 23, 2019, 0830

Current Observations:

24hr Precipitation:          0

Temperature profile:       32 base, 33 ridge

Pass level winds:               light westerlies

Barometer:                        1022mb’s holding

Sky:                                  Overcast

Radar:      Heavy rain falling in the NW corner of the State with the leading cloud deck moving SE into Washington.

The Forecast:  Windy and wet tonight with rain changing over to snow showers tomorrow.   

Long Range:  Snow showers with falling temperatures will be the weather pattern through the middle of next week.  Thanksgiving day will be mostly dry with light passing snow showers possible through the holiday weekend.

Snow totals from Sunday 4am through Wednesday 4am ranges between 6 and 12” of snow.   

  

The Science:  The high pressure that has been parked over the PNW will flatten today and drift south.  This will open the door for a significant pattern change.  NW zonal flow with imbedded cold fronts will drive SE along the NW coastal waters over the next 24hrs.  The warm air aloft will take some time to erode with freezing levels hanging around 5000’ through early tomorrow. 

An atmospheric wave associated with the low pressure trough will bring heavy precipitation and high winds to Stevens Pass tonight.  The trailing cold front will then swing in with lowering freezing levels and diminishing precipitation.

The long range pattern will settle into a cool unstable NNW flow with snow showers and low temperatures expected throughout the Holiday week.       

Forecast confidence: Fair

Values from 4am today through 4am tomorrow.

Precipitation: Today 24hr water: .75 snow: 1-3 upper mountain, trace in base area. Tomorrow’s 24hr water:  .25+  snow: 2-4 Trend and Timing: Rain arrives around sunset tonight with heaviest period between midnight and 7am.  Intermittent snow showers expected through the day tomorrow.

Temperature: Low: 30  High: 36 Freezing level: 5000’- 4000’ Trend and Timing:    Freezing levels will slowly begin to fall tonight dropping below 4000’ early tomorrow morning.

Winds Base: 5-15 W Ridge Top: 10-20 W gusty Trend and Timing: Winds will increase tonight with 40+ ridge top gusts likely. Winds diminish and shift NNW tomorrow.

jM