MOUNTAIN WEATHER FORECAST

Stevens Pass Mountain Weather Forecast

Wednesday, January 29, 2020, 0800

Current Observations:

24hr Precipitation:        .02swe, 0’ of snow thus far

Temperature profile:      32 base, 30 ridge

Pass level winds:              light, easterly

Barometer:                    1017mb’s and falling

Sky:                                OC and lightly snowing

Radar:          heavy moisture heading into the moisture with an embedded warm front attached.

The Forecast:  Heavy snow today with some mixed rain possible below 4500’.  The moisture tapers off tonight with tomorrow being mostly dry.  Rain arrives tomorrow night.   

The Science:   An approaching triple point frontal system, holding a good batch of moisture, will bring heavy snow to the mountains today.  The leading warm front will spike freezing levels to +-4500’ this afternoon.  The trailing cold front will swing through tonight, cutting off the moisture, thus this snow event will be relatively short lived.  

A weak high pressure ridge between storms will bring dry weather with some partial clearing tonight and tomorrow.

The incoming rain event:    Models are starting to align with the incoming rain event starting tomorrow night.  Strong SW flow with warm air convection will push freezing levels to +7000’ by Friday morning.  There may some snow on the front end and tail end of this storm but, for the most part, it will be full on rain.

Early Storm Water Equivalent (SWE) calculation are 2.5”- 4” between 10pm Thursday and 4am Saturday.  

Long Range.   The rain is expected to stop sometime early Saturday morning with cold air arriving over the weekend.  With some luck, we could see a little snow accumulation Saturday morning as this storm exist the region.   

Confidence:   Good.

Values from 4am today through 4am tomorrow.

Precipitation: Today 24hr water: .75 snow: 6-8    Tomorrow’s 24hr water: .75-1   snow: trace Trend and Timing: The snow will be the most intense this afternoon with drying beginning after 7pm tonight.  Little snow is expected overnight.

Temperature: Low: 28   High: 34 Freezing level: 4500’ Trend and Timing:    Freezing levels will spike up to 4500’ today and then fall back to 4000’ tomorrow.

Winds Base: 0-5 E Ridge Top:  5-15 SWS gusty Trend and Timing: Light east flow at the surface will switch SW overnight.  Gusty ridge top winds will kick-in this afternoon as the front passes, but they should be fairly short lived.