MOUNTAIN WEATHER FORECAST

Stevens Pass Mountain Weather Forecast

Friday, December 06, 2019, 0830a  

Current Observations:

24hr Precipitation:            0 swe

Temperature profile:        31 base,  30 base

Pass level winds:                light easterly

Barometer:                       1014mb and rising

Sky:                                morning fog and patchy upper level clouds

Radar:                        rain showers developing along the coast and tracking north

The Forecast:  Increasing clouds today with mixed rain and snow developing tonight.  Mostly rain showers tomorrow with a few inches of snow accumulation possible on the upper mountain.

Long Range:  Sunday through Wednesday will be mostly dry and warm with clear periods.  The next chance of snow will be Thursday through Sunday. 

  

The Science:  There is a stationary front draped along the US/Canadian border with a cold front tracking in from the SW.  This complex system will bring a mixed bag of moisture to Stevens Pass over the next 24hrs.  East flow is moving through the Pass this morning and is expected to continue through the night.  There isn’t a ton of cold air to the east but hopefully this will aid in lowering snow levels to or just below 4000’.

The cold front is timing out to pass east of the crest early tomorrow morning. Once this occurs, the moisture will begin to diminish.   A high pressure ridge developing behind this system will drift east over the region on Sunday.  Thus, expect a dry end to the weekend with cool, dry and clear weather for the start of the week.

Long range models are in disagreement for what is to come on Thursday. The ECMMF (European model) has a progressing front with snow and the GFS (USA/NW) model has the moisture staying to the west with higher pressures developing over the inland NW.  In short, confidence is pretty low for the long range outlook.  So, as usual, stay tuned. 

Forecast confidence: Fair to poor.

Values from 4am today through 4am tomorrow.

Precipitation: Today 24hr water: .25  snow: 1-3 Tomorrow’s 24hr water: .25  snow: 0-2 Trend and Timing: The moisture will arrive after 4pm today with light mixed forms of precipitation falling through tomorrow afternoon.

Temperature: Low: 30  High: 36 Freezing level: 3500-4500’ Trend and Timing:    Freezing levels will hover around 4000’ today and then begin to rise tomorrow.

Winds Base: 0-5 E Ridge Top: 0-10 ESE Trend and Timing: Pass level east flow with SE flow aloft will be the wind pattern through the night with winds shifting SW tomorrow.