MOUNTAIN WEATHER FORECAST

Stevens Pass Mountain Weather Forecast

Day and Time: Tuesday 0700

Current Observations:

24hr Precipitation:  0

Temperature profile: 15 base, 19 ridge

Pass level winds:  Gusty but light, out of the east

Barometer: 1013mb” and falling

Sky: Partly cloudy

Radar:  The state is mostly dry with increasing clouds to the west.   

The Forecast:  Two more days of dry, cool weather is expected.

Long Range: Snow begins early Thursday morning with another weak wave of moisture passing through on Friday.   Warmer with mixed precipitation is taking shape for the weekend.  

  

The Science: Cooler temperatures are moving up the eastern slopes due to increasing pressure gradients. That, and the dropping barometric pressure are indications of the weakening high pressure.  However, the high pressure ridge will be slow to give up the fight keeping the Cascade Mountains mostly dry through early Thursday morning.

 A well-organized low pressure system will spin bands of moisture up from the SW on Thursday.  Freezing levels will be on the rise, but east flow doing its thing for the first few waves of moisture.  There isn’t a ton of moisture associated with these bands but we should get a few inches of snow on the ground by Friday.

Confidence is good through Friday.

Values from 4am today through

 4am tomorrow.

Precipitation: Today 24hr water: 0  snow: 0 Tomorrow’s 24hr water: < .25 snow: 1-3 Trend and Timing: Dry today with light snow beginning early Thursday morning.

Temperature: Low: 20    High: 30 Freezing level: +-2500’ Trend and Timing:    < 2000’ FL’s to the east with 5000’ FL’s to the west.  East flow will keep temperatures below freezing at Stevens Pass today.

Winds Base: 5-15 E Ridge Top: 5-10 E Trend and Timing: Easterly winds will continue to be gusty.

Glossary of PNW Weather Terms: 

Storm Water Equivalent (SWE)…. how much water is in the snow or rain

Orographic lift…. an airmass that is lifted as it moves up and over higher terrain. This promotes cloud development, and enhances precipitation.

Dirty Ridge…. a weak, unorganized high pressure ridge.

Advection…. the transfer of heat by the flow of fluid.  For the PNW, this is usually from warm moist air entering the region from the south.

Flow…. wind direction.  In meteorology, the wind direction is always noted where the wind is coming from.   East flow is wind coming from the east; SW is from the south west…

Intermountain West…. the mountain ranges between the Rockies and the Cascades.  Mainly Idaho and Western Montana.