Mountain Weather Forecast

Stevens Pass Mountain Weather Forecast

Day and Time: Saturday 0630

Welcome to June-uary

Current Observations:

24hr Precipitation: 0” 

Pass temperature:  32 base/28 mid-mountain

Pass level winds: Light, easterly

Barometer:  Steady around 1016

Sky: Clear with mid-mountain fog inversion

Radar: Light fog in Puget Sound

The Forecast: Pass level inversion conditions, bringing the normal package of east flow, intermittent fog, and base area temperatures near freezing with warmer upper air temperatures. No precipitation expected for the next 72 hours.

Long Range:  Dry with offshore flow and inversion conditions thru Tuesday. The upper level large scale features begin to break down mid-week, allowing a return to active weather by the end of the week. Keep the faith.

  

The Science: High pressure over the PNW is anchored between two stationary lows this morning. These conditions support offshore (easterly) low level air flow thru the Cascade passes. Cold air sinks to the valleys east of the crest, condenses into fog and clouds, and is then pushed thru the passes by the pressure gradient. Thus we end up with cooler local temperatures and intermittent fog layers, with warmer air aloft. The upper level air mass is stable and dry, so high freezing levels and no precipitation are expected until something changes. Remember when we got snow last week while it was raining elsewhere? This is the flip side of that coin.

Values from 4am today through

 4am tomorrow.

Precipitation: Today 24hr water: 0  snow: 0 Tomorrow’s 24hr water:  0 snow: 0 Trend and Timing: No precipitation expected for the next few days.

Temperature: Low: 29    High: 33 Free Air Freezing level: 8,000’, local freezing level ~4,500’ Trend and Timing:    Inversion conditions will persist thru the weekend.

Winds Base: E 5-10 Ridge Top: Variable, mostly ESE 5-10 Trend and Timing: Offshore flow thru the passes will continue for the next few days.