MOUNTAIN WEATHER FORECAST

Stevens Pass Mountain Weather Forecast

Date: Saturday, December 28, 2019

Current Observations:

24hr Precipitation: .15” SWE / 2” snow

Temperature profile: 27 base / 26 mid mtn

Pass level winds: Light westerly

Barometer: 1018 steady

Sky: Overcast

Radar: Light, spotty showers near the crest

The Forecast: Partly cloudy with a snowflake or two possible today. Warmer temps and partly cloudy Sunday.

Long Range:  The weak ridge remains in place Sunday and Monday, allowing for mild days with a few sun breaks. The next chance for snow arrives Tuesday/Wednesday, with a pattern shift looking possible for the end of the week. Stay tuned.

  

The Science: A weak low pressure center will flop onshore today, becoming cutoff from the main upper level flow and basically shearing apart. It will mostly have the effect of bringing a warmer airmass into our area, rising freezing levels and surface temperatures. East flow should develop this afternoon, bringing potential inversion conditions to the mountain passes.

A very positively tilted (ridge axis oriented more west-east) upper level high will move in on Sunday. This configuration of ridge will often allow clouds and light moisture to stream over the top of it and is referred to as a “dirty” ridge. Thus, not expecting full sunshine on Sunday.

Confidence: Good

Values from 4am today through 4am tomorrow.

Precipitation: Today 24hr water: .10  snow: Trace Tomorrow’s 24hr water: 0  snow: 0 Trend and Timing: Light snow flurries possible Saturday, no precipitation expected Sunday.

Temperature: Low: 26   High: 32 Freezing level: 3500-4000 Trend and Timing:    Warming aloft thru Sunday, surface temperatures may stay lower due to east flow influence thru the pass.

Winds Base: Light and variable Ridge Top: W 10-15, then ENE 5-10 Trend and Timing: Winds shifting easterly Saturday afternoon and overnight.