MOUNTAIN WEATHER FORECAST

Stevens Pass Mountain Weather Forecast

Day and Time:

The Snapshot:  Enjoy today because there a storm-a-brewing. Snow changing to heavy rain tonight, rain and wind tomorrow.    

Current Observations:

Precipitation:  Dry   

Pass temperature: 33

Winds: 5-10 W

Barometer: 1022mb’s holding

Sky: high clouds

Radar: There are few spotty showers of mixed rain and snow showing along the spine of south central Cascades.  

The Forecast:  Today will be mostly dry with the main moisture event arriving after 7pm tonight.  Mixed rain and snow below 4500’ with snow on the upper ridges are expected tonight.  Warmer temperature with heavy rain and wind can be expected tomorrow. 

Long Range: Several pulses of moderate to heavy precipitation will move through the region over the next 5 days.

  

The Science:  An impressive storm with strong pressure gradients and a SW fetch of moisture is tracking toward the PNW.   Freezing levels will hold around 4000’ as this warm front approaches.  Once the front passes east of the crest (+-midnight) temperatures will rise and the heavy rain will kick in. 

Wind.  Pressure gradients will tighten in the wake of the front and produce some consistently high westerly winds.  SW flow will keep the high winds at bay until it shifts more westerly tomorrow.  Models have 5000’ winds blowing 20-40mph starting after 7am tomorrow.  Winds could persist into Thursday as well.   

The general flow aloft will be WSW through early Friday. A shift in the jet stream develops over weekend.  This may allow some cooler NW flow to develop early next week.   

Values from 4am today through

 4am tomorrow.

Precipitation: Today 24hr water:.5+   snow: 1-3 Tomorrow’s 24hr water: 1-2  snow: 0 Trend and Timing: Mixed rain and snow starts after sunset with heavy rain expected overnight and tomorrow.

Temperature: Low:30     High: 38 Freezing level: 4000’-6000’ Trend and Timing:    Freezing level bottom out near 4000’ tonight and then sharply rise after midnight.

Winds Base: 0-5 W Ridge Top: 5-10 SSW.    Trend and Timing: Winds will be light today and increase after 4am tomorrow morning.   5000’ ridge top winds will be +-20mph once the flow shifts from SW to W tomorrow.