MOUNTAIN WEATHER FORECAST

Stevens Pass Mountain Weather Forecast

Day and Time:  Monday 0630

The Snapshot:  Mixed snow and rain this morning will turn to all rain this afternoon. Diminishing rain showers tomorrow with cooler temperatures and snow at times for the remainder of the week.

Current Observations:

Precipitation: Light rain in the base area with mixed snow and rain on the upper mountain

Pass temperature: 30

Pass level winds: 0-5 E

Barometer: 1017mbs and falling 

Sky: Overcast

Radar:  The radar is lit up this morning with heavy rain and high winds throughout western Washington. Mixed snow and rain below 4500’ with snow in North Cascades

The Forecast:  The snow will switch to all rain today as the freezing level rises above 5000’.   The heaviest period of rain is expected tonight.  The rain tapers off tomorrow with snow showers expected on Wednesday.

Long Range: There is quite a bit of discrepancy in the models from Thursday – Sunday.  So as of now, there is a chance of a few inches of snow late Wednesday night/Thursday morning and then again on Friday.  The weekend appears to be dry and cold.  

The Science:  The leading warm front of the approaching triple point storm is just about to make land fall.  This storm has a large moisture stream stretching out to the SW.   Strong warm SW flow will overtake the weaker cold east flow over the next 12-24hrs.  The associated cold front is timing out to move through tomorrow morning.  Once the cold front passes east of the crest, the moisture stream will be cut off and the flow will shift westerly. Pressure gradients will also loosen tomorrow afternoon helping to break up the precipitation.  

A weak cut off low will swing through late Wednesday night producing a short period of moisture – possibly snow.  Another similar event will occur on Friday.

Values from 4am today through

 4am tomorrow.

Precipitation: Today 24hr water: .75-1  snow: 0-2 base, 2-4 upper mountain Tomorrow’s 24hr water: .5   snow: 0 Trend and Timing: Light to moderate snow/rain today turns moderate to heavy rain tonight. Rain tapers off after 7am tomorrow.

Temperature: Low: 32    High: 36 Freezing level: 4000’- 6000’ Trend and Timing:    Freezing levels will rise above 5000’ today. East flow at the surface will keep temperatures just above freezing through noon or so today.

Winds Base: 0-5 E Ridge Top: 5-10 SSE Trend and Timing: Pass level easterly winds weaken today and shift SW tomorrow.  Upper level winds will be generally southerly.