MOUNTAIN WEATHER FORECAST

Time and Day: 0700 Tuesday

The Snapshot:  Clear this morning with an amazing sunrise.  High clouds, warm air, and precipitation will move in later today.  Snow arrives this evening with a possible powder day shaping up for tomorrow.  Thursday will be mostly dry with more snow on Friday and then again on Saturday.

Note: Depending on the timing of this storm, a short period of freezing rain may be possible this evening on the east slope roads. 

The Science

Current Observations: The temperature profile is inverted with the base area temperature at 22f and the Tye Mill telemetry site reading 29f.  The barometer is 1022mb and holding steady at the moment.  The 5000’ winds shifted SW yesterday evening and have eroded the east flow at the surface.   Satellite images show the leading edge of the approaching frontal system just off the BC coast and tracking SW.

The Forecast:  The warm air aloft is in response to the approaching storm tracking in from the NW.  This is a triple front storm which, as we have experienced in the past, will bring a warm front with rising freezing levels following cold front and dropping temperatures.  This storm is also entraining a long fetch of moisture strung out to the SW.  The Puget Sound Convergence Zone will also play a role with gusty westerly winds through the night.

The day will likely play out like this:  Freezing levels rising to 5000’ by noon or so and then fall below 4000’ early this evening. (+- 7pm).  Models currently have the moisture arriving after the cooldown so good news there.  The main bulk of moisture (snow) begins after 4pm with moderate snow falling through noon or so tomorrow.  With some luck, we could have a foot of snow on the ground by days end tomorrow.  

  

The Long Range:  Another system arrives early Friday morning with snow likely through the weekend.      

24hr values daily 4am to 4am.

Precipitation: Today 24hr water: .5  snow: 4-6 Tomorrow’s 24hr water: .5  snow: 4-6 Trend and Timing: The precipitation starts after 4pm today and diminishes to showers tomorrow afternoon.  Convergence conditions will play a factor in snow totals.

Temperature: Low:24     High: 36 Freezing level: 3000’-5000’-3000’. Trend and Timing:    Windy conditions can be expected.

Winds Base: 5-10 W Ridge Top: 10-20 W Trend and Timing: Westerly flow will dominate the wind pattern through tomorrow.