MOUNTAIN WEATHER FORECAST

Time and Day: 0700 Thursday

The Snapshot:  A good powder day is shaping up for tomorrow.  Moderate to heavy snow today with snow tapering off tomorrow.  The sun, with a taste of spring, arrives for the weekend.

The Science

Current Observations:  It is beginning to snow this morning with 1” showing up on the telemetry.  The temperature profile is 27 base /  23 ridge. The barometer has dropped to 1008mb’s.  The winds are easterly 5-10mph.   The radar has the leading edge of the approaching moisture entering the Puget Sound area and tracking east.

The Forecast:   The approaching frontal system elongated and occluded last night which means that the warm air and cold air have mixed. Good news for us because it will allow a less dramatic temperature spike this afternoon. Freezing levels are expected to reach 4000’ today and nudge up to 4500’ this evening.  East flow will help keep Stevens Pass in snow through the day with a short possibility of some mixed rain below 4500’ this afternoon.

A cold front will swing in tonight.  Once the cold front passes east of the crest, the winds will shift westerly and increase,  the Puget Sound Convergence Zone kicks in and the freezing level will drop.  The snow tapers off by noon or so tomorrow with another high pressure ridge moving into place.   

The Long Range:  A blocking ridge of high pressure under warm southerly flow will bring our first taste of spring this weekend.  Sunshine with daytime temperature reaching into the 40’s can be anticipated.

24hr values daily 4am to 4am.

Precipitation: Today 24hr water:  1 snow: 10-12 Tomorrow’s 24hr water: .25 snow: 2-5 Trend and Timing: The main snow event starts this morning and increases in intensity this afternoon/evening.  Snow ends mid-day tomorrow.

Temperature: Low: 24    High: 34 Freezing level: 4500’ – 3000’ Trend and Timing:    Freezing levels will peak near 4500’ this afternoon and drop to 3000’ after midnight.

Winds Base: 0-5 E shifting W Ridge Top: 5-15 ESE shifting W Trend and Timing: East flow will hold today with increasing westerly winds kicking in late this afternoon.  Winds will be consistent through the night.