Friday, December 23, 2011

Dry Through Christmas, Rainy Next Tuesday

A couple of emails today addressed the fizzled Christmas storm and what caused the "fizzling" in the storm.  It's not so much a fizzling but a delay.   I've posted a map of the mid levels on the GFS model for Sunday.  The orange "donut" over Texas and Oklahoma is the wave of energy that was supposed to push out and set up that Christmas system.  However, compared to earlier projections in computer modeling, that wave has moved much more slowly and has held back across the South due to the northern branch of the jet not dipping down as sharply in the Midwest to help "kick" the storm along.  The flatter jet across the northern parts of the country will result in this southern system taking its sweet time to move across the South and then to the East Coast.

The timing on this system suggests a Tuesday arrival of rains into the Mid Atlantic -- generally into the afternoon and evening but arriving into Delaware and Maryland early in the morning on the 27th.  This should be rain for most...could start as snow or sleet north of I-78 before temperatures aloft moderate above freezing.   The snow/sleet start in the Poconos and upper Lehigh Valley would seem plausible if the system arrives early enough in the day...but odds favor the brunt of rain falling in the afternoon and evening hours.   Like last night's system, this could bring another inch of rain to some of us in the region but there's still a good deal of fine-tuning to be had with this system before it hits.

Snows will generally fall across the Twin Tiers of New York and Pennsylvania...just not around here unless this storm tracks farther east, stronger, and colder over the next three days.  Right now, that is rather unlikely.