January 15, 2003
The threat for snow on Friday is becoming more of a liklihood as time goes by. The question still stands, just how much of the white stuff do we receive? In short, the potential is there to receive anywhere from a few flurries and/or snow showers up to a significant accumulation (greater than 4").
Now the details. Two areas of upper level disturbances will be combining (phasing) to creat a decent snowstorm for some of the big cities in the East of Friday. Among those in the "line of fire" at the moment are Washington, DC (best chance), Philadelphia (odds increasing tremendously), New York City (Northern edge), and Boston (Northwestern edge).
The two vortmaxes will pahse, at least partially, over the Tennessee Valley late Thursday. At the surface, an area of lower pressure will be pushing out of the four corners region late on Wednesday or very early Thursday and will continue to head NNE in response to the upper low closing off, again, in the Tennessee Valley later on Thursday.
The trend for the past 36 hours on most guidance is to track the system slightly farther North and West each run (actually in response to the Northernmost vortmax hanging back farther West over Iowa instead of Northern Indiana). In all actuality, the track of the surface low is only about 50 miles farther North and West at this time. The big deal is that RH and QPF is increasing in the Northern and Northwest Quadrant with each successive run.
Again, feeling is that guidance is not completely through with the Northern shift. Should see yet another shift or two at 0Z and 6Z (12Z?) until the heaviest bacn is right on DCA and perhaps into Central and Southern Delaware, and Southern New Jersey. Still a few details to hammer out in regards to timing of upper level systems, but confidence is near average regarding the Friday system.
Temperatures will remain quite cold with highs struggling to get above freezing for at least the next 5 days. Conditions for the EAGLES game on Sunday is for variably cloudy skies, brisk and cold with wind chills in the single digits. Temperatures will be in the 20s for the first half, and may dip into the teens later in the game with the chance for some light snow.
Again, our chances are steadily increasing for a significant snowstorm in the PHL region on Friday. Right now, the heaviest snows look to set up near DCA, but any shift farther North could spell much more snow for Philly. Will go with a period of snow likely on Friday for PHL. Some accumulation expected at this time. Highs in the upper 20s. Take care!
S.B.
