December 4, 2003
By now you may have guessed (or heard) that our first accumulating snowfall of the season for the Delaware Valley is less than 12 hours from onset. However, there will actually be 2 different storm systems causing inclement weather in our area over the next couple of days.
An very potent upper level storm center will/is diving Southeastward out of Canada through the Dakotas, and on into the Tennessee Valley. This is system #1 in which precipitation has already overspread parts of Maryland and into DC at the time of this update. The surface low associated with this disturbance will follow a Miller C type scenario (across the Tennessee Valley) and will develop a secondary area of low pressure off the Carolina coastline by Friday morning. Snow and sleet will overspread our area by daybreak and may accumulate lightly before mixing with and/or turning to plain rain showers during mid-morning in parts of the area. North and West of the city could see a prolonged snow event with accumulations of perhaps 3" in parts by Friday evening.
As the day goes on Friday, the upper level disturbance will begin to interact with the secondary surface low East of Virginia and will try to "capture" it, or slow down it's Northeastward progress. Yes, this means the storm system slows down, strengthens, and since it is well East and South of the area, it will draw in colder air from the North, and more moisture from the Atlantic allowing for any rain showers to turn to a steady snow Friday night. Snow will be moderate to heavy at times and should taper to flurries later in the day on Saturday.
Total snowfall accumulations will be anywhere from 6-12" for our immediate area with potentially higher totals just to our North and West. As guidance continues to pump information out, I will draw conclusions and continue to update, time permitting. Don't be surprised if this storm becomes the heaviest early December snowfall since 1960 for parts of the Middle Atlantic and Northeast. Parts of those areas stand to get clobbered pretty good from this one with some guidance dropping in excess of 20" for some. More later!
S.B.
