The computer models still have details to resolve, but right now it appears that the only question is whether this will be a significant or a very significant snowfall.
The latest run of the U.S. model would suggest about 10 inches for Philadelphia, says Henry Margusity, a meteorologist with Accu-Weather Inc.
That's assuming the precipitation would be all snow, which is not yet a certainty. Temperatures are going to be borderline, probably quite close to freezing. In its morning discussion, the National Weather Service expressed low confidence in its snow forecast. It has not yet upgraded its winter storm "watch" to a "warning."
Regardless, Margusity believes this one will be remembered more for wind than snow amounts, in a region jaded by this season's mega-totals. The wind will the real deal, he says, with gusts up to 60 m.p.h.
"This is a more serious storm," he said. "It's going to look impressive out there tomorrow evening. People are going to be saying, 'Wow, it's really windy.'"
He went so far as to say that people who live north and west of the city should think twice about going out tomorrow evening because conditions are going to be nasty, and power lines could be falling.
It is not out of the question that this will match the most-recent winter storm for power outages. In all, PECO reported 225,000 outages in that one, making only the second snowstorm to make the top 10 list for power-loss events.
The only other snowstorm was the potent "Equinox Storm" of March 19-21, 1958, which left about a foot of heavy-wet snow in Philadelphia and up to 3 feet in Chester County.