In the last 18 hours, the National Weather Service snow maps have undergone changes, with winter-storm watches now posted for Chester and Delaware Counties.
The map shows up to 6 inches in far southwestern Chester County, and 2 to 4 in and around Philly.
Should that hold, this would become the heftiest official snow of the season in Philadelphia, where the biggest total of the season has been a paltry 1.5 inches.
That's by no means a lock, however, and accumulating snow confronts a mighty obstacle in the calendar.
With the increasing power of the sun, paved surfaces all over the region are becoming poor man's hot plates.
The precipitation is forecast to arrive before daybreak and then continue throughout the day. Even if it is all or mostly snow, it would have to come down with a vengeance to stick any place other than car roofs, mailboxes, and tree branches.
Even behind the clouds, the March sun can exert a powerful force against accumulating snow, so to get significant accumulations, the snow almost certainly would have to keep falling well into tomorrow night.
Right now, that is no sure thing.
As Walter Drag at the weather service has suggested, this could well become another case in which elevated areas wind up with several inches and postcard snow cover, with white rain for anyone near sea level.
We would point out that Philadelphia snowfall is measured officially in National Park, Gloucester County, directly across from the airport, and getting to 2 inches might be a challenge.
In any event, road conditions on the major highways are unlikely to be a problem until after dark.
Final snow totals are going to depend greatly on how quickly the coastal storm pulls out to sea.
This has been the season of what Drag's boss, Gary Szatkowski, calls the "penny" snow, with snowfalls too anemic to rise to the level of "nickel and dime."
Snow has been detected officially on 29 different days this season, yet the seasonal total stands at a mere 7 inches.
It's entirely possible that at least officially in Philadelphia, this will end up being another penny special.