Some wet snowflakes have been spotted in the region, but temperatures remained well above freezing with clouds parting for the setting sun.
However the National Weather Service is saying that a strong cold front could set off snow squalls sometime after 7 p.m. that could slicken the roads as temperatures fall.
It also has issued a high-wind advisory, with gusts up to 50 m.p.h., and warns that they might cause scattered power outages and lower visibility if those squalls do happen.
As for the snow, if a tenth of an inch or more is recorded officially at Philadelphia International Airport/National Park, it would be the first measureable snow of the season.
That would be the 10th-longest wait in the period of record, dating to 1884, for that first snow.
Philadelphia already has set a record for the longest wait for even a "trace" of snow.