The latest NAM data is becoming available. Precipitation, very light, expected to begin about 7 am Wednesday. As I’ve been saying since last night, temperatures in the upper atmosphere will be too warm to support snow in Philadelphia and the immediate adjacent PA counties and south Jersey.
In the lower levels of the atmosphere and at the surface, temperatures remain below freezing until 9-10am in and around PHL, so precipitation will fall as a brief period of light sleet and then light freezing rain, changing to all rain by late morning.
The issue for tomorrow morning will be icy conditions on untreated surfaces, not accumulations. Even a thin coating can be slippery.
One more thing…QPF values are very low in the morning, less than 0.09 inches water. The heavy rain will be during the afternoon.