On the radar this afternoon you can see there are 2 distinct rounds of precipitation.
The one that is moving through now is overrunning, which is warm air moving over colder air and producing moderate to heavy precipitation, rain for most of the forecast area, although it started as a mix Middlesex county North very briefly, NW NJ like Sussex County to Passaic county started as heavy snow and accumulated 1-2 inches now the transition to sleet and eventually rain is happening rather quickly
I expect all of NJ to be plain rain very soon, and after round 1 ends warm air aloft will come in and make sure of that, for the areas that have rain, .25-.50 has fallen with a few more hours to go in round 1 where we could see another .10-.25 with round 1
Round 2 is to our SW as a line of heavy rains and thunderstorms. This will move N & E tonight and affect East PA , NJ , NYC with heavy rain and maybe an isolated thunderstorm but the air is much more cold and stable here so I expect that heavy rain is the main concern, also a secondary low will develop off the NJ coast and enhance rain/ precip so we still have a long ways to go, we should at least double what we have now, and showers are expected to last till early to mid morning tomorrow.
As the coastal develops , cold air will try to come back in so NW NJ and NE PA could get more sleet and snow, at least a little bit anyway and CT also, all have had minor accumulations and may get some more tonight, but most of the forecast area is rain and minor flooding is possible as a grand total of 1-1.50 inches is expected from NYC to Cape May, 1.50 more likely in south NJ