When I had painted turtles, I kept them outside for the summer in a 500+ gallon pond. In the winter I always brought them inside. Sure, they are native where I lived, but i didn't want to take any chances. Plus my pond wasn't that deep (2 feet).
This lady at my work wants to try to leave her 3 baby painted turtles outside this winter in her pond. I told her that she should probably bring them inside for the winter but they could over winter there. I told her she needs to have alteast a foot of mud for them to bury into. A stock tank heater on your pond is a good idea as well so you don't have to worry about Carbondioxide building up as well as thick ice accumulating.
Your turtles are RES, there native range is the Mississippi valley, but they do live in introduced locations all over the world that have worse winters then NJ. So I would think your turtle could survive outside but I don't recommend it.