I just saw the same thing at 7:20 PM we had a storm move in which produced very small hail. I noticed a very noticeable lowering towards the west around the newark bay.
Thats when i got a better view and saw a cone shaped cloud. I took a photo but is really low quality so my apologies in advance.
Couldn't tell if it was rotating as Im blind as a bat. It's probably nothing but then again, it really did have that look...Don't think we'll ever know