The National Weather Service has issued severe thunderstorm warnings in several New Jersey counties Friday afternoon as strong storms with gusty winds, hail and the potential for a tornado sweep across the state. One thunderstorm warning was issued at 3 p.m. and covers parts of Burlington, Camden and Gloucester counties. It is effective until 3:45 p.m. Friday, and the weather service said this storm cell could produce 60 mph wind gusts and hail as large as ping pong balls. Another thunderstorm warning was issued just minutes after the first one and covers parts of Hunterdon, Mercer and Somerse…