The National Weather Service extended its excessive heat warning and heat advisory through 8 p.m. Sunday for most of New Jersey, plus elevated the risk of severe weather Sunday afternoon for much of the state. An increasing chance for showers and thunderstorms, along with damaging winds, was elevated to a level 2 out of 5 for parts of New Jersey Sunday afternoon and evening. The biggest threats are for the northern, central and western parts of the state. Meanwhile, the sweltering heat wave that has pummeled New Jersey will continue Sunday. The entire state will remain under a heat advisory, w…