The NWS said the heaviest rain could produce rainfall rates of more than an inch per hour, with flooding possible in low-lying areas, places with poor drainage and along small streams. Some storms could also produce damaging wind gusts, the weather service said. Heavy rain and thunderstorms are expected to continue across the New York City region Monday, raising the risk of localized flash flooding , the National Weather Service said. The Weather Prediction Center placed the region under a slight risk for excessive rainfall, meaning scattered flash flooding is possible. Flood Watches were also put into effect through Monday evening for much of northeastern and central New Jersey, where the National Weather Service said excessive rainfall could cause flooding.