The National Weather Service has issued flood warnings in two New Jersey counties because of strong thunderstorms that have dumped heavy rain on some areas of the state Tuesday afternoon. One flash flood warning, issued about 3:45 p.m. Tuesday, is effective through 6:45 p.m. and covers central sections of Middlesex County and northeastern sections of Monmouth County, where up to 2 inches of rain has been reported. Among the locations that could be impacted by flash flooding are Brownville, East Brunswick, Keansburg, Lincroft, Matawan, Middletown, New Brunswick, North Brunswick, Old Bridge, San…