Multiple rounds of severe thunderstorms Monday have already knocked out power to thousands of New Jersey homes and businesses and weather forecasters say more nasty storms are likely on the way through the evening. The National Weather Service has issued a severe thunderstorm watch for 16 of New Jersey’s 21 counties through 9 p.m. Heavy rain, gusty winds up to 65 mph and hail are expected. Tornadoes are also a possibility. The severe weather that started Monday morning sent big Memorial Day crowds home from the Jersey Shore early and caused massive traffic jams on the Garden State Parkway and …