What is the lightning capital of America?

Without a doubt, Florida. There are very good meteorological reasons for this: it is close to the tropics (which have prodigious amounts of warm moist air masses), and ocean water literally surrounds it. In fact, Cape Kennedy spaceport has a huge problem with the statistical likelihood of lightning damaging space vehicles and support equipment. So-called 'anvil forecasting' is essential to space launch safety, and there has only been limited research in this area. A lightning hit to a rocket during launch phase can easily destroy it. Because liquid fuel loaded into sitting space vehicles must be pumped back out, it costs a large amount to scrub a launch. Better long term forecasting of convective storms (i.e. thunderstorms) would help improve launch planning.