4.) Ocean waters are not a uniform temperature from the surface to the ocean floor, and the world's currents are not simple circles going round and round, but from a simplistic standpoint the surface water off the U.S. East Coast is a lot warmer than the West Coast, which is the primary reasons hurricanes hit Florida
5.) The Hawaiian Islands were formed by such a hot spot occurring in the middle of the Pacific Plate. While the hot spot itself is fixed, the plate is moving. So, as the plate moved over the hot spot, the string of islands that make up the Hawaiian Island chain were formed.