The Atlantic hurricane reanalysis in 2013 concluded Coming_to_believe that the storm Catastrophe developed Coming_to_be into a tropical depression Catastrophe on September 9 off the coast of West Africa , but the United States Weather Bureau was unaware that a tropical cyclone Catastrophe existed until September 16 ; by then , it was already a well-developed hurricane Catastrophe and had tracked Self_motion westward toward the Sargasso Sea .