I thought the stormy weather fitted right in with the story of the Mongol invasion of Japan being thwarted by the “kami-kaze” (divine wind) which some say Nichiren had invoked.
Picture from Wikipedia:
Mongol Invasion (Japanese: Mooko shuurai), by Kikuchi Yoosai, 1847. Ink and water colors on paper. Tokyo National Museum. Shows the destruction of the Mongol fleet in a typhoon