Which god is the Shinto deity of storms and the sea?

The Shinto god associated with storms and the sea is Susanoo.

Susanoo-no-Mikoto is one of the central deities in Japan’s major mythological traditions. He is the younger brother of Amaterasu, the sun goddess, and Tsukuyomi, the moon deity. Myths portray him as volatile and destructive, but also as a heroic protector and culture-bringing figure. His storms and unruly behavior are especially prominent in stories about his conflict with Amaterasu.

After being expelled from heaven, Susanoo descended to Izumo and defeated Yamata no Orochi, an eight-headed serpent. From the monster’s tail he recovered the sword Kusanagi, one of the Three Sacred Treasures, and won the hand of Kushinadahime.

Susanoo is not merely a storm god. He is also linked with the sea, agriculture, protection from calamity, disease-averting rites, love, and marriage. Raijin is the thunder god, while Fujin is the wind god; neither is the best answer to this question. Kuraokami is a distinct dragon-like rain and water deity.