Tropical systems can form in several days or just one day. The water temperature needs to be at least 80 degrees in the top 150 feet of the ocean. Winds in the atmosphere must not change too much in direction and speed otherwise a storm would be shredded apart. As warm ocean water evaporates and condenses to form clouds, heat feeds the developing thunderstorms. The thunderstorms act together as they circulate to form a tropical storm. [Source: WKRG (Mobile, Alabama)]