<Tr> <Td> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> <P> A tropical cyclone is a rapidly rotating storm system characterized by a low - pressure center, a closed low - level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain . Depending on its location and strength, a tropical cyclone is referred to by different names, including hurricane (/ ˈhʌrɪkən, - keɪn /), typhoon (/ taɪˈfuːn /), tropical storm, cyclonic storm, tropical depression, and simply cyclone . A hurricane is a tropical cyclone that occurs in the Atlantic Ocean and northeastern Pacific Ocean, and a typhoon occurs in the northwestern Pacific Ocean; while in the south Pacific or Indian Ocean, comparable storms are referred to simply as "tropical cyclones" or "severe cyclonic storms". </P> <P> "Tropical" refers to the geographical origin of these systems, which form almost exclusively over tropical seas . "Cyclone" refers to their winds moving in a circle, whirling round their central clear eye, with their winds blowing counterclockwise in the Northern Hemisphere and blowing clockwise in the Southern Hemisphere . The opposite direction of circulation is due to the Coriolis effect . Tropical cyclones typically form over large bodies of relatively warm water . They derive their energy through the evaporation of water from the ocean surface, which ultimately recondenses into clouds and rain when moist air rises and cools to saturation . This energy source differs from that of mid-latitude cyclonic storms, such as nor'easters and European windstorms, which are fueled primarily by horizontal temperature contrasts . Tropical cyclones are typically between 100 and 2,000 km (62 and 1,243 mi) in diameter . </P>

What stage does a hurricane get its name