An Atlantic hurricane is a type of tropical cyclone that forms in the Atlantic Ocean primarily between June and November. The terms "hurricane", "typhoon", and "cyclone" can be used interchangeably to describe this weather phenomenon. These storms are rotating, organized systems of clouds and thunderstorms that originate over tropical or subtropical waters and have closed low-level circulation, not to be confused with tornadoes. They form over low pressure systems. In the North Atlantic, central North Pacific, and eastern North Pacific, the term "hurricane" is mainly used, whereas "typhoon" is more commonly used for storms originating in the western North Pacific. The term "cyclone" is used in the South Pacific and Indian Ocean.