Tropical cyclone is a generic term that also includes hurricane and typhoon. Meteorologists define a tropical cyclone as “… a non-frontal low pressure system of synoptic scale developing over warm waters having organized convection and a maximum mean wind speed of 34 knots (70 km h−1) or greater extending more than half-way around near the center and persisting for at least 6 h” (BOM, 2009).
In the Northern Hemisphere, tropical cyclones rotate in an anticlockwise direction. They are referred to as hurricanes (North Atlantic, North East Pacific east of the dateline), or typhoons (Northwest Pacific east of the dateline). In the Southern Hemisphere, they rotate in a clockwise direction, and are called cyclones in the Indian Ocean and the Pacific Ocean west of 160°E, and hurricanes east of 160°E.
Tropical cyclones have a distinctive “eye,” which is usually some tens of kilometers across, and a surrounding cloud mass that is some hundreds of kilometers across. Unlike tornadoes,...