A cyclone is an area of closed, circular fluid motion rotating in the same direction as the Earth. This is usually characterized by inward spiraling winds that rotate counter-clockwise
The main source of energy for tropical cyclones is the warm oceans in the tropical regions. To initiate a tropical cyclone the sea-surface temperature generally needs to be above 26.5°C.
The development of a tropical cyclone also relies on favorable broad-scale wind regimes and can persist for several days with many following quite erratic paths.
As the air moves toward the center of the disturbance, it “curves” or “spirals”, rather than flowing in a straight line.This spiral effect comes from the rotation of the Earth – as air moves over large distances, the Earth moves underneath it, producing a spiral effect.
When the winds in the rotating storm reach 39 mph (63 kmph), the storm is called a “tropical storm”. And when the wind speeds reach 74 mph (119 kmph), the storm is officially a “tropical cyclone” or hurricane. Tropical cyclones usually weaken when they hit land, because they are no longer being “fed” by the energy from the warm ocean waters. However, they often move far inland, dumping many centimeters of rain and causing lots of wind damage before they die out completely.