<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>
<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>
where does the energy for hurricanes originate from
where does the energy for hurricanes originate from
the evaporation of water from the ocean surface , which ultimately recondenses into clouds and rain when moist air rises and cools to saturation
the evaporation of water from the ocean surface , which ultimately recondenses into clouds and rain when moist air rises and cools to saturation