Tropical cyclone

A tropical cyclone is a local pressure and wind feature. It originates from the sea along a front. Tropical cyclones are called typhoons in the China sea, hurricanes in the Caribbean sea, in India and South Pacific they are known as cyclones.

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A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure centre, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain.

The winds in the tropical cyclone blow spirally, it has two segments each called a vortex where the wind blow spirally upwards. These are the front and the rear vortexes with a low pressure at the centre of the eye.

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Tropical cyclones are just like a big engine that require warm, moist air as fuel. That is the reason they originate only over warm ocean waters close to the equator. The tropical cyclone occurs mostly between 5° and 20° latitude both in the northern and southern hemisphere.

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The spiral winds are faster, reaching 300-400 km per hour. The associated lightning, thunder and heavy downpour make them infinitely more destructive than other wind features. Their effects are more concentrated and their damage to life and property almost total.

The entire feature moves in a westerly or northwesterly direction in the northern hemisphere, and southwesterly in the southern hemisphere. This effect is due to earth rotation on its axis.

When a tropical cyclone passes over a place, the place first experiences hot calm humid weather followed by strong violent spiral winds and thunderstorms when it is directly under the first vortex. When the eye passes across the place, the weather becomes calm, but the thunderstorm returns when the second vortex crosses, followed by hot humid calm weather at the rear of the cyclone. This is the way tropical cyclone influence a weather of a place.

Tropical usually weakens when they make land fall, because they no longer enjoy the energy from the warm waters. They however move far inland causing damages before they die out. About 15% of global tropical cyclone activity occur in the atlantic region. They also occur in various parts of the pacific affecting south-east Asia, north-east Australia, Mexico and south pacific islands. Those that originate in the Indian Ocean can affect, Bangladesh, India, north-west Austrailia, some part of Africa.

Reference
https://spaceplace.nasa.gov/hurricanes/en/
https://en.wikipedia.org/wiki/Tropical_cyclone
https://www.metoffice.gov.uk/weather/tropicalcyclone/facts
http://www.physicalgeography.net/fundamentals/7u.html