Tropical Cyclone Formation

• Warm, moist air rises, leaving an area of low pressure below. Causing warm air from surroundings to move into this low pressure area and rise too.

  
• When the warm air rises, it eventually cools. This moist air will then condense and form large thunderstorm clouds.

  
• The whole system is spinning due to the Coriolis effect. In the southern hemisphere, the storms spin clockwise; in the northern, anticlockwise.

  
• The constant additions of energy from the warm air causes the storm to spin faster and generate higher wind speeds. At 75 mph the storm can be classed as a category 1 tropical cyclone.

  
• The storm develops an eye. This area has extremely low pressure where cool, dry air descends. The weather within the eye is relatively calm and cloud free.

  
• The eyewall, the most intense and powerful area of the storm. Warm, moist air rapidly rises here, with extremely high winds and torrential rain.
• When the tropical cyclone reaches a coast, the low pressure and high winds will cause a large amount of sea water to be pushed onto the coast, (storm surge)

   

  When the storm reaches land, it no longer has a supply of energy (warm, moist air from the sea) and the eye eventually collapses and the storm dissipates. Heavy rain can persist for days.