Tropical Storms

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Tropical Storms
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Other Names

• Otherwise known as hurricanes, cyclones,
  typhoons, and wily willies (the Australian
  name!).
• These are very intense areas of very low
  pressure, approximately 500 to 1000 kilometres in
  diameter.
• Tropical storms form over water that is above
  26.5C in temperature.
• The warm water heats the air above it, causing it
  to rise rapidly.
• Cooler air from elsewhere rapidly moves in to
  replace the rising air and the process starts
  again.

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How Do They Occur?

• The rapidly rising moist air, cools as it ascends
  and forms tall cumulo-nimbus clouds.
• These slowly spin around the central point.
• Jet streams above the storm clouds continue to
  suck the air up.
• Cooling air sinks down through the spiralling
  mass of clouds to produce a central eye of the
  storm.
• Tropical storms move quickly over water, as long
  as it is warms enough to keep the storm
  energised.
• Once over land, where there is less moisture and
  the surface is cooler, tropical storms quickly
  calm down.

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Formation

• As the storm approached there would be a drop in
  temperature and pressure.
• Wind speeds would begin to increase and clouds
  would form.
• As the storm is overhead the pressure would fall
  rapidly, as would the temperature.
• Wind speeds would be in excess of 150km/hr and
  the rain would be torrential.
• The wind would whip up waves that could swamp
  entire coastal areas, or drown entire coral
  islands in the Pacific.

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Formation

• The eye of the storm is overhead.
• Skies are clear, the temperature and pressure
  increase, and the wind dies down.
• Unfortunately this is only a brief lull in the
  storm.
• The storm hits again.
• Temperature and pressure falls.
• Torrential rain and wind speeds of over 100km/hr
  occur.
• The winds are now coming form the opposite
  direction than they were before.
• After the storm the temperature and pressure rise
  again.
• The rain becomes showers, and the winds die down.
  
• The clean up operation begins!