A tropical cyclone is a rotating, organized system of clouds and thunderstorms, with a closed low level circulation that develops over tropical or subtropical waters. A hurricane is a tropical cyclone with sustained winds of more than 119 km/h. The Atlantic tropical cyclone season runs from June 1st up to November 30th.

There are several favorable environmental conditions that must be in place before a tropical cyclone can form. They are:

  • Warm ocean waters (at least 27 °C) throughout a certain depth;
  • An unstable atmosphere;
  • Relatively moist air;
  •  Relatively weak winds in the upper levels of the atmosphere, and
  •  A pre-existing near-surface disturbance, like for example a tropical wave.