<P> On rare occasions, tropical - like systems, that can reach the intensity of hurricanes, occur over the Mediterranean Sea . Such a phenomenon is called a Medicane (mediterranean - hurricane). Although the geographical dimensions of tropical oceans and the Mediterranean Sea are clearly different, the precursor mechanisms of these perturbations, based on the air - sea thermodynamic imbalance, are similar . Their origins are typically non-tropical, and develop over open waters under strong, initially cold - core cyclones, similar to subtropical cyclones or anomalous tropical cyclones in the Atlantic Basin, like Karl (1980), Vince (2005), Grace (2009) or Chris (2012). Sea surface temperatures in late - August and early - September are quite high over the basin (24 / 28 ° C or 75 / 82 ° F), though research indicates water temperatures of 20 ° C (68 ° F) are normally required for development . </P> <P> Meteorological literature document that such systems occurred in September 1947, September 1969, January 1982, September 1983, January 1995, October 1996, September 2006, November 2011 and November 2014 . The 1995 system developed a well - defined eye, and a ship recorded 85 mph (140 km / h) winds, along with an atmospheric pressure of 975 mbar . Although it had the structure of a tropical cyclone, it occurred over 61 ° F (16 ° C) water temperatures, suggesting it could have been a polar low . </P> <P> Within the Southern Hemisphere tropical cyclones generally form on a regular basis between the African coast and the middle of the South Pacific . Tropical and Subtropical Cyclones have also been noted occurring in the Southern Atlantic Ocean at times . For various reasons including where tropical cyclones form, there are several different ways to split the area between the American and African coasts . For instance the World Meteorological Organization define three different basins for the tracking and warning of tropical cyclones . These are the South - West Indian Ocean between the African Coast and 90 ° E, the Australian region between 90 ° E and 160 ° E and the South Pacific between 160 ° E and 120 ° W . The United States Joint Typhoon Warning Center also monitors the whole region, but splits it at 135 ° E into the South Pacific and the Southern Indian Ocean . </P> <P> The South - West Indian Ocean is located within the Southern Hemisphere between the Africa's east coast and 90 ° E and is primarily monitored by the Meteo France's La Reunion RSMC, while the Mauritian, Australian Indonesian, and Malagasy weather services also monitor parts of it . Until the start of the 1985--86 tropical cyclone season the basin only extended to 80 ° E, with the 10 degrees between 80 and 90E considered to be a part of the Australian region . On average about 9 cyclones per develop into tropical storms, while 5 of those go on to become tropical cyclones that are equivalent to a hurricane or a typhoon . The tropical cyclones that form in this area can affect some of the various Indian Ocean island nations and or various countries along Africa's east coast . </P>

Where do cyclones occur in the southern hemisphere