How do you avoid TRS ? why less TRS in southern hemisphere ?

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Summary of observations and actions to avoid TRS

In North Hemisphere
Observation - Wind veering means vl in Dangerous semi-circle
Action - Wind 1-4 pts on stbd bow. Alter course to starboard as wind veers

In South Hemisphere
Observation - Wind backing- means vl in Dangerous semi-circle
Action - Wind 1-4 pts on port bow. Alter course to port as wind backs

Fast ship - Wind 1 pt on bow
Slow ship - Wind 4 pts on bow


Why less TRS in Southern Hemisphere ?  
In general twice as many hurricanes form in the Northern Hemisphere than in the Southern Hemisphere.

The reason why more hurricanes form in the Northern Hemisphere is that the conditions favorable to hurricane development are more prevalent in the Northern Hemisphere than the Southern Hemisphere. These conditions include: warm ocean water and low wind shear. In the Southern Hemisphere Ocean temperatures are cooler and there is greater winds and hence wind shear that prevent formation of the cyclone.

The Southern Hemisphere oceans are cooler mainly because there is more ocean to warm in the Southern Hemisphere and partly due to the large Antarctic Ice Sheet in the south. Ocean water takes a lot more energy to heat than does the land surface. There is much more land is in the Northern Hemisphere than the Southern Hemisphere.

The winds are stronger in the South because the Northern Hemisphere is generally warmer; the larger temperature change with distance (or temperature gradient) causes winds to be stronger. The stronger winds cause what is known as wind shear that prevents the development of the cyclone.  Thus wind shear is produced as winds blow preventing a tropical cyclone from developing.


Hurricanes need 3 main ingredients in order to form: warm ocean water, low air pressure, and low wind shear. These ingredients are readily available in the tropical waters of the northern hemisphere, especially in the warm, shallow Caribbean Ocean and Gulf of Mexico, as well as the central Pacific Ocean. These ingredients are more rare in the southern hemisphere. The Atlantic Ocean, for example, is much colder in the southern hemisphere. There is also more wind shear, which tends to tear storms apart before they can get organized into a hurricane.


Why no TRS in southern atlantic?
TRS can develop only when the ITCZ gets far enough from the equator to allow significant Coriolis rotation. Because the ITCZ is almost always north of the equator in the Atlantic, TRS are rarely observed in the South Atlantic.
(In March of 2004, the first South Atlantic tropical cyclone Catarina on record occurred. It struck Brazil and caused considerable damage. Some scientists suggest that global warming may result in more frequent South Atlantic cyclones in the future.)