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We see tropical cyclones (going by different names e.g. hurricane, typhoon, cyclone) all over the tropics, but it seems that there are never any storms in the southern Atlantic. See this map of tropical cyclone activity and note the lack of activity in the south Atlantic and also in the south Pacific until you near Australia.

tropical cyclone map
source

Where are all the tropical cyclones in the southern Atlantic basin?

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    $\begingroup$ @Michael this isn't a dupe of that Q. That Q is about a storm transiting the equator and this question is about storm genesis south of the equator (specifically in the Atlantic) $\endgroup$ – casey Nov 13 '14 at 18:20
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    $\begingroup$ wral.com/weather/blogpost/1672862 $\endgroup$ – DavePhD Nov 13 '14 at 18:45
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    $\begingroup$ @Richard - the diagram is not completely factually correct. The Arabian Sea does occasionally experience tropical cyclones. There have been two this year already-Nanauk and Nilofer. $\endgroup$ – gansub Nov 14 '14 at 3:22
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    $\begingroup$ A reference for the diagram? $\endgroup$ – arkaia Nov 14 '14 at 4:20
  • $\begingroup$ @Richard. The lower land mass in the southern hemisphere does not help as well as compared to the northern hemisphere. I am sure cyclones do form but maybe over the ocean mostly and quickly dissipate. $\endgroup$ – gansub Nov 15 '14 at 2:41
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There have been tropical storms and hurricanes in the south Atlantic, with, according to NOAA's webpage Subject: G6) Why doesn't the South Atlantic Ocean experience tropical cyclones?, with a hurricane forming in the south Atlantic making landfall in Brazil in 2004 and a strong tropical depression/weak tropical storm that formed off the coast of Congo in 1991 - but these are exceedingly rare.

The reason why these storms generally don't occur in the south Atlantic, according to the Penn State webpage Upper-level Lows as being:

There are two primary reasons why tropical cyclones are rare in the south Atlantic basin. First, vertical wind shear between 850 mb and 200 mb is typically greater than 10 meters per second (check out the long-term average of vertical wind shear between 850 mb and 200 mb). To make matters worse, westerly shear dominates over latitudes where tropical cyclones would be most likely to form. Second, easterly waves from Africa do not form south of the equator (the MLAEJ is a northern hemispheric singularity.

Further, from the NASA News page The Nameless Hurricane, they provide an extension to the explanation with

Vertical wind shears in the south Atlantic are too strong for hurricanes," Hood explains. Winds in the upper troposphere (about 10 km high) are 20+ mph faster than winds at the ocean surface. This difference, or shear, rips storms apart before they intensify too much

An article The first South Atlantic hurricane: Unprecedented blocking, low shear and climate change (Pezza and Simmonds, 2005) suggest that the implications of the southern hemisphere hurricane presents

evidence to suggest that Catarina could be linked to climate change in the SH circulation, and other possible future South Atlantic hurricanes could be more likely to occur under global warming conditions.

Catarina refers to the southern hemisphere hurricane

SH = Southern Hemisphere

edited to add an NASA Earth Observatory satellite image of the hurricane:

enter image description here

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    $\begingroup$ @Omen - could you explain how westerly shear prevents formation of tropical cyclone or is that a separate question ? $\endgroup$ – gansub Nov 14 '14 at 3:20
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    $\begingroup$ @gansub that could be a very nice separate question. $\endgroup$ – user889 Nov 14 '14 at 3:21
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    $\begingroup$ +1. Upper level shear is one of the main enemies of tropical cyclone formation and strengthening. Coming from an area subject to hurricanes, I love it when the weather forecast says that there's a lot of shear in the Atlantic, Caribbean, or Gulf of Mexico. It means I can breathe a bit more easily. $\endgroup$ – David Hammen Nov 14 '14 at 7:25
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The original question asked why there were no hurricanes in the southern hemisphere. The answer given:

It really is just a naming convention based on location. You can see in the wikipedia article here: http://en.wikipedia.org/wiki/Tropical_cyclone#Classifications.2C_terminology.2C_and_naming , it says:

Tropical cyclones are classified into three main groups, based on intensity: tropical depressions, tropical storms, and a third group of more intense storms, whose name depends on the region. For example, if a tropical storm in the Northwestern Pacific reaches hurricane-strength winds on the Beaufort scale, it is referred to as a typhoon; if a tropical storm passes the same benchmark in the Northeast Pacific Basin, or in the North Atlantic, it is called a hurricane. Neither "hurricane" nor "typhoon" is used in either the Southern Hemisphere or the Indian Ocean. In these basins, storms of a tropical nature are referred to as either tropical cyclones, severe tropical cyclones or very intense tropical cyclones.

... each basin uses a separate system of terminology, which can make comparisons between different basins difficult. In the Pacific Ocean, hurricanes from the Central North Pacific sometimes cross the 180th meridian into the Northwest Pacific, becoming typhoons (such as Hurricane/Typhoon Ioke in 2006); on rare occasions, the reverse will occur.

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    $\begingroup$ OK. Then you can reformulate the quest as "Why are there no tropical cyclones in the southern atlantic basin?", if you prefer. $\endgroup$ – Richard Nov 13 '14 at 17:45
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    $\begingroup$ Note that the Q has been edited to avoid the naming convention issues and this A no longer answers the Q. $\endgroup$ – casey Nov 13 '14 at 18:21
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    $\begingroup$ @casey yes it's really a different question now. $\endgroup$ – farrenthorpe Nov 13 '14 at 18:48

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