During the daytime on Tuesday 15 March 2011 at 1820 UTC the TRMM satellite flew over a rare cyclone labeled ARANI in the south Atlantic Ocean. ARANI has the appearance of a tropical cyclone but has been classified as a subtropical cyclone. NOAA's Satellite and Information Service classified ARANI as a T1 on the Dvorak intensity scale which would indicate an estimated wind speed of about 29 kts (~33 mph). TRMM's Microwave Imager (TMI) and Precipitation Radar (PR) data were used in the image on the right to show rainfall near ARANI.

Tropical cyclones are very rare in the south Atlantic Ocean. In 2004 a cyclone called Catarina formed in the south atlantic and caused some controversy when it was classified as a hurricane by the United States' National Hurricane Center (NHC). Click here to see more about the rare South Atlantic Tropical Cyclone that hit the Brazilian coast on 28 March 2004.