Check out these higher resolution radar images of a tornadic supercell in Argentina on November 17,emailed to me by Luciano Vidal, a PhD student in meteorology from the University of Buenos Aires.  He updates this blog that focuses on South American severe weather: http://severestormargentina.blogspot.com/

This supercell clearly exhibited a very strong couplet on radar with a classic hook echo.  I bet this storm had a photogenic tornado with baseball or larger hail at the time of this image!

Images courtesy of the National Institute of Agricultural Technology (NITA)