Check out these reflectivity and absolute velocity images of a textbook supercell south of Santa Rosa at 5:23 pm local time in Argentina!  I would not be surprised if this supercell had a tornado on the ground at the time of this image given the couplet in velocity, and at the very least baseball or larger hail.  These images were provided by Romina Mezher of INTA!  She has been talking with Matias and Ramiro while they have been chasing in the field today, and they reported rotation north of Santa Rosa but no tornadoes as of yet.  Incredible radar presentations though...