See Steve Babin's comprehensive
site on the supercells that produced the Nashville tornadoes.
Animation
Moving gif (~204k) showing BREF1
reflectivity from OHX [Nashville WSR-88d] during passage of tornadic
supercells over Nashville and Bowling Green). The
animation highlights three supercells in Tennessee and southern
Kentucky.
OHX VAD 1954-2044 UTC
This image shows the vertical wind profile at Nashville
at 4 minute intervals roughly encompassing the time of the passage
of the second supercell over Nashville. The profile is almost
textbook tornadic.