I saw a boiw echo move in from the west, the top part had a comma head rotaing westward?

Question

if im looking to the west how would that comma head move in from the west while roting in from the east?

Answer 1

This means that portion of the t'storm has some decent rotation with it and it may be an embedded supercell.  Depending on how low the rotation exists this storm could possible become tornadic if it isn't already.