One thing to watch is where the line pivot is. The further north up the line you go, the more the storms are moving NE vs more ENE on the lower end. At some point those cell will start to separate and become more cellular. On the lower end of the pivot, you sometimes can develop a cell with it’s own meso feature. That’s what happened on Wednesday night with the tornado In Chattanooga. Only this time the shear is more favorable. .