It's important to emphasize that, even when the polar vortex exhibits one of its wild moves, it's really difficult to tie the polar vortex to specific weather events. We can say that changes in the shape or strength of the polar vortex might make certain weather patterns more likely, but it's hard to go beyond more probabilistic statements to attribution statements because there is so much that can affect how specific storms unfold. Here it's not clear exactly which weather you are referring to (maybe the Dec 9 Tennessee tornado outbreaks?) but this sort of weather can be even trickier because many things go into creating atmospheric conditions for tornadoes to occur and the polar vortex has no direct influence on most, if any, of those conditions. Could polar vortex variations be related in a probabilistic sense to wintertime tornadic outbreaks? Maybe, but more research needs to be done to understand these connections.