In Illinois we used to call that an Alberta Clipper!
The Alberta Clipper and the polar vortex are two totally separate weather patterns. The clipper is more of a meso-scale feature...which means its over an area less than 1000km wide....and its fast moving. The polar vortex is a synoptic scale pattern....which means it is on the continental scale...and it can sit and spin for days.
Went skiing near Calgary a while back. Arrived at -40 deg.
When it got to -20F. they opened the lifts.