As the main trough dug in from the west, the low became a "cut-off" low, tearing away from the main branch of the jetstream. With extremely strong speed maxes wrapping around the low consecutive days (up to 80/90kst in some areas), outbreaks of supercells and tornadoes occurred, and largely in the same areas, because the origin of the energy (cut-off low) didn't move.
In a typical scenario, the same thing happnes except the trough stays with the jet, does its thing, and then kicks back out with the main jet....however last weekend, we had what I call a "pinwheel" powder keg, where the energy separated itself and just wrecked the same areas all weekend.
I'm sure someone with schooling can better explain all this.