The low that has moved off to the east is really easy to see, and fairly well defined at 850 mb. Winds out of the North, Northeast, with very slight cold air advection.
The by-hand temp adv values at 12Z = -28.126 at 18Z= -4.49 so very light cold air advection as mid-day approaches.
After 6 hours... heights have increased as the low continues to move of to the east and the higher pressure from Canada is moving in... some rotation in the winds can be seen. Omega values at 700 mb at this same time are positive over all of IN and most of IL