Surface analysis shows a low centered over central Indiana... with substantial pressure falls due to warm air advection and deepening system aloft. Widespread rain and storms will continue ahead of the slow moving cold front and north of a diffuse warm front.
Modified model soundings for current surface conditions indicate a stable surface layer generally north of the Ohio River, but warmer temperatures with 70s existed farther south along an axis from central Kentucky to Mississippi.
Marginal instability, but very strong shear profiles will remain overnight ahead of the cold front now from southern Indiana into western Tennessee. With the warmer temperatures generally south of the Ohio River... some storms may be capable of transporting downward momentum resulting in strong to severe wind gusts. Any tornado threat appears to be maximized now in proximity to the deepening low and should generally wane with time. If storms over Tennessee, Kentucky & Ohio can persist overnight and develop better structure, such as bows... a WATCH may be considered.