Valleys of Ohio and Tennessee into the Appalachians...
As the upper trough continues, there should be some serious threat over portions of the OH/TN Valleys and into the Appalachians on Tuesday. The precise location of the primary surface low and the evolution of the upper trough remain somewhat uncertain, but there is enough confidence in a somewhat narrow corridor over these regions to add a 15% severe area for Tuesday. A cold front approaching eastward should be preceded by rich, low-level moisture.
It appears likely that convection may redevelop and/or intensify by Tuesday afternoon. Given the predicted severity of a low-level jet concentrated over portions of the region, strong deep-layer shear and mild instability should be sufficient for organized severe convection, offering some concern for damaging winds and maybe tornadoes.

Update from the National Weather Service-Louisville office: