An MCS or Mesoscale Convective System is scheduled to move through Kentucky and Indiana tomorrow morning. An MCS is basically a large cluster of storms that normally has a distinct wind-driven line of strong to severe storms on the east side as it pushes along at a decent speed. Tornadoes can sometimes form in little notches or "eddies" that develop in the strong line of storms on the east or leading side of the MCS. Given that there will be some helicity (turning in the atmosphere) from Indianapolis to Bowling Green, KY as the MCS moves through, it would not surprise me to see a Tornado Warning or two issued since there could be a little rotation aloft. This will not be a tornado event though and I expect the probability of tornadoes to remain low. This will not be an event like Wednesday when we had five tornado touchdowns in the area because we will not have supercells developing. The Louisville area can expect storms to start sometime around 7am and possibly last into the mid afternoon hours. While the initial line of storms in the morning could be strong or severe, heating during the day could intensify storms by around noon. The main threats from this complex of storms will be damaging winds (especially in the morning) and hail. The 12z NAM model run (top left) seems to have a good handle on the storms.
These storms will be driven by a mid-level shortwave trough, which is basically just a ripple or wave in the atmosphere, and a warm front rising northward. Once this warm front passes to our north tomorrow, we can expect temperatures to exceed 90 degrees again next week.
We're under a Slight Risk tomorrow from the Storm Prediction Center (left) and on the very southern edge of another one on Monday (right) since another line of storms may try to come through early in the day:
Be sure to scroll down and read my exhaustive post on the Louisville tornadoes that happened on Wednesday.