The Mid-South remains on pace to break all-time records for August heat as we can expect another week of high temperatures near 100. Rain chances this week are minimal although KY could receive some rain as the ridge retreats to the west and Mesoscale Convective Systems (MCS) follow the ridge into the Mid-Atlantic. However, I do think our rain chances improve after the 20th as hurricane season gets going.
Synoptic overview: The massive heat ridge will retreat over the central Plains this week and allow the polar vortex to drop far south of normal over James Bay. This will allow frequent cold fronts to drop out of Canada and produce frequent MCSs along the frontal boundary from the Great Lakes into the Mid-Atlantic. There is a chance that one or more of these MCSs could move into KY (like the one Monday afternoon west of Bowling Green) but the showers/thunderstorms will rapidly weaken as they move into the hot, dry air currently over the state. These MCSs will be around all week but they will be very hit or miss and most places will be dry all week.
The first event that will increase our rain chances will be an area of tropical weather currently over the NW Caribbean that should make landfall over TX midweek (probably as a weak tropical storm or depression). There is a good chance that the moisture from this storm will eventually get entrained into one of the cold fronts (discussed above) over the weekend and bring a wider coverage of rain for KY. The second event to watch will be the hurricane that should form from what is now TD 4 over the eastern Atlantic. Computer models show that this storm will move into the Gulf of Mexico after the 20th. Where it will eventually make landfall is unknown, but there is a chance that the moisture from this storm will move over the Mid-South after it makes landfall.