The hottest days of summer are yet to come, with today and tomorrow being just the start. A ridge of high pressure has locked itself into the eastern half of the nation, and many are feeling its hot and humid effects. It's 91° at Louisville International Airport, 88° in the southeastern suburbs of Louisville, 91° in Bowling Green, KY, and 95° in Jackson, TN as of 3pm EDT/2pm CDT. Doesn't take me to tell you that those are some hot readings! Areas near the Louisville area have been placed under a Heat Advisory until 8pm tomorrow while areas to the west of Owensboro have been placed under a more strongly-worded Excessive Heat Warning. Highs in Louisville could reach near 96° tomorrow with heat indices ("feels like" temperatures) up to 110.
Most of West Tennessee is under an Excessive Heat Warning until tomorrow at 10pm. Jackson could get up to 100 tomorrow with Memphis easily passing into the triple digits. Heat indices near or above 110 are expected, so limit your time outside if possible and drink lots of water.
As a trough and associated "cool" front dip down from the north, we should see chances for storms enter the forecast by Tuesday, which will help to break the heat a bit. While more scattered in Tennessee, Kentucky will likely see a good helping of storms during Tuesday afternoon and evening, some of which may be strong. The Storm Prediction Center has placed portions of Kentucky (including the Louisville area) under a Slight Risk for severe storms. I don't think there will be much, if any, of a tornado and hail threat from these, but gusty winds could present some issues across the region.