The work week will start off hot with high temperatures likely to be at or just a little above the warmest values seen so far this summer. Regardless of the actual temperature, the humidity is expected to make the heat oppressive. Heat indices this afternoon over southwest Indiana and west central Kentucky likely will rise to around 110 degrees for several hours. Just east of that area, along the I-65 corridor, heat indices will rise to the 103-108 degree range. For the Bluegrass and Lake Cumberland regions, the heat will be a little less oppressive, but still heat indices will max out into the lower 100 degree range. Below is a map of the Excessive Heat Warning and Heat Advisory in effect today, as well as the max heat index values for this afternoon:
This excessive heat is caused by an upper level high pressure system drifting into the region today and into Tuesday. The colors in the background of the image below are indicative of the widespread heat across most of the county today and Tuesday. The red/white colors are hot, whereas the yellows and greens are cooler. The contours represent the weather conditions roughly 20,000 feet up in the atmosphere. Higher values are indicative of stable areas, usually hot and dry.
Some heat will continue to plague the area Tuesday, but the ridge of high pressure, indicated by those contours, will shift south of the region. The continued moist atmosphere combined with weaker storm suppression will bring scattered storms to the region Tuesday afternoon that should help to slightly cool things down by late afternoon.