...Heat and Humidity Returns Today... Oppressive humidity levels will return to the western half of the region today. In combination with temperatures reaching the lower to mid 90s, heat index values will reach 100 to 105 during the afternoon hours across southeast Missouri, parts of southern Illinois, and far western Kentucky. Somewhat lower heat index values in the mid to upper 90s are forecast across southwest Indiana and the Pennyrile region of western Kentucky. An extended period of heat and humidity is in store Thursday through early next week, with daily heat index readings topping out in the 100 to 105 range. Please use caution if spending time outdoors, limit strenuous activity to early or late in the day, drink plenty of water, and take frequent breaks.