Much of the Central U.S. is bracing for a scorching heat wave, with triple-digit temperatures expected to persist through Tuesday. This extreme heat poses significant risks across Missouri, Arkansas, Tennessee, Illinois, and surrounding states. Daytime highs are forecast to reach the upper 90s to near 100°F (32-38°C), while overnight lows will offer little respite, remaining in the upper 70s (around 25°C). The combination of high temperatures and humidity will result in dangerously high heat indices.