An Extreme Heat Warning covering parts of Missouri and southern Illinois expires at 9 p.m. Sunday, but the broader heat event driving it is not ending so much as relocating, with forecasters pointing to a long-duration stretch of dangerous heat across the south central United States and the Southeast.
The current warning text from the National Weather Service office in St. Louis cites dangerously hot conditions with heat index values up to 109. It covers portions of south central and southwest Illinois, along with central, east central, and southeast Missouri. Earlier versions of the same warning cited values as high as 111. A separate Heat Advisory covering a wider area, including northeast Missouri, cites heat index values up to 105, and the weather service office in Springfield has its own Extreme Heat Warning running until 8 p.m. Sunday for southeast Kansas and much of central, southern, and western Missouri.
