Record or near-record October heat is forecast across parts of the central and eastern United States early this week, followed by a sharp cooldown over the weekend.

A broad area of high pressure is pushing warm, humid air north. Temperatures are expected to reach the upper 80s and 90s in the Midwest and the mid- to upper 90s in the Southern Plains, Mid-South and Southeast. In parts of the South, humidity could push the heat index above 100 degrees.

Forecasters expect hundreds of daily high-temperature records to be tied or broken through Wednesday. St. Louis, Chicago, Atlanta and Charlotte could see their highest temperatures of the season.

A cold front is expected to move into the South and Southeast late in the workweek and continue through the weekend. Temperatures could fall by about 40 degrees from early-week levels, with overnight lows in the 30s and low 40s bringing morning frost back to the Upper Midwest and central Great Plains.