The National Weather Service says: “Life threatening excessive heat will develop across portions of the Midwest” and Georgia will experience “dangerous heat.” There are also warnings or watches in the Southwest, and parts of Colorado, Nebraska, Nevada and Oklahoma.
The majority of Ohio has been under an excessive heat warning and about a dozen cities are among those that could set temperature records, according to the weather service. A spokesperson for electric company AEP Ohio told CNN that some customers should prepare for outages to last until Thursday.
Columbus Mayor Andrew Ginther called on residents to use cooling centers and swimming pools on Wednesday to beat the heat, and to check on neighbors as power slowly comes back online.
Schools have been forced to alter schedules due to the excessive heat. In Wisconsin, where a heat index of 108 degrees Fahrenheit was recorded by the weather service Tuesday at Milwaukee Mitchell International Airport, Milwaukee Public Schools officials dismissed students early and said they will do so again Wednesday.
“Young children and persons with certain health conditions are especially vulnerable to heat-related distress,” the district announced on its website. “For the safety of all, the district has decided to shorten the school day.”
More than a dozen schools in Minnesota that are not fully air-conditioned moved to e-learning on Tuesday, according to Minneapolis Public Schools. Detroit Public Schools announced they will close all in-person schools three hours early through Friday due to the extreme heat.
Relief may soon arrive for the Midwest as the heat is forecast to break late Wednesday, with a cold front due to bring cooler temperatures, scattered showers and thunderstorms.
Temperatures will drop to more-average levels as the front moves through Minneapolis on Wednesday afternoon and Chicago by Wednesday overnight. The cold front is forecast to move through Ohio by Thursday.
Still, even with temperatures easing a few degrees, particularly throughout the Upper Midwest, temperatures in much of the region will remain above normal, with areas of record-setting temperatures persisting into the latter part of the week.
On Thursday, temperatures are forecast to climb well above normal for much of the Great Basin, the Rockies and Southwest. An excessive heat warning has also been issued for parts of interior southern California and Arizona, where daytime highs are expected to soar once again well into the triple digits.
Wildfires rage in Arizona, New Mexico
A second fire just a few miles away, the Haywire Fire, has burned roughly 4,000 acres, according to InciWeb, and both fires remain 0% contained.
Firefighters in New Mexico are battling the two largest fires in the state’s history, the Hermits Peak/Calf Canyon Fire just northeast of Santa Fe and the Black Fire in the Gila National Forest. They have burned more than 600,000 acres combined.
“More than 6,200 wildland firefighters and support personnel are assigned to incidents,” the agency said Tuesday.
CNN’s Robert Shackelford, Judson Jones, Theresa Waldrop, Andy Rose and Dave Alsup contributed to this report.