The heat index – what the body feels – will range from 100 to 115 degrees across large portions of the central and southern Plains as well as into the lower Mississippi Valley. Oklahoma City is expecting a record high of 106, the weather service said. On Wednesday, 100-degree heat will spread northward into Oklahoma and Kansas, as well as eastward into Arkansas and Louisiana. Del Rio hit 110 degrees, marking its 10th consecutive day of record highs. Several daily high temperature records were broken or tied Tuesday in Texas, including at Houston Hobby Airport, Corpus Christi, Laredo and Del Rio. The National Weather Service in Memphis warned the warm front could bring dangerous peaks of 110 to 115 degrees Thursday and Friday. More than 150 heat records could be broken during the next six days. The heat wave that has impacted Texas for well over a week is set to expand northward and eastward. While the Texas power authority has assured residents the energy supply is sufficient to avoid blackouts, it is asking residents to cut back on power usage where possible. Why we're talking about the Texas power grid again (Yffy Yossifor/Fort Worth Star-Telegram/Tribune News Service via Getty Images) Yffy Yossifor/Fort Worth Star-Telegram/TNS/Getty Images

Power lines out of the Handley Generating Station along Rosedale Street in Fort Worth.

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