ATLANTA (AP) — Scorching heat was spreading Friday across much of the South, where temperatures are expected to soar over 100 degrees.

The National Weather Service posted heat advisories and warnings from the New Mexico-Texas border eastward to parts of Alabama.

Texas, Oklahoma, Arkansas, Louisiana and Mississippi and west Tennessee were all under heat advisories or warnings Friday morning.

Highs Friday were expected to be 109 degrees in the Dallas and Oklahoma City metro areas; 111 degrees in parts of western Oklahoma; and 100 degrees in Shreveport, Louisiana.

The hot temperatures will combine with high humidity, which could be lethal to some people, forecasters said. They were warning that children, older people, those without air conditioning and outdoor workers will be particularly at risk.

There was also a threat of severe storms, which could spawn tornadoes in parts of the South.

The area at greatest risk of severe storms Friday includes parts of Tennessee, Kentucky, Indiana and Ohio, according to the national Storm Prediction Center in Norman, Oklahoma. That region under the highest severe weather threat includes 5.7 million people and includes the cities of Nashville, Tennessee; Cincinnati, Ohio; and Louisville, Kentucky.