ss over the Southeast bringing in warm tropical air from the Gulf of Mexico.

Excessive heat watches and heat advisories are up from the Plains to the Mid-Atlantic and throughout the Southeast. High temperatures and humidity are creating Baghdad-like heat indexes of 110 and above.

"It feels like sticking your head in an oven," said weather service meteorologist Leonard Vaughan of Charleston, S.C., where the heat index was likely to hit 120 degrees Wednesday.

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Atlanta residents sweated through their warmest overnight temperatures Tuesday as the heat dipped only to 82 degrees before dawn Wednesday. Record highs were set in Baltimore; Charlotte; Florence, S.C.; Roanoke, Va.; and Cincinnati.

Electric utilities in Alabama and the Carolinas ramped up output to meet near-record demand from consumers.

In Savannah, Ga., the service department at Byrd Heating and Air Conditioning has been inundated by calls from "crazy people freaking out," said dispatcher Tye Munn, 29. He said technicians are working 18-hour days and two repairmen passed out from the heat.

Business was also hot at Hastings Nature & Garden Center in Atlanta, which marketing director Francesca Battista said is "surprisingly busy" in the usually slow month of August. She said demand is heavy for underground sprinkler systems to water-parched plants.

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The heat has exacerbated a dry spell in the Southeast. All but six of North Carolina's 100 counties are in a drought, with 27 suffering extreme or severe conditions. In Robeson County, N.C., on the South Carolina border, an Easter freeze and August heat have "devastated" the corn crop. Farmers may be forced to sell off livestock because they don't have enough hay for feed through the winter, said extension service field crops agent Kent Wooten. He said the county's crop income, usually about $80 million, could be slashed by half. "It's the worst that just about anybody can remember," he said.

The heat also closed some early-opening school systems. Students who started classes in Dayton, Ohio, on Monday were told to stay home Wednesday and today because of an excessive heat warning.

In Springfield, Mo., city buses offered free rides to public cooling shelters, and local YMCAs for the first time invited the public to cool off in their indoor pools at no charge.

Not everyone could head indoors, though. At the PGA Championship, in Tulsa, at least 11 spectators were treated for heat-related illnesses during practice rounds of the golf tournament. Officials bent course rules to allow onlookers to bring their own bottled water and ordered 21 giant power fans to blow air on the greens.

The weather wasn't much better for water creatures. About 70 miles west of Omaha in Surprise, Neb., where the Big Blue River overflowed its banks after 4 inches of rain fell in an hour, fish were seen swimming on a flooded state highway.

Contributing: Doyle Rice; Wes Johnson, Springfield (Mo.) News-Leader; Associated Press