Heat will bear down on Texas and the Great Plains within days, driving temperatures in Dallas above the 38°C mark for the first time this year.
A dome of high pressure will build across the middle of the US, boosting demand for power to run air conditioners, said Jim Rouiller, lead meteorologist at the Energy Weather Group.
The heat will expand eastward later next week into Chicago while a blanket of humidity will make it feel like 38°C from New York to Washington.
For Texans, “next week will be the hottest week they have had all summer long,” Mr Rouiller said. “Cooling demand will be the highest we have seen all summer.”
The state’s grid manager said on Thursday that electricity demand appears likely to break records next week, although he assured residents there will be enough power to go around.
The first day Dallas-Fort Worth usually reaches such temperatures is July 1, but this year, that mark has yet to be reached, said Allison Prater, a National Weather Service meteorologist in Fort Worth. “We are quite a bit behind.”
With humidity, it will feel hotter across Texas through next week, Ms Prater said.
“The worst of the heat so far this summer has been centred in the drought-parched West, where successive waves set all-time records in Oregon, Washington state and even Canada. In the East, New York’s La Guardia Airport and Boston touched [38°C]."
The high pressure will likely be centred over Oklahoma, making conditions particularly brutal from Iowa to Arkansas, Mr Rouiller said. Where the ground is parched from drought, the heat will be worse because more of the sun’s energy is available to bake the air.
“This is the hottest one so far for them — this is the dome of doom,” he said.