Heat wave expected to spread to north, east

Scorching temperatures brought on by a “heat dome” have taxed the Texas power grid and threaten to bring record highs to the state before they are expected to expand to other parts of the U.S. during the coming week, putting even more people at risk.

“Going forward, that heat is going to expand ... north to Kansas City and the entire state of Oklahoma, into the Mississippi Valley ... to the far western Florida Panhandle and parts of western Alabama,” while remaining over Texas, said Bob Oravec, lead forecaster with the National Weather Service.

Record high temperatures around 110 degrees Fahrenheit (43 degrees Celsius) are forecast in parts of western Texas on Monday, and relief is not expected before the Fourth of July holiday, Oravec said.

Cori Iadonisi, of Dallas, summed up the weather simply: “It’s just too hot here.”

Iadonisi, 40, said she often urges local friends to visit her native Washington state to beat the heat in the summer.

“You can’t go outside,” Iadonisi said of the hot months in Texas. “You can’t go for a walk.”

What is a heat dome?

A heat dome occurs when stationary high pressure with warm air combines with warmer than usual air in the Gulf of Mexico and heat from the sun that is nearly directly overhead, Texas State Climatologist John NielsenGammon said.

“By the time we get into the middle of summer, it’s hard to get the hot air aloft,” said Nielsen-Gammon, a professor at Texas A&M’s College of Atmospheric Sciences. “If it’s going to happen, this is the time of year it will.”

Nielsen-Gammon said July and August don’t have as much sunlight because the sun is retreating from the summer solstice, which was Wednesday.

“One thing that is a little unusual about this heat wave is we had a fairly wet April and May, and usually that extra moisture serves as an air conditioner,” Nielsen-Gammon said. “But the air aloft is so hot that it wasn’t able to prevent the heat wave from occurring and, in fact, added a bit to the humidity.”

High heat continued for a second week after it prompted Texas’ power grid operator, the Electric Reliability Council of Texas, to ask residents last week to voluntarily cut back on power usage because of anticipated record demand on the system.

The National Integrated Heat Health Information System reports more than 46 million people from west Texas and southeastern New Mexico to the western Florida Panhandle are currently under heat alerts.

The NIHHIS is a joint project of the federal Centers for Disease Control and Prevention and the National Oceanic and Atmospheric Administration.