What is a heat dome? Scorching Texas temps expected to spread north and east

Persistent heat forced ERCOT to ask Texans to voluntarily conserve power last week

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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 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 are forecast in parts of western Texas on Monday and relief is not expected before the Fourth of July holiday, Oravec said.

In North Texas, NBC 5's team of Weather Experts expects the heat to start to subside over the weekend.

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 Nielsen-Gammon 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."

WHAT IS THE HEAT BLAMED FOR SO FAR?

The heat caused Texas' power grid operator, the Electric Reliability Council of Texas, to ask residents last week to voluntarily cut back on electricity 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.

The heat comes after Sunday storms that killed three people and left more than 100,000 customers without electricity in both Arkansas and Tennessee and tens of thousands powerless in Georgia, Mississippi and Louisiana, according to poweroutage.us.

CLIMATE CHANGE?

In Texas, the average daily high temperatures in Texas have increased by 2.4 degrees - 0.8 degrees per decade - since 1993, according to data from the National Oceanic and Atmospheric Administration amid concerns over human-caused climate change resulting in rising temperatures.

Earlier this month, Multnomah County, Oregon, filed a $1.5 billion lawsuit against more than a dozen large fossil fuel companies to recover costs related to extreme weather events linked to climate change.

The lawsuit, first reported by The Oregonian/OregonLive, alleges the combined carbon pollution the companies emitted was a substantial factor in causing and exacerbating a 2021 heat dome that killed 69 people.

An attorney for Chevron Corp., Theodore J. Boutrous, Jr., said in a statement that the lawsuit makes "novel, baseless claims."


HEAT SAFETY TIPS

With heat like this, you'll want to take precautions and be prepared.

Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors to ensure they stay cool.

Young children and pets should never be left unattended in vehicles. According to the National Safety Council, if it's 95 degrees outside a car's internal temperature could climb to 129 degrees in 30 minutes. After just 10 minutes, temperatures inside could reach 114 degrees.

A child's body temperature heats up three to five times faster than an adult's, and heatstroke can begin when a person's core body temperature reaches 104 degrees. According to the Texas Department of State Health Services, a core temperature of 107 degrees is lethal.

Take extra precautions if you work or spend time outside. When possible reschedule strenuous activities to early morning or evening. Know the signs and symptoms of heat exhaustion and heatstroke. Wear lightweight and loose-fitting clothing when possible. The Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air-conditioned environments to reduce risk during outdoor work. Anyone overcome by heat should be moved to a cool and shaded location. Heatstroke is an emergency! Call 911. The CDC has more information on heat-related illnesses.

Take care of your pets by providing fresh, cool water and shade. Also, pets should not be left outside and unattended for too long. It's too hot and they need to be brought inside.

Copyright AP - Associated Press
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