Texas is no stranger to scorching summer heat, but even Texans are growing weary of a large “heat dome” that has parked itself over the region and will send temperatures soaring to potentially deadly extremes across the state for the third week in a row.
Many areas of Texas have experienced days of triple-digit temperatures. On Sunday, the National Weather Service (NWS) office for Austin and San Antonio said in a tweet that the city of Del Rio, Tex., on the border with Mexico, had seen eight consecutive days of record daily highs, all in the triple digits. In central Texas, San Angelo hit 112 degrees Fahrenheit on Sunday, far surpassing that date’s previous record of 106 degrees F set in 1994. now it’s just another 110° heat day to add to the count,” the The NWS San Angelo office wrote on Twitter. (The city set a record high of 114 degrees F the previous week.)
This relentless, record-breaking heat wave bears all the hallmarks of what scientists expect to see with climate change: namely, heat events that are more intense, longer lasting and more frequent.
��️��️Here’s another way to say, “It’s been hot.” We’ve had excessive heat warnings for two weeks in a row! We’ve broken several high temperature records and had incredibly high dew point readings. �� #txwx #stxwx #It’s hot pic.twitter.com/rfm4rPkfBO
— NWS Corpus Christi (@NWSCorpus) June 26, 2023
The stifling temperatures baking Texas and Mexico since early June are the result of a high-pressure system — known as a ridge — that has “become entrenched and really hasn’t changed much,” said Andrew Quigley, a meteorologist. at the NWS office for Austin and San Antonio. High pressure systems have sinking air, which compresses and heats up. These systems also bring clear skies, bringing in plenty of sunlight that further raises surface temperatures. When such a system becomes trapped over an area, it is referred to as a “heat dome”. Another heat dome developed over the Pacific Northwest and Canada in late spring, fueling wildfires that have sent smoke across much of the US
So why is the current heat wave in Texas dragging on for so long? Once a heat dome has dug in, it takes a good push from the jet stream or other relatively strong system higher up in the atmosphere to dislodge it – and “we have never seen such influences traversing this part of the atmosphere. country,” says Quigley. The latest guidance from forecasting models suggests the heat won’t recede until sometime after the Fourth of July.
And it’s not just the heat, it’s the humidity. Texas’ proximity to the Gulf of Mexico means there’s a lot of moisture in the air, and high humidity raises the heat index (a measure of how temperatures feel to the human body). According to the NWS, many locations have seen record hours of dangerously high heat index readings. A significant portion of Texas has experienced heat indexes in the 110s or 120s F. Corpus Christi, Tex., located on the Gulf of Mexico, saw the heat index reach as high as 125 degrees F. The city also experienced 14 straight days of experienced excessive heat warnings. “We’ve far surpassed the most extreme heat warning days we’ve had in a year,” said Penny Harness, a meteorologist with the NWS Corpus Christi office.
Even in a part of the country that is no stranger to sultry summers, this persistent extreme heat is dangerous, especially for people who work outdoors, such as construction workers and farm workers, but also for those without homes, the very young, the elderly and those with certain medical conditions, such as heart disease and asthma. “It’s dangerous for people because you just don’t have a chance to recover if it’s just day after day” from extreme heat, says Harness.
In the US, the number of heat-related illnesses and deaths has been increasing since the 1980s. Heat is more deadly than more frightening weather events like hurricanes, floods and tornadoes combined. “It’s not even close to another extreme,” said Greg Carbin, chief of forecast operations at the NWS’s Weather Forecast Center.
NWS offices and other officials across Texas have warned residents to limit strenuous outdoor activities, take plenty of breaks (ideally indoors with air conditioning or at least shade) when working outdoors and to drink plenty of water on a regular basis. “When you’re thirsty,” says Quigley, “it’s already too late.”
Climate change is amplifying this and other heat events, as global average temperatures are already about two degrees F (one degree C) higher than in pre-industrial times. With the planet still warming as humans continue to burn fossil fuels that release heat-trapping greenhouse gases, heat waves will become more frequent, last longer and reach higher temperatures. Partly due to more extreme heat waves, an unusually hot summer in the past is now considered average. And today’s record hot summers will seem ho-hum in the future if we don’t significantly curb greenhouse gas emissions.
There is also some research suggesting that climate change increases the likelihood that weather patterns like these will persist. The idea is that the rapid warming of the Arctic is changing the jet stream — the fast-moving air current that guides weather systems around the Northern Hemisphere — in ways that keep these weather patterns in place.
In the coming days, the heat dome over Texas may shift slightly, warming the weather in some surrounding states. “There’s not much of a breakthrough in sight,” says Carbin.
Eventually, the pattern will loosen — though that doesn’t seem likely until sometime next week — and temperatures in Texas will fall back to the more seasonally above the 90s, which will be absurdly “a sense of relief,” says Quigley.