Heat dome baking Southwest bleeds into Texas with stretch of dangerous triple-digit temperatures

The FOX Forecast Center warned that Thursday will likely be the peak of the heat wave in Texas as air temperatures approach 100 degrees in Brownsville and San Antonio.

The first full week of meteorological summer saw temperatures soar into the 100s in Texas' Lower Rio Grande Valley, and the dangerous heat is expected to continue through Thursday.

The extreme temperatures in parts of South and Central Texas are courtesy of a heat dome – the same ridge of high pressure impacting parts of the Southwest and Mexico with record temperatures. However, humidity values are much higher in the Lone Star State, sending feels-like temperatures into life-threatening territory.

The FOX Forecast Center warned that Thursday will likely be the peak of the heat wave in Texas as air temperatures approach 100 degrees in Brownsville and San Antonio.

This graphic shows the forecast high temperatures in Texas on Thursday, June 6, 2024.
(FOX Weather)


Nearly two dozen records were set across the country on Wednesday, including larger cities in Texas like Harlingen, Brownsville and Del Rio. More than a dozen records could be broken in the West on Thursday.

On Tuesday, National Weather Service offices in South Texas warned that the feels-like temperatures approached 120 degrees in communities when the actual air temperature was in the lower 100s.

High dew points – the measure of the amount of water vapor in the air – caused the feels-like temperatures to skyrocket, and values are not expected to relax anytime soon.

In communities with a high dew point, sweat doesn’t evaporate as easily because the air is already nearly saturated. This prevents the natural cooling systems of people and animals from optimally performing.


This graphic shows the warmest daily heat index for the next 5 days in Brownville, Texas.
(FOX Weather)


Other cities will see temperatures above 100 degrees, including Sonora, Sanderson and Uvalde. And in Zapata, Texas, temperatures could approach 110 degrees.

Kingsville, Texas, hit 102 degrees on Wednesday with a dew point of 80 degrees, which led to an incredible heat index of 125 degrees. Not far behind, McAllen hit 100 degrees with a dew point of 81 degrees, leading to a heat index of 124 degrees.

Feels-like temperatures on Thursday will be just as extreme, with many parts of Texas expected to reach heat index values higher than 100 degrees and approaching 120 degrees.

Despite the extreme heat, the Electric Reliability Council of Texas (ERCOT) has not indicated that the demand for electricity is expected to outpace supply.

So far this week, the state’s power grid has operated under normal conditions for some 27 million customers.

Last summer, ERCOT set 10 new all-time records, with Aug. 10 leading the way with a peak demand of 85,464 megawatts. The high usage caused the utility provider to urge customers to conserve electricity or face rolling blackouts.

This graphic shows heat risk in Texas.
(FOX Weather)



With the latest round of heat, some communities even fall under the highest risk category on the NOAA's HeatRisk scale.

San Antonio and McAllen are expected to reach a Level 4 (magenta) when temperatures peak. A Level 4 signifies heat that is either rare or long in duration. Health systems can be impacted by an influx of patients with heat-related illnesses

Metros such as Houston and Dallas are not included in the heat alerts, as their warmest days will only be about 5 degrees above average.

Both metros are expected to reach the mid-90s on Thursday; however, the feels-like temperatures could make it feel closer to 100 degrees.

This graphic shows heat alerts in Texas.
(FOX Weather)