Parts of Texas are experiencing heat courtesy of the same ridge that impacted parts of the Southwest and Mexico.
The first full week of meteorological summer saw temperatures soar into the 100s in Texas’ Lower Rio Grande Valley, with expectations that the dangerous heat will continue through the workweek.
The extreme temperatures in parts of South and Central Texas are courtesy of a heat dome – the same ridge of high pressure that impacted parts of the Southwest and Mexico with record temperatures. However, humidity values are much higher in the Lone Star State, sending the heat index into life-threatening territory.
On Tuesday, National Weather Service offices in South Texas warned that the heat index 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 heat indices 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.
A sprawling area of high pressure is resulting in a heat wave that stretches from California to Texas.
(FOX Weather)
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The FOX Forecast Center warned that Wednesday and Thursday will likely be the peak of the heat wave in the Lone Star State as air temperatures reach near 100 degrees in Brownsville and low 100s in San Antonio.
Despite the extreme heat, the Electric Reliability Council of Texas (ERCOT) has not indicated that the demand for electricity is expected to outpace supply.
On Tuesday, the state’s power grid was operating 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 heat index chart shows how temperature and humidity relate.
(NOAA/NWS / FOX Weather)
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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) during the week 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 advisories, as their warmest days will only be about 5 degrees above average.
Both metros are expected to reach the middle 90s by Wednesday and Thursday; however, the heat index could make it feel closer to 100 degrees.
(FOX Weather)