Excessive Heat in Southern Hidalgo County, Texas

McAllen International Airport (KMFE) recorded heat indices between 117 and at least 122F for 7 hours, from 12:53-7:53 PM CDT on May 9, 2024. Peak value of 122F (hourly) was reached at 453 CDT. Between the hours of 11:53 AM to 8:35 PM CDT (9 hours), heat indices were at least 111F. Weslaco Mid Valley Airport (AWOS) recorded heat indices between 116-122F for 3 hours, from 3:55-6:55 PM CDT on May 9, 2024. Between the hours of 12:55 PM to 7:35 PM CDT (6.5 hours), heat indices were at least 111F. Peak value of 122 occurred at 635 PM CDT. Other observing locations (Mesonet, Remote Automated Weather Station) recorded similar values.

As of this writing, there were no known direct fatalities from the heat, but there was an unknown increase in hospitalizations compared with other times in early May.

An unseasonably strong sub-tropical ridge/heat dome centered over central and southern Mexico strengthened and shifted northward towards the Rio Grande Valley/Deep South Texas region. Temperatures at around 5,000 feet above the ground soared to 78 to 86 degrees Fahrenheit over the local area. This translated to surface temperatures rising into the upper 90s to mid 100s from May 7-9. Combined with dewpoint temperatures in the 70s to around 80, this produced apparent, or feels-like temperatures, between 111-116F across locations along and east of IH-69C/US 281 from Brooks/Hidalgo County into Cameron, Willacy, and Kenedy County. The hottest temperatures were located from the mid-lower Rio Grande Valley northward along I-69E and I-69C, peaking on May 9th.