Excessive Heat in Willacy, Texas

Harlingen Valley International Airport (KHRL) recorded max heat indices between 113-120F for 4 hours, from 12:52-4:52 PM CDT on May 27, 2024. Excessive heat criteria with values between 116-120F for a couple of hours, from 1:30-3:30 PM CDT. By proxy, and using a reference of the Texas AgriScience Center along the Willacy/Hidalgo line, which had 1.5 hours of heat index between 116 and 119, inland Willacy is assumed to have three hours of excessive heat index values.

A slightly stronger sub-tropical ridge/heat dome centered over central and southern Mexico returned northward towards the Rio Grande Valley and Deep South Texas. At five thousand feet above ground, the temperature soared anywhere from 78 to 90 degrees Fahrenheit, which translated into another short-lived but intense heat wave over the region with surface temperatures rising into the upper 90s to mid 100s from May 26-30. The combination of heat and dewpoint temperatures well into the 70s to around 80, heat indices ranged between a sweltering 111F-126F across parts of Deep South Texas and the Rio Grande Valley. The hottest temperatures were once again located from the mid-lower Rio Grande Valley northward along I-69E and I-69C; several hours with values of 116 or higher - considered Excessive Heat - were noted each day in many parts of the region.