Excessive Heat in Southern Hidalgo County, Texas

McAllen International Airport (KMFE) recorded max heat indices between 111-117F for 6 hours from 11:53 AM-5:53 PM CDT on May 21, 2024. A period of excessive heat - 116F or higher - lasted from 230 PM to 430 PM CDT.

A strong upper-level subtropical ridge/heat dome centered over central and southern Mexico strengthened and shifted northward towards the Rio Grande Valley and Deep South Texas ranchlands the week prior to Memorial Day. The strong ridge aided lower level temperatures at around five thousand feet to soar to between 78 and 86F, which translated to surface temperatures rising into the upper 90s to mid 100s on most days between May 21-25. With dewpoint temperatures well into the 70s to around 80, apparent temperatures (feels like temperatures) ranged anywhere between 111-116F across parts of Deep South Texas and the Rio Grande Valley with a few locales reaching higher than this. The hottest apparent temperatures were located along and east of IH-69C from Hidalgo and Brooks County to Cameron, Willacy, and Kenedy County - but all of Deep South Texas observed at least dangerous heat levels by local definition (111F or higher for at least two hours) on most days.

Actual temperatures during the period were even hotter than the peak of the summer heat (late July through mid August) for most areas. The month would shatter all-time temperature records by 1 to more than 3 degrees.