textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 1211 PM CDT Mon Aug 31 2026

- Hot temperatures, near record to record-breaking, are expected to continue into Labor Day Weekend. - Widespread Major (Level 3 of 4) to Extreme (Level 4 of 4) Heat Risk of heat-related illness is expected each day. - Isolated sea breeze showers and thunderstorms are possible each afternoon, especially during Labor Day Weekend. - The National Hurricane Center is monitoring a disturbance across the northern Gulf, moving west-northwest toward the northwest Gulf, with a high (70 percent) chance of development in 48 hours. No direct impacts are expected across Deep South Texas, with a potential increase in rip currents along the coast.

DISCUSSION

Issued at 1211 PM CDT Mon Aug 31 2026

The 500mb ridge of high pressure continues to push towards the Southeast US, which will maintain mid-summer like heat and a persistent influx of tropical moisture into Texas into next weekend. Weaker pressure along the Gulf coast around the southern edge of the ridge may combine with the added moisture to initiate isolated sea breeze showers or thunderstorms during the afternoon hours, mainly through Labor Day Weekend into early next week. Current POPs sit low around 15 percent or less into Saturday, with a low to medium (20 to 30 percent) chance Sunday and Labor Day. Model QPF is still bleak and isolated, with no drought relief expected, but has bumped up towards a quarter of an inch for the week.

The National Hurricane Center is issuing advisories on Potential Tropical Cyclone Five, with a high (70 percent) chance to become a short-lived Tropical Depression or Tropical Storm before making landfall near the TX/LA border late tomorrow. Any development could potentially create more subsidence locally, leaning into warmer and more stable air across South Texas into Wednesday, as well as increase the potential for life-threatening rip currents along the coast. Otherwise, this system will not impact Deep South Texas.

The added humidity on top of above normal to near record high temperatures will continue a widespread Major (level 3 of 4) to Extreme (level 4 of 4) Heat Risk for heat-related illness each day, with little to no relief each night. Heat Advisories may be needed, especially Wednesday through Saturday.

AVIATION

(18Z TAFS) Issued at 1211 PM CDT Mon Aug 31 2026

VFR conditions are expected to prevail through the TAF period with breezy southeasterly winds this afternoon and again Tuesday afternoon. There is a very low chance of an isolated sea breeze shower or thunderstorm over the next couple of hours.

MARINE

Issued at 1211 PM CDT Mon Aug 31 2026

Light to moderate southeasterly winds and low to moderate seas are expected to prevail across the coastal waters of Deep South Texas through the forecast period. A daily moderate chop is expected on the bay next week with Gulf seas of generally 1 to 3 feet. There is a low (less than 25 percent) chance of showers and thunderstorms. The National Hurricane Center is issuing advisories on Potential Tropical Cyclone Five, with a high (70 percent) chance to become a short-lived Tropical Depression or Tropical Storm before making landfall near the TX/LA border late tomorrow.

CLIMATE

Issued at 1036 PM CDT Sun Aug 30 2026

A broad and anomalously strong 591-594 dam sub-tropical heat ridge over the Southern Plains to the Ohio Valley will continue to bring hotter than normal temperatures to Deep South Texas and the Rio Grande Valley this week. Mostly sunny skies and a positive feedback loop between the heat and very dry conditions will help to aid in record to near record-breaking temperatures at times this week. Below is a list of the record highs from August 31st to September 4 from our three official climate sites.

Record High Temperatures from August 31st to September 4th:

Monday, August 31, 2026

Brownsville: 103F (2023) Harlingen: 104F (1958) McAllen: 104F (2023, 2017)

Tuesday, September 1, 2026

Brownsville: 100F (2023, 2020) Harlingen: 103F (1928, 1952) McAllen: 106F (2018)

Wednesday, September 2, 2026

Brownsville: 99F (2018) Harlingen: 104F (1928, 1937) McAllen: 106F (2018)

Thursday, September 3, 2026

Brownsville: 102F (2011) Harlingen: 106F (2011) McAllen: 106F (2011)

Friday, September 4, 2026

Brownsville: 103F (2011, 2000) Harlingen: 107F (2011) McAllen: 108F (2011)

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 80 98 80 99 / 0 0 0 0 HARLINGEN 76 102 76 102 / 0 0 0 0 MCALLEN 80 104 81 104 / 0 0 0 0 RIO GRANDE CITY 78 105 79 105 / 0 0 0 0 SOUTH PADRE ISLAND 81 90 81 90 / 0 0 0 0 BAYVIEW/PORT ISABEL 78 96 79 97 / 0 0 0 0

BRO WATCHES/WARNINGS/ADVISORIES

TX...None. GM...None.