textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 612 AM CDT Thu Sep 3 2026

- A Heat Advisory is in effect Thursday from 11 AM until 6 pm for Starr, southern Hidalgo, Cameron, Willacy, Kenedy Counties excluding the barrier islands.

- Major (level 3 of 4) to Extreme (level 4 of 4) Heat Risk is expected throughout much of Deep South Texas through early next week.

- A combination low relative humidity, dry grasses, and hot temperatures may raise concerns for favorable fire weather through Friday.

- Sea breeze showers and thunderstorms east of I-69C are possible each afternoon Labor Day Weekend and continuing into early next week.

DISCUSSION

Issued at 1036 PM CDT Wed Sep 2 2026

The hot conditions we've had over the past few weeks will continue through early September as ridging in the mid-upper levels remains dominant over deep South Texas for much of the forecast period.

A Heat Advisory is in effect today from 11 AM to 6 PM for inland and coastal Kenedy, Willacy, and Cameron counties as apparent temperatures are forecast to climb to 111-115 degF, with some locations briefly surpassing 116 degF. Widespread Major (level 3 of 4) to Extreme (level 4 of 4) risk of heat-related illness will continue across the CWA into this weekend. More Heat Advisories and/or Special Weather Statements are possible through Saturday. High temperatures will generally range from 100-107 daily (90s near the coast). Overnight lows offer little relief, near 80 in the RGV and mid-upper 70s in the Ranchlands.

Low relative humidity, breezy afternoon winds, and dry grasses/brush will warrant an eye kept on fire weather conditions. While ideal conditions don't align perfectly to warrant a Fire Danger Statement, caution should be exercised regarding outdoor burning activities, as grasses are favorable to ignite. Relative humidity will begin to increase this weekend, lowering the threat of fire weather conditions, but drought conditions are not anticipated to improve.

Rain chances increase into Labor Day weekend as coastal troughing near the surface will support isolated showers and thunderstorms moving inland along the sea breeze. Activity should remain primarily east of US281, with PoPs increasing to 15-25% Saturday and persisting each afternoon through the middle of next week. Despite the increase in rain chances, this is not anticipated to be a particularly wet pattern with daily QPF totals less than a tenth of an inch. Be sure to have access to a shelter for any outdoor activities in the case of a shower... and for some AC!

AVIATION

(12Z TAFS) Issued at 612 AM CDT Thu Sep 3 2026

VFR continues to be anticipated at the aerodromes through the next 24 hours. Limited cloud cover will occur, with breezy daytime winds and a lighter onshore flow at night.

MARINE

Issued at 1036 PM CDT Wed Sep 2 2026

Gentle to moderate south-southeasterly flow with slight seas prevail through the period. Breezy winds this afternoon will leave choppy conditions on the Laguna Madre and nearshore waters. An isolated shower or thunderstorm is possible each day over the Gulf, with chances increasing to 15-30% Saturday into the middle of next week.

CLIMATE

Issued at 1036 PM CDT Wed Sep 2 2026

Record high temperatures may be tied or broken across the Rio Grande Valley today. The existing record high temperatures for Brownsville, Harlingen, and McAllen are listed below.

Thursday, September 3

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

Friday, September 4

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

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 99 81 98 81 / 0 0 0 0 HARLINGEN 103 78 102 77 / 0 0 0 0 MCALLEN 105 82 104 81 / 0 0 0 0 RIO GRANDE CITY 106 80 105 79 / 0 0 0 0 SOUTH PADRE ISLAND 90 82 90 82 / 0 0 0 0 BAYVIEW/PORT ISABEL 97 79 96 79 / 0 0 0 0

BRO WATCHES/WARNINGS/ADVISORIES

TX...Heat Advisory from 11 AM this morning to 6 PM CDT this evening for TXZ251>255-351-354-355.

GM...None.