textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 612 AM CDT Wed Sep 2 2026

- A Heat Advisory is in effect for Cameron, Willacy, and Kenedy counties from noon to 6 PM Wednesday for heat indices up to 115 degrees.

- 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.

DISCUSSION

Issued at 1056 PM CDT Tue Sep 1 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. Temperatures in the lower layers of the atmosphere remain anomalously high (over the 90th percentile of climatology) through the week, supporting the stretch of above- average temperatures. Highs 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.

A Heat Advisory is in effect today from noon to 6 PM for inland and coastal Kenedy, Willacy, and Cameron counties as apparent temperatures are forecast to climb to 111-115 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 are possible through Friday.

Skies should be mostly dry through the week. 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 early next week. Despite the increase in rain chances, this is not anticipated to be a particularly wet pattern with 7-day cumulative QPF totals less than 0.25 inches. 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 Wed Sep 2 2026

VFR will prevail at the aerodromes through the next 24 hours.

MARINE

Issued at 1056 PM CDT Tue Sep 1 2026

Gentle to moderate south-southeasterly flow with slight seas prevail through the period. Breezy winds each 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 early next week.

CLIMATE

Issued at 1056 PM CDT Tue Sep 1 2026

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

Wednesday, September 2

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

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)

Subtropical ridging kept temperatures above normal across deep South Texas for much of August. Below are a few preliminary climate statistics for each climate site last month.

Brownsville had 16 days of high temperatures at or above 100 degrees. Six daily high temperature records were broken or tied.

Harlingen had 27 days of high temperatures at or above 100 degrees in August. Eleven high temperature records were broken or tied.

McAllen had 31 days of high temperatures at or above 100 degrees in August. McAllen is in a 39 day streak with high temperatures of at least 100 degrees (began July 24, 2026). This is the third longest 100+ degree day streak behind 2009 (49 days) and 2023 (43 days). Eight daily high temperature records were broken or tied in August.

PRELIMINARY POINT TEMPS/POPS

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

BRO WATCHES/WARNINGS/ADVISORIES

TX...Heat Advisory from noon today to 6 PM CDT this evening for TXZ251-254-255-351-354.

GM...None.