textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 630 AM CDT Tue Sep 8 2026

- A Heat Advisory is in effect from Noon to 6 OM CDT for Inland Kenedy, Inland, Willacy, Inland Cameron, Hidalgo, and Starr Counties.

- Widespread Major (level 3 of 4) to increasing areas of Extreme (level 4 of 4) Heat Risk will continue through early next week.

- There remains a low (20-30%) chance of sea breeze showers and thunderstorms each afternoon through Thursday.

DISCUSSION

Issued at 1046 PM CDT Mon Sep 7 2026

Hot, mainly dry, and at times breezy conditions will continue to be the theme through early next week as an anomalously strong and elongated 591-594 dam heat ridge complex remains anchored over the southern U.S. This persistent and dominant feature in our pattern will continue to foster record to near record-breaking heat over the next several days (see CLIMATE SECTION for more details). High temperatures are progged to continue in the upper 90s to mid 100s through the forecast period with overnight lows in the 70s to lower 80s. Peak heat indices ranging between 105-115F degrees will warrant day-to-day or near daily Special Weather Statements (SPSs) and/or Heat Advisories through this week. The combination of very hot temperatures during the day and very warm temperatures at night providing little relief, widespread Major (Level 3 of 4) Heat Risk to increasing areas of Extreme (Level 4 of 4) Heat Risk will be the case through this week (at least).

Aided by persistent southeasterly winds, low grade (20-30%) chances for showers and thunderstorms along the sea breeze is possible Tuesday through Thursday of this week as Deep South Texas sits on the on the southern periphery of the aforementioned heat ridge. The best chances for any showers and storms will be along and east of IH- 69C/US-281. Additional rain chances (20-30%) are possible Sunday through the early part of next week, according to a few computer models.

AVIATION

(12Z TAFS) Issued at 630 AM CDT Tue Sep 8 2026

Predominantly VFR conditions are forecast to continue through the period, however isolated showers and thunderstorms are possible this afternoon. Probabilities for thunderstorms are highest at MFE, around 30%, with convective models consistently depicting thunderstorm development over the past several runs. MVFR to IFR conditions may briefly develop if any convection moves over an airfield.

Winds are forecast to remain southeasterly today, with wind speeds and gusts increasing this afternoon. Light and variable winds are forecast across the area tonight.

MARINE

Issued at 1046 PM CDT Mon Sep 7 2026

Outside of any shower and thunderstorms, marine conditions will remain favorable through this week with low to moderate winds and seas (i.e. wave heights between 1-3 feet). Moderate seas are possible over the weekend into early next week.

CLIMATE

Issued at 1046 PM CDT Mon Sep 7 2026

Record to near record-breaking temperatures are possible through Saturday, courtesy of a persistent and strong 591-594 dam heat ridge complex established over the southern U.S. Below is a list of the record highs from Tuesday September 8th to Saturday September 12th.

Tuesday September 8, 2026:

Brownsville: 102F set in 2023 Harlingen: 103F set in 2023 McAllen: 105F in 2012

Wednesday September 9, 2026:

Brownsville: 102F in 1893 Harlingen: 102F in 2023 McAllen: 103F in 2023 & 2016

Thursday September 10, 2026:

Brownsville: 102F in 2023 Harlingen: 102F in 2023 McAllen: 105F in 2023

Friday September 11, 2026:

Brownsville: 100F in 1900 & 1893 Harlingen: 103F in 1937 McAllen: 103F in 2023

Saturday September 12, 2026:

Brownsville: 100F in 1919 Harlingen: 101F in 2011 & 1930 McAllen: 103F in 1987

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 98 80 96 80 / 20 10 30 0 HARLINGEN 101 76 100 76 / 20 0 30 0 MCALLEN 104 81 102 80 / 20 0 30 0 RIO GRANDE CITY 104 79 103 79 / 10 10 10 0 SOUTH PADRE ISLAND 90 82 89 81 / 10 10 20 0 BAYVIEW/PORT ISABEL 96 79 95 78 / 10 10 20 0

BRO WATCHES/WARNINGS/ADVISORIES

TX...Heat Advisory from noon today to 6 PM CDT this evening for TXZ251>255-353.

GM...None.