textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 613 PM CDT Tue Sep 15 2026

- A Special Weather Statement (SPS) is in effect through 6 PM this evening for Southern Hidalgo County as well as the inland and coastal portions of Kenedy, Willacy and Cameron counties, where heat indices are expected to reach 108-111 F, or briefly higher.

- Near record-breaking heat and major to extreme risks of heat related illnesses (levels 3/4 and 4/4) continue into Wednesday, improving to a mainly moderate risk (level 2/4) by Thursday though temperatures remain above average.

- Fire weather concerns continue this afternoon.

- Mostly dry conditions are expected through midweek, followed by a region-wide low to medium (20-40%) chances of rain Thursday into Friday and a low (10-15%) chance over the weekend before increasing just a bit early next week.

DISCUSSION

Issued at 115 PM CDT Tue Sep 15 2026

Triple-digit temperatures and heat index values will continue to be the primary weather concern across Deep South Texas through at least Thursday as the region remains under the influence of ridging aloft. Expect unseasonably hot temperatures to continue each afternoon, with the exception being along the lower Texas beaches. The combination of temperatures and humidity will result in heat index values ranging from 109-113 degrees each afternoon. A moderate (level 2 of 4) to major (level 3 of 4) heat risk will continue into early next week. If spending time outdoors, continue to practice heat safety to prevent heat related illnesses.

Guidance continues to highlight a pattern change by late Wednesday, as a plume of deep moisture content advects towards the region from the Gulf. In combination with diurnal instability and precipitable water values up to 2-2.4 inches, this would support some low to medium rain chances (around 20-50%) across the region. Overall rainfall amounts are forecast to remain fairly light at this time, but any slow-moving or efficient rain-producing showers or thunderstorms could bring locally higher amounts across portions of the region. Hot and rain-free conditions return over the weekend and into early next week.

AVIATION

(00Z TAFS) Issued at 613 PM CDT Tue Sep 15 2026

Gusty southeasterly winds (15-20 kt, gusting to 23-26 kt) continue through the next few hours before winding down later this evening and into the overnight hours, becoming light and/or variable to calm by late tonight. Winds shift out of the east tomorrow morning, increasing to near 10-15 kt, gusting to 20-25 kt in the afternoon. There is a low (15-20%) chance of isolated showers and a brief thunderstorm tomorrow afternoon, but probabilities are too low to include within the TAFs at this time.

MARINE

Issued at 115 PM CDT Tue Sep 15 2026

Generally favorable marine conditions will continue through mid to late week with low to moderate seas and light to moderate winds. Rain/storm chances increase late Wednesday through Friday, with chances coming to an end by the weekend. Locally enhanced winds and seas are likely within or near any showers or thunderstorms.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 80 97 80 95 / 0 20 50 60 HARLINGEN 76 100 76 98 / 0 20 40 50 MCALLEN 80 103 80 99 / 0 20 20 50 RIO GRANDE CITY 78 103 78 100 / 0 20 10 40 SOUTH PADRE ISLAND 82 89 81 88 / 0 20 50 60 BAYVIEW/PORT ISABEL 78 95 78 94 / 0 20 40 60

BRO WATCHES/WARNINGS/ADVISORIES

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