textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 623 AM CDT Wed Sep 23 2026

- Low to medium (20-60%) rain chances nearly each day to continue through mid next week across Deep South Texas, mainly along the sea breeze.

- Above average temperatures (around 5-10 degrees above normal) to continue through the end of September.

- Moderate (level 2 out of 4) to major (level 3 out of 4) heat risk continue across the region. Continue to practice heat safety to prevent heat-related illnesses.

DISCUSSION

Issued at 1047 PM CDT Tue Sep 22 2026

The heat will continue to be the primary concern through early next week. However, there are indications of a potential weather pattern change that will feature things cooling down (slightly) mid to late next week, or as we close the month of September out and open the books to October. It's worth noting that climatologically October is one of our fastest cooling months (where our average temperatures falls quickly from the beginning of the month to the end of the month). Additionally, there will be near day-to-day chances for showers and thunderstorms along the sea breeze through the middle parts of next week, as the weather pattern attempts to become a bit more unsettled (something we'll be monitoring closely as we move into October).

Through the remainder of this week into early next week, forecast models/ensembles continue to advertise the persistent and broad 591- 594 mb heat dome strengthening over the region. This will result in a continuation of hotter than normal temperatures throughout Deep South Texas. High temperatures through the forecast period will range between the mid 90s to lower 100s with the hottest temperatures occurring in the Sunday through Tuesday of next week timeframe. Widespread Moderate (Level 2 of 4) to Major (Level 3 of 4) with pockets of Extreme (Level 4 of 4) Heat Risk will be common through the forecast period. Peak heat indices will mainly range between 100-110F degrees through the forecast period.

On a persistent easterly flow pattern, low to medium (20-60%) chances for some much needed rainfall in the form of isolated to scattered showers and thunderstorms along the sea breeze is possible across Deep South Texas and the Rio Grande Valley nearly each day through mid next week. The best chances and coverage looks to be Wednesday through Friday. Chances decrease slightly over the weekend before picking back up again mid next week as the aforementioned heat ridge potentially breaks down. Currently, we're outlooked under a non-severe or general risk for thunderstorms over the next couple of days by the Storm Prediction Center (SPC). We're not outlooked under any Excessive Rainfall Outlook by the Weather Prediction Center.

AVIATION

(12Z TAFS) Issued at 623 AM CDT Wed Sep 23 2026

VFR will prevail at the aerodromes through the next 24 hours, with light to moderate winds and clear to partly cloudy skies. A TEMPO for convection remains added to the TAFs, with timing based on the HRRR model.

MARINE

Issued at 1047 PM CDT Tue Sep 22 2026

Generally, favorable marine conditions will persist through the middle parts of next week with low to moderate seas (wave heights between 1-3 feet) and winds.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 96 80 96 80 / 50 20 60 40 HARLINGEN 98 78 98 76 / 50 20 40 20 MCALLEN 100 79 99 79 / 50 0 70 30 RIO GRANDE CITY 99 77 98 76 / 30 0 60 40 SOUTH PADRE ISLAND 90 83 89 83 / 40 30 40 50 BAYVIEW/PORT ISABEL 94 79 94 79 / 40 30 40 40

BRO WATCHES/WARNINGS/ADVISORIES

None.