textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 1140 AM CDT Sun Aug 16 2026

- Hot, mainly dry, and at times breezy conditions will continue through next week.

- There is a 20-30% chance for an isolated to scattered shower or thunderstorm along the sea breeze today and again on Monday especially along and east of IH-69C/US-281; best timing between 11am-5pm CDT.

- Though no headlines are out at this time, fire weather concerns will remain on the table through next week.

- Generally favorable marine conditions are expected through next week with low to moderate winds and seas; Small Craft Exercise Caution (SCEC) conditions are possible over the Laguna Madre mid to late week.

DISCUSSION

Issued at 1140 AM CDT Sun Aug 16 2026

Hot, mainly rain-free, and at times breezy conditions will prevail through the forecast period or through next week across Deep South Texas and the Rio Grande Valley as a strong and broad 594-597 dam sub-tropical heat dome remains anchored overhead.

High temperatures during this time will range from the upper 90s to the mid 100s. Combine that with dewpoint temperatures in the 70s and heat indices will generally range between 105-115F degrees each day through next week. This will continue to result in Moderate (Level 2 of 4) to Major (Level 3 of 4) Heat Risk with pockets of Extreme (Level 4 of 4) Heat Risk through next week. Additional Special Weather Statements (SPSs) will be needed in the coming days across at least parts of the region with areas closer to the coast most favored due to higher humidity levels.

Latest visible satellite imagery and radar data depicted isolated showers near Bayview associated with the sea breeze in addition to a cumulus field from the uncreased sfc heating. Have decided to bump up PoPs slightly this morning/afternoon for areas near the coast to account for the potential for an isolated shower or thunderstorm this afternoon. While today presents a lower, yet non-zero probability for showers and thunderstorms, forecast models continue to suggest that Monday will be the better day for showers and thunderstorms along the sea breeze. Currently, we have low (20%) probabilities for today inland and low-medium (20-40%) chances over the Gulf Waters today, and (20-30%) chances on Monday with the greatest confidence being aligned along and east of the IH-69C/US- 281 corridor. The best timing for any showers or thunderstorms will be between the hours of 11am-5pm CDT.

The persistently hot and dry antecedent pattern with high evaporation rates and at times breezy conditions will aid in increased fire weather concerns through next week, particularly in the Tuesday through Friday time period as minimum relative humidity values get to near Fire Danger Statement (RFD) criteria. Even though, we do not have any fire weather headlines at this time, we urge that you continue to exercise fire weather safety measures.

AVIATION

(18Z TAFS) Issued at 1140 AM CDT Sun Aug 16 2026

Through 18z Monday....VFR conditions will prevail through the 18z TAF cycle.

Southeast winds 5-15 kts with isolated gusts as high as 20 kts will continue through this afternoon/evening before waning later this evening/tonight. Tonight, winds will trend towards light and variable to calm if not a slight component out of the southeast with wind speeds up to 5 kts. Winds will pick up in magnitude once again on Monday as mixing heights increase.

MARINE

Issued at 1140 AM CDT Sun Aug 16 2026

Generally favorable marine conditions are expected along the Lower Texas Coast through the next several days, with light to moderate winds and low to moderate seas in place. However, winds may increase over the Laguna Madre mid to late week, which could require Small Craft Should Exercise Caution at times.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 79 96 79 97 / 0 20 0 10 HARLINGEN 76 98 76 100 / 0 20 0 10 MCALLEN 80 101 79 102 / 0 20 0 0 RIO GRANDE CITY 78 102 77 103 / 0 10 10 0 SOUTH PADRE ISLAND 80 89 80 89 / 0 10 0 0 BAYVIEW/PORT ISABEL 78 94 78 96 / 0 10 0 10

BRO WATCHES/WARNINGS/ADVISORIES

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