textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 1042 PM CDT Thu Jul 9 2026

- Low to medium (30-60%) rain chances today from possible rounds of showers and thunderstorms.

- High moisture content could result in heavy rain. A few areas may receive up to an inch or more, most likely along/east of US-281/I-69 E.

- Afternoon heat indices around 100-105 F escalate to 105-110 F this weekend, bringing a moderate risk (level 2 of 4) of heat related illness.

- There is a moderate risk of rip currents Friday.

DISCUSSION

Issued at 1042 PM CDT Thu Jul 9 2026

An inverted trough will continue to funnel deep tropical moisture over deep South Texas Friday, resulting in the highest rain chances of the forecast period. PWAT values are expected to peak between 2.0 to 2.3 inches, highest along the coast, supporting isolated to scattered showers and thunderstorms into this weekend. Should activity develop over the Gulf and NE Mexico overnight, activity would then spread inland with the highest PoPs across the RGV and coast Friday morning before expanding further inland through the afternoon. PoPs generally range from 30 to 60% Friday before decreasing to 20 to 50% Saturday as upper level support shifts out.

Despite progressive storm motion, the anomalously moist airmass will support efficient rainfall rates. As a result, localized rainfall totals of 2 to 3 inches remain possible where multiple rounds of showers and thunderstorms train over the same areas. Given relatively dry antecedent conditions and high flash flood guidance (1-hour FFG 2-3+ inches), any flooding concerns should remain localized.

Confidence in evolution of Friday's convection remains somewhat limited. Latest hi-res guidance ranges from widely scattered convection to little more than isolated activity confined near the coast. Confidence is higher in the occurrence of showers than their overall coverage; opted to maintain elevated PoPs across the CWA.

Rain chances continue to decrease Sunday into early next week as ridging builds over Central CONUS, suppressing widespread convection and shifting the deepest moisture away from the region. Persistent Gulf moisture will still support isolated afternoon showers and thunderstorms along the sea breeze east of US-281, with PoPs generally in the 10-30% range through Tuesday. Forecast confidence decreases come the middle of next week as long range guidance continues to differ on the evolution and location of a front along the northern Gulf coast.

Temperatures will remain seasonable through the forecast, if not a degree or two below normal, with afternoon highs in the 90s (upper 80s along the coast). Persistent Gulf humidity will allow peak heat index values in the triple digits, as high as 110 this weekend, and will support a moderate risk of heat-related illness. Relief from temperatures will be felt with increased cloud cover and rain. At local beaches, there is a moderate risk of rip currents.

AVIATION

(00Z TAFS) Issued at 627 PM CDT Thu Jul 9 2026

VFR should prevail, but may be intermittently plagued with isolated to scattered showers and thunderstorms through the TAF cycle. Gusty southeasterly winds diminish overnight, increasing again late Friday morning with gusts to 25 kts. Abundant moisture may lower ceilings to MVFR levels ahead of sunrise Friday.

Showers currently over the area are diminishing. An isolated shower or two cannot be ruled out between now and 06Z, but maintained VFR prevailing for the near term. Rain chances are non- zero past 06Z and increase late morning through the end of the cycle. Due to uncertainty in coverage, maintained PROB30s during the day Friday. Any showers or storms that pass over an airfield can bring heavy rain reducing visibility, low ceilings, gusty winds, and lightning.

MARINE

Issued at 1042 PM CDT Thu Jul 9 2026

Moderate southeasterly flow with slight seas persists. Isolated to scattered showers and thunderstorms are possible each day into the weekend, bringing briefly gusty winds, heavy rain, and elevated seas. Moderate rain chances (40-60%) Friday gradually decrease each day into the next week. This weekend, seas build to moderate into next week with increasing swells.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 92 78 92 81 / 40 40 50 10 HARLINGEN 93 75 93 78 / 30 30 60 10 MCALLEN 96 78 96 81 / 40 10 50 10 RIO GRANDE CITY 96 76 96 79 / 30 10 50 10 SOUTH PADRE ISLAND 87 80 87 82 / 40 50 50 20 BAYVIEW/PORT ISABEL 90 77 90 80 / 40 40 50 20

BRO WATCHES/WARNINGS/ADVISORIES

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