textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 621 AM CDT Fri Jul 10 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

(12Z TAFS) Issued at 621 AM CDT Fri Jul 10 2026

Through 12z Saturday....Latest radar and satellite data depicted showers and thunderstorms advancing northward from over Tamaulipas, Mexico towards the Mid to Lower Rio Grande Valley this morning. Low VFR to high MVFR ceilings have already moved into the area in response to the activity moving in.

Over the next hour or two, expect for flying conditions to deteriorate as clouds continue to increase in coverage and lower in elevation, and showers and thunderstorms increase. Have TEMPO groups between 12z-15z for BRO and HRL to account for the likelihood of showers and thunderstorms during that time, and VCSH/VCTS for all of the TAF sites (BRO, HRL, and MFE) through the morning hours. Have Prob30 groups for showers and thunderstorm potential later this afternoon into this evening as well. Any showers or thunderstorms that move over a TAF site will have the capabilities of briefly reducing cigs/vsbys to MVFR-LIFR levels. Flying conditions are expected to improve later this evening into tonight as showers and storms come to an end and cloud conditions improve.

Winds will continue out of the southeast with speeds between 5-15 kts through the TAF period, outside of any thunderstorms. Winds could gusts as high as 20-25 kts, specifically during the afternoon hours.

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 81 94 80 / 50 10 20 0 HARLINGEN 93 77 94 77 / 50 0 20 0 MCALLEN 95 80 98 79 / 40 10 30 10 RIO GRANDE CITY 96 78 98 78 / 30 10 40 10 SOUTH PADRE ISLAND 87 82 88 81 / 50 10 10 10 BAYVIEW/PORT ISABEL 91 79 92 79 / 50 10 10 0

BRO WATCHES/WARNINGS/ADVISORIES

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