textproduct: Brownsville/Rio Grande Valley

DISCUSSION

Issued at 1240 PM CDT Sat Sep 13 2025

Satellite-derived PWATs this morning shows a boundary of dry air draped across South Texas and the southern Gulf waters, funneling isolated to scattered showers and thunderstorms north/northwestward over the southern Gulf. While this mornings convection and the couple showers that were able to push inland into Cameron county have limited surface heating, this should not be an obstacle for convection to initiate along the seabreeze this afternoon with clearing skies and abundant moisture (Satellite derived PWATs 1.7 to 2").

A subtropical ridge shifting westward will funnel in drier air aloft, reducing Sunday's PoPs to low (<30%). Early in the week, coastal troughing to our south sets up. This, paired with a trough across the central US translating east providing shortwave disturbances over south Texas midweek, will maintain a daily low to moderate chance (30-60%) of rain for much of the forecast. Expect a similar pattern seen this past week, with showers over the Gulf in the morning working their way inland through the afternoon. The greatest chances of rain will be each afternoon, primarily along the coast and RGV. Showers may be briefly heavy, leading to ponding in low-lying, poor drainage, and/or urban areas. Gusty winds and lightning are also possible in stronger storms.

The primary concerns into next week (outside of hazards brought by daily convection) are coastal hazards; persistent easterly flow across the Gulf has brought elevated seas. With high tide (1:25 AM Sunday) forecasts between 1.5-2 ft, this may lead to minor coastal flooding and warrant issuance of a Coastal Flood Statement overnight tonight. Increased wave heights will maintain a Moderate Risk of rip currents through the weekend.

AVIATION

(00Z TAFS) Issued at 519 PM CDT Sat Sep 13 2025

Moderate easterly winds are expected to become light to gentle or calm overnight before picking back up to moderate by tomorrow afternoon. VFR conditions continue with only a 20-30% of a quickly-passing afternoon shower and thunderstorm, mainly for KBRO, described in the PROB30.

MARINE

Issued at 1240 PM CDT Sat Sep 13 2025

Moderate easterly winds and slight seas will persist each afternoon through the period. An unsettled pattern bringing daily low to moderate (30-60 percent) chances of rain to the waters will continue through next week. Rain chances are lowest Sunday morning as dry air aloft is funneled over South Texas. By Monday, expect daily moderate rain chances through the week as a coastal low sets up near the Gulf waters.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 77 92 77 91 / 10 30 30 60 HARLINGEN 73 95 73 93 / 0 20 10 50 MCALLEN 76 97 75 95 / 10 20 10 40 RIO GRANDE CITY 74 97 73 95 / 10 30 10 30 SOUTH PADRE ISLAND 82 88 81 87 / 10 30 50 60 BAYVIEW/PORT ISABEL 77 90 77 90 / 0 20 30 50

BRO WATCHES/WARNINGS/ADVISORIES

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