textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 636 AM CDT Mon Sep 21 2026

- Sustained daily opportunity for rainfall, especially Wednesday and Thursday.

- Continued hot temperatures, but no extremes.

- Elevated risk of rip currents at the local beaches.

DISCUSSION

Issued at 1009 PM CDT Sun Sep 20 2026

Broad 500 mb high pressure will remain the dominant weather feature over Deep South Texas and the Rio Grande Valley through the forecast period. However, the center of the high, positioned generally over east Texas, will produce a more easterly and moist flow off of the neighboring Gulf of America, with precipitable water values hovering near 2 inches. This will have the result of enhancing the daily seabreeze boundary, with isolated to scattered showers and thunderstorms across the BRO CWFA. At this time, the best chances for precipitation are Wednesday and Thursday, with the best combination of moisture and easterly flow.

Temperature-wise, above normal to well above normal values will occur, despite the autumnal equinox officially kicking-off on Tuesday 22 September at 7:04 PM CDT.

Finally, winds and seas along the Lower Texas Coast will produce a low to moderate risk of rip currents at the local beaches through the period.

AVIATION

(12Z TAFS) Issued at 636 AM CDT Mon Sep 21 2026

Isolated to scattered showers and thunderstorms are possible this afternoon along the sea breeze, with impacts most likely at MFE. HiRes models continue to show convection developing along the sea breeze this afternoon, moving into the vicinity of MFE by mid afternoon. The probability for convection at BRO and HRL remain too low for inclusion in the TAFs.

Any showers or thunderstorms that do move over an airfield will likely be brief, but may produce MVFR to IFR conditions. Otherwise, VFR conditions are forecast with light and variable winds this morning increasing out of the east this afternoon.

MARINE

Issued at 1009 PM CDT Sun Sep 20 2026

High pressure over the western Gulf of America will produce light to moderate winds and low to moderate seas along the Lower Texas Coast through the next several days. Small Craft Should Exercise Caution and Small Craft Advisory are not likely to be needed.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 96 80 95 80 / 20 10 40 10 HARLINGEN 99 76 98 76 / 20 10 40 10 MCALLEN 102 79 100 79 / 30 0 50 10 RIO GRANDE CITY 102 78 99 77 / 10 0 40 0 SOUTH PADRE ISLAND 89 82 89 83 / 10 10 30 20 BAYVIEW/PORT ISABEL 95 79 94 79 / 20 20 30 10

BRO WATCHES/WARNINGS/ADVISORIES

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