487 FXUS64 KBRO 271114 AAB AFDBROArea Forecast Discussion...UPDATED National Weather Service Brownsville TX 614 AM CDT Sat Sep 27 2025
...New AVIATION...
.DISCUSSION... Issued at 1019 PM CDT Fri Sep 26 2025
Ridging aloft from a building high pressure over northeastern Mexico is expected to keep dry conditions (less than 10% PoP`s) across most of Deep South Texas and the Rio Grande Valley today through the daytime tomorrow, outside of a low (15-20%) chance of rain for southern portions of Cameron County tomorrow afternoon. Late tomorrow night through Monday night, a low (15-30%) chance of showers develops and continues across coastal areas in response to weak mid-level disturbances passing over southern-central Texas, expanding inland along the seabreeze boundary throughout Monday afternoon, remaining mostly east of US-281/I-69 C, with the highest PoP`s closer to the coast. Following, ridging aloft enhances again as a mid-level high expands over northwestern Mexico, causing probabilities of rain to decrease from a low (15-20%) chance on Tuesday afternoon across portions of the lower Rio Grande Valley to a less than 15% chance for Wednesday and Thursday. PoP`s look to increase again later in the work week and into next weekend as a trough over the eastern CONUS extends southwestward into the Southern Plains, leading to 20-30% PoP`s along the afternoon seabreeze on Friday and Saturday.
High temperatures are likely to remain near average, warming to slightly above normal throughout the later part of this upcoming week as ridging aloft decreases cloud coverage with inland highs increasing from low/mid 90`s over the weekend to mid/upper 90`s by Wednesday. Highs in the mid 80`s persist along the immediate coast. Mostly minor (level 1 of 4) heat risks continue each day, though pockets of moderate (level 2 of 4) heat risks are possible across the upper Rio Grande Valley and the Rio Grande Plains on Wednesday and Thursday. Average overnight lows are expected to continue, falling to the upper 60`s/low 70`s inland and upper 70`s along the immediate coast.
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.AVIATION... (12Z TAFS) Issued at 612 AM CDT Sat Sep 27 2025
VFR conditions are expected to prevail through the TAF period with occasional ENE gusts this afternoon around 15 kts.
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.MARINE... Issued at 1019 PM CDT Fri Sep 26 2025
Favorable marine conditions continue as gentle to moderate northeasterly to easterly winds result in slight (1-2 feet) seas. A low to medium (15-30%) chance of showers and thunderstorms returns tomorrow, increasing to a low to medium (20-40%) late tomorrow night through Monday night with additional chances possible throughout the remainder of the forecast period.
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.PRELIMINARY POINT TEMPS/POPS... BROWNSVILLE 91 73 89 74 / 10 10 20 20 HARLINGEN 93 68 91 69 / 0 0 10 10 MCALLEN 97 72 94 72 / 0 0 10 10 RIO GRANDE CITY 97 68 94 69 / 0 0 0 0 SOUTH PADRE ISLAND 87 78 86 79 / 10 10 20 20 BAYVIEW/PORT ISABEL 89 73 88 74 / 0 10 10 20
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.BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. &&
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SHORT TERM...65-Irish LONG TERM....56-Hallman AVIATION...56-Hallman
NWS BRO Office Area Forecast Discussion