409 FXUS64 KBRO 011136 AFDBROArea Forecast Discussion National Weather Service Brownsville TX 636 AM CDT Wed Oct 1 2025
...New AVIATION...
.DISCUSSION... Issued at 1024 PM CDT Tue Sep 30 2025
Dry conditions continue across Deep South Texas today into tomorrow as an expanding mid-level high pressure over northern Mexico maintains riding aloft. Throughout tomorrow into Friday, an upper level trough begins to deepen across the Midwest, leading to the development of a mid-level low over the central Gulf Coast states, which is forecast to linger and bring an increased chance of unsettled weather. Beginning Friday morning, probabilities of showers and thunderstorms increase along the coast to generally a low to medium (20-50%) chance, persisting into next week, expanding inland each day along the seabreeze boundary throughout the morning, afternoon and early evening hours. Most days, PoP`s of 30% and higher are likely to be near, and east of, US-281/I-69 C, with the best chances along and east of I-69 E. The most widespread coverage over the weekend appears to be Saturday, possibly maximizing in coverage across the region at a low to medium (20-60%) chance by the afternoon before decreasing to a 20-40% chance into Sunday as ridging briefly re-enhances. There continues to be disagreement between each run of the GFS and ECMWF deterministic and ensemble forecasts with regards to PWAT values during this timeframe, but there is some consensus that generally a range of 1.3-1.6 or 1.7 inches is possible over the weekend, highest along the immediate coast, potentially increasing into the middle next week. Therefore, there exists the possibility of some heavy rain in the strongest of convection over the weekend, but the better chance for heavier rain may be towards the middle parts of next week.
Near to slightly above average high temperatures continue each afternoon, with mid 80`s near the coast, low to mid 90`s east of US- 281/I-69 C and mid to upper 90`s further west, falling to the 60`s and 70`s inland overnight, becoming mostly 70`s over the weekend. Lows around 80 degF continue at SPI. Mainly minor (level 1 of 4) heat risks continue throughout the forecast, though moderate (level 2 of 4) heat risks may be possible across portions of the Rio Grande Valley beginning next Monday as moisture and relative humidity increase.
A low risk of rip currents continues through Friday, becoming a moderate risk by Saturday as wave heights and periods increase.
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.AVIATION... (12Z TAFS) Issued at 633 AM CDT Wed Oct 1 2025
VFR will continue at the aerodromes through the next 24 hours, with light winds and clear to partly cloudy skies.
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.MARINE... Issued at 1024 PM CDT Tue Sep 30 2025
Light to gentle northeasterly to easterly winds and slight (1-2 ft) seas become gentle to moderate and easterly to southeasterly with slight to moderate (2-4 ft) seas over the weekend and into next week. Low chances of rain return on Thursday, increasing to generally a medium to likely (40-70%) chance, or higher, beginning Friday.
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.PRELIMINARY POINT TEMPS/POPS... BROWNSVILLE 91 73 92 73 / 0 0 10 10 HARLINGEN 94 68 93 69 / 0 0 10 0 MCALLEN 98 72 98 73 / 0 0 0 0 RIO GRANDE CITY 98 69 98 69 / 0 0 0 0 SOUTH PADRE ISLAND 87 79 87 79 / 0 0 10 20 BAYVIEW/PORT ISABEL 89 72 90 73 / 0 0 10 10
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.BRO WATCHES/WARNINGS/ADVISORIES...None.
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NWS BRO Office Area Forecast Discussion