Area Forecast Discussion
Issued by NWS Brownsville, TX
Issued by NWS Brownsville, TX
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201 FXUS64 KBRO 021725 AFDBRO Area Forecast Discussion National Weather Service Brownsville TX 1225 PM CDT Tue Jul 2 2024 ...New AVIATION... .SHORT TERM... (Today through Wednesday) Issued at 337 AM CDT Tue Jul 2 2024 500 mb high pressure, centered over the Gulf Coast states, will remain the dominant weather feature over the BRO CWFA through the period. This will produce rain-free conditions across Deep South Texas, the Rio Grande Valley, and the adjacent coastal waters. Temperature-wise, with the presence of the aforementioned mid-level high, daytime highs and overnight lows will be in the slightly above normal range. Despite relatively robust atmospheric moisture (precipitable water values more or less around 2 inches), heat indices will not reach established HEAT ADVISORY criteria. As a result, will mention heat index values in a SPECIAL WEATHER STATEMENT today and likely again tomorrow. && .LONG TERM... (Wednesday night through Monday) Issued at 337 AM CDT Tue Jul 2 2024 Key Message: * All eyes on Beryl and its future track and potential impact in the southwestern/western Gulf this weekend. The long term continues to be a tale of two forecasts: The easy...then the hard. Beginning with the easy (Wednesday night through Friday night): The dominant and seasonably strong 500 mb ridge remains anchored from west to east along 30-35N latitude, stretching from southern California through nearly all of Texas and east through the southern U.S.through Friday. This will maintain weak surface ridging across the northern and eastern Gulf with general south to southeast flow between it and the typical west Texas through the lee of Sierra Madre trough, keeping slightly above seasonal average temperatures by day and night with no rainfall. The "hard" begins Saturday and continues through Monday. All eyes will be on Beryl, as well as the evolution of the aforementioned ridging. Over the past few runs, the global and some of the hurricane models have been trending for a slightly deeper trough to develop and dig across the central and even the southern Plains into the Mississippi Valley, splitting the strong ridge in two, with the western portion retrograding to California while the eastern portion slides to the southeast U.S. coast. This morning`s early models follow their deterministic biases...with the ECMWF with higher heights and a more southern track into Mexico, but the GFS now a bit farther north, just off of the Lower Texas coast by late this weekend. The Canadian GEM has "flopped" back to a more southern track...owing to a stronger steering ridge. Hurricane models and the extrapolated consensus of them suggest a much closer approach toward the mouth of the Rio Grande/northeastern Tamaulipas on Sunday. Bottom line? A lot of uncertainty remains, and confidence remains low in exactly how the latter half of the Fourth of July weekend plays out. Here`s what we know this morning: * Beryl will weaken across the western Caribbean and along its track through the Yucatan...assuming it still crosses a good portion of it and doesn`t clip the northern end of it. Wind shear will do the job, and the current forecast brings Beryl down to a Tropical Storm when re-emerging over the Bay of Campeche. * The aforementioned digging trough into the central/southern Plains is becoming a bigger factor in forecast trends, and Beryl is more likely to "feel" it than not. That will cause at least a northwest movement by Saturday or Sunday, keeping the Valley in play for at least some potential impacts. What we still don`t know is how the wind shear profile will evolve over the southwest/western Gulf five days from now. Weaker shear would allow at least modest restrengthening; stronger shear would keep the future Beryl more susceptible to weakening. We also don`t know whether Beryl will expand much more in size during this period. Through the Caribbean trek and into the Yucatan, the cyclone will remain rather compact...and compact cyclones are more susceptible to disruptions from wind shear and dry air. For now...the sensible weather forecast remains largely the same for Saturday through Monday, with modest increases in rain chances and slight downward nudges in temperatures. The Weather Prediction Center`s deterministic QPF was knocked down to limit rainfall generally along/east of IH-69C, and total rainfall generally below 1 inch (with locally higher amounts). At minimum, we`ll see another round of dangerous surf and rip currents for average to poor swimmers, as well as some tidal run-up. At maximum? We just can`t say yet...but there is certainly a non- zero chance of much more rain, stronger winds, notable coastal flooding, and life-threatening surf. Hopefully, the steering setup becomes consistent in the next couple of days and we`ll have a better idea...and confidence...on the track. Regardless...keep those preparedness plans on the front burner and be ready to begin actions as soon as the Fourth. && .AVIATION... (18Z TAFS) Issued at 1225 PM CDT Tue Jul 2 2024 VFR and south to southeast winds around 10 to 15 knots will prevail through the forecast period at all TAF sites. There is a low potential for intermittent MVFR ceilings late tonight into early tomorrow morning, but confidence is too low to warrant a mention in the TAF at this time. && .MARINE... Issued at 337 AM CDT Tue Jul 2 2024 Today through Wednesday...Buoy 42020 reported south winds around 14 knots gusting to around 16 knots with seas slightly under 4.5 feet with a period of 8 seconds at 1:50 CDT/6:50 UTC. High pressure over the western Gulf of Mexico will produce light to moderate winds and low to moderate seas along the Lower Texas Coast through the period. Small Craft Should Exercise Caution and Small Craft Advisory are not anticipated to be needed. Wednesday Night through Friday Night...High pressure across most of the Gulf will keep conditions fairly copacetic...with moderate southeast winds and slight to moderate seas with no appreciable rainfall. Saturday and Saturday Night...Much will depend on the evolution of Beryl (size, strength, forward motion, etc.). For now, we`ve held onto seas building to 4 to 6 feet with the arrival of the swell train. Model forecasts suggest wave period could rise quickly to 12-14 seconds, which could generate wave heights up to 8-9 feet by Saturday night. Winds could also begin to pick up across the Gulf waters and reach 20+ knots at night...and the conditions and future forecast will depend on any Tropical Watch/Warning disposition at that time. Should the cyclone near the waters, the associated rain squalls would arrive as well. Small craft operators as well as shippers should stay updated daily on the trends with Beryl and plan accordingly. && .PRELIMINARY POINT TEMPS/POPS... BROWNSVILLE 95 80 94 82 / 0 0 0 0 HARLINGEN 96 77 96 77 / 10 0 10 0 MCALLEN 98 80 98 80 / 0 0 0 0 RIO GRANDE CITY 97 78 98 79 / 0 0 0 0 SOUTH PADRE ISLAND 88 83 89 84 / 0 0 0 0 BAYVIEW/PORT ISABEL 93 79 93 80 / 0 0 0 0 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ SHORT TERM...99 LONG TERM....99 AVIATION...22-Garcia