Area Forecast Discussion
Issued by NWS Brownsville, TX
Issued by NWS Brownsville, TX
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304 FXUS64 KBRO 250851 AFDBRO Area Forecast Discussion National Weather Service Brownsville TX 351 AM CDT Wed Sep 25 2024 ...New SHORT TERM, LONG TERM, MARINE... .SHORT TERM... (Today through Thursday) Issued at 349 AM CDT Wed Sep 25 2024 An upper level trough over the eastern US looks to develop a closed low over the Central Mississippi River Valley by tonight. Forcing associated with this system will support a cold front dropping south from Central Texas and moving through the CWA late tonight into early Thursday morning. PWAT values above 1.5 inches and CAPE values around 1000 J/kg ahead of the front could support showers and thunderstorms developing ahead of and along the front. HiRes models are showing some isolated seabreeze convection this afternoon, then a line of scattered thunderstorms developing along the cold front tonight. Ample shear and instability may be present to support some of these thunderstorms becoming strong to severe. The SPC day one outlook has a marginal risk for northern Kenedy County through 7 am Thursday. High temperatures this afternoon are expected to reach the low to mid 90s, with heat indices topping out around 105 to 108. The spatial coverage of the higher heat indices looks to remain low enough not to warrant a Special Weather Statement this afternoon. Low temperatures tonight are expected to fall to the low to mid 70s. High temperatures Thursday are expected to top out in the upper 80s to low 90s. Drier air behind the front is expected to keep heat index values below 100. Lastly, swell from Tropical Storm Helene is expected to arrive Thursday along the Lower Texas Coast. This will likely lead to a higher risk of rip currents and some minor coastal flooding at area beaches. && .LONG TERM... (Thursday night through Tuesday) Issued at 349 AM CDT Wed Sep 25 2024 The forecast period starts with a 500mb low centered over the Middle Mississippi River Valley and a mid-level ridge located over New Mexico. The aforementioned deep layer trough will begin to absorb the remnants of Helene as the 500mb trough/low lingers over the Middle Tennessee Valley and the Appalachians through the weekend as the mid-level ridge remains centered near the Four Corners. At the surface, much drier air will continue filter into the region in the wake of the front. Hurricane Helene is forecast to make landfall around the Florida Big Bend region by late Thursday evening. Please refer to the latest forecast by the National Hurricane Center for the latest information on Hurricane Helene. The combination of the Thursday`s frontal passage and the arrival of long period swell from Helene will result in increased wave heights and adverse ongoing beach conditions Thursday night into Friday. An enhanced rip current risk and minor coastal flooding will be possible at beaches along the Lower Texas Coast Thursday night into Saturday. Near to above normal high temperatures will prevail through the period with highs in the low to mid 90s, except for the 80s at the beaches. Drier air will keep heat indices below 100 degrees and will support a minor heat risk through the period. Overnight lows will feel rather comfortable with below normal temperatures and slightly drier air expected through the weekend. && .AVIATION... (06Z TAFS) Issued at 1233 AM CDT Wed Sep 25 2024 Predominantly VFR conditions are expected through the period. Some isolated to scattered showers and thunderstorms are possible late this morning and this afternoon. Any showers or thunderstorms that move over an airfield may briefly drop conditions to MVFR levels. && .MARINE... Issued at 349 AM CDT Wed Sep 25 2024 Today through Thursday...Generally favorable marine conditions are expected through tonight, as winds remain light to moderates with slight seas. Winds look to pick up out of the north early Thursday morning with the passage of a cold front. Additionally, seas will increase thanks to the combination of stronger winds associated with the cold front, and the arrival of swell from Tropical Storm Helene Thursday afternoon. As such, Small Craft Should Exercise Caution headlines will likely be needed Thursday for the Gulf waters. Thursday night through Tuesday...Swells from Hurricane Helene and the passage of a cold front will likely lead to lingering adverse conditons at the start the period. Ongoing Small Craft Should Exercise Caution conditions or Small Craft Advisories may continue for the Gulf waters Thursday night into Friday with wave heights between 6-7 feet. Seas are expected to subside over the weekend, with favorable conditions prevailing through the remainder of the period. && .PRELIMINARY POINT TEMPS/POPS... BROWNSVILLE 91 76 88 70 / 40 20 30 0 HARLINGEN 92 73 89 65 / 30 20 20 0 MCALLEN 97 76 94 70 / 20 30 10 0 RIO GRANDE CITY 95 74 91 67 / 20 30 10 0 SOUTH PADRE ISLAND 87 79 86 76 / 40 30 30 10 BAYVIEW/PORT ISABEL 90 75 86 70 / 30 20 20 0 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ SHORT TERM...60-BE LONG TERM....63-KC AVIATION...60-BE