581 FXUS64 KBRO 261111 AAA AFDBRO Area Forecast Discussion...UPDATED National Weather Service Brownsville TX 511 AM CST Wed Nov 26 2025 ...New AVIATION... .KEY MESSAGES... Updated at 509 AM CST Wed Nov 26 2025 * Dangerous surf and some tidal run-up at the beach expected Wednesday afternoon. * Difficult boating conditions arrive Wednesday for Laguna Madre and the Gulf, continuing over the Gulf into Wednesday night. * Some welcome rain (showers and storms) late tonight and Wednesday along a front. Marginal (Level 1 of 5) Risk for severe thunderstorms tonight into Wednesday (large hail greatest threat). * Marginal (Level 1 of 4) Risk for Excessive rainfall tonight into Wednesday across Deep South Texas. Heavy rain resulting in localized nuisance flooding is possible. * Stronger front could arrive early Sunday with much cooler temperatures and dangerous surf/boating conditions returning. && .DISCUSSION... Issued at 1040 PM CST Tue Nov 25 2025 Drastic changes to the weather pattern that includes notably cooler temperatures, multiple coastal/marine hazards, and much needed rainfall in the form of showers and thunderstorms (some of which can be strong to severe) are expected to take place within the next 12 hours across Deep South Texas and the Rio Grande Valley. The latest sfc MSAS analysis showed the well advertised frontal boundary draped over Brush Country (i.e. Starr, Jim Hogg, and Brooks County) this evening with a strong to severe thunderstorm cell tracking over northwestern Zapata into south-central Webb County. Tonight through Wednesday: Through tonight, expect for shower and thunderstorm coverage to increase across Deep South Texas and the Rio Grande Valley as the aforementioned frontal boundary continues to gradually work its way southward into northeastern Mexico. Despite some capping per the 00z BRO sounding and weak flow aloft, mixed-layer (MLCAPE) values up to 1,500 J/kg and 0-6km bulk shear values between 30-40 kts will support a conditional threat for severe thunderstorms through tonight and into Wednesday morning with the main threat being large hail. The Storm Prediction Center (SPC) has placed all of Deep South Texas under a Marginal (Level 1 of 5) Risk for severe thunderstorms through tonight and into Wednesday morning. Heavy rainfall and the risk for some ponding/nuisance flooding will also be a concern as these storms are slow movers with highly efficient rainfall rates. The combination of rainfall chances, increased cloud coverage, and the fropa will result in a notable airmass change on Wednesday. Despite returning to near seasonable levels, temperatures on Wednesday will be 10-20F degrees cooler than on Tuesday with projected highs in the 70s most places to lower 80s across Cameron County. An enhanced pressure gradient associated with the frontal boundary will result in strong northeast winds with speeds as high as 25 mph and higher gusts developing after daybreak on Wednesday. These winds will result in hazardous coastal/marine conditions on Wednesday (see MARINE SECTION). Wednesday night through Saturday night: By Wednesday evening/night, any lingering showers should have come to an end with winds also becoming lighter leaving behind a pleasantly cooler night. Overnight low temps are progged to be in the 50s most locations to the 60s across Cameron County and areas along the coast. Dry, tranquil, and notably cooler weather will persist through Friday with highs in the 70s to lower 80s. Winds will shift out of the southeast on Friday marking the onset of warm air advection (WAA) into the region. That said, Saturday will feature highs returning into the 80s across the region. The warmer than normal temperatures will be brief, however, as another cold front approaches from the north Saturday-Saturday night. Saturday night through Wednesday: Saturday night into Sunday, forecast models are suggesting another cold front will sweep through Deep South Texas. Highs on Sunday will be near normal levels and notably cooler from Saturday. As cold air advection continues to build/increase over the region, some of the coldest air of the season is set to arrive Sunday night through Tuesday night. Sunday night, overnight lows are expected to fall into the 40s across the Ranchlands to the 50s along the Rio Grande Valley. Widespread 40s are expected Monday and Tuesday nights. Highs in the 60s are expected to take place Monday and Tuesday. By Wednesday, east- southeast flow will potentially begins the process of warmer air advecting into the region. Stratiform rain showers associated with the marine layer are also possible Saturday night through Tuesday especially areas closer to the coast. && .AVIATION... (12Z TAFS) Issued at 509 AM CST Wed Nov 26 2025 The cold front is working south from the ranchlands into the Rio Grande Valley this morning, with an increasing chance of showers and isolated thunderstorms. By late morning, the chance of rain diminishes and northeasterly winds increase, becoming breezy to windy into the evening. MVFR ceilings may persist into the early evening before improving from west to east tonight. && .MARINE... Issued at 1040 PM CST Tue Nov 25 2025 Hazardous marine conditions are expected to develop on Wednesday in response to an enhanced pressure gradient associated with a passing frontal boundary. Small Craft Advisory (SCA) conditions are expected on Wednesday into Wednesday night over the Laguna Madre and Gulf Waters. Small Craft Exercise Caution (SCEC) conditons are expected thereafter (Wednesday night into Thursday). Thursday night into Friday, marine conditions are expected to deteriorate once again with SCA conditions developing are early as Friday evening ahead of a second cold front. Hazardous marine conditions are expected to continue through Sunday. Marine conditions could then begin to improve Monday through Wednesday of next week. && .CLIMATE... Issued at 1229 PM CST Tue Nov 25 2025 The record/near record heat of the past week has pushed nearly all RGV locations into the top five warmest Novembers on record through the 24th. Those rankings may rise a bit higher after today (25th). With day/night averages only expected to drop close to the long-term normals, if not a touch above, Wednesday through Friday - and another 10 degree above average number for Saturday - we're locking in on another top-ten warmest finish for everyone when we count the numbers at the end of November. Sunday's now expected cool-down won't be enough to flip the script. Here are the rankings, and departure from the top, for available locations (with minimal missing data) through the 24th: Brownsville (since 1878): 76.3 degrees, #2, -0.8 degrees from #1 McAllen (since 1941): 76.9 degrees, #2, -1.1 degrees from #1 Harlingen (since 1912): 73.2 degrees, #6, -1.2 degrees from #1 Weslaco (since 1914): 74.6 degrees, #3, -1.3 degrees from #1 RGC (since 1897)*: 73.9 degrees, #4, -2.9 degrees from #1 && .PRELIMINARY POINT TEMPS/POPS... BROWNSVILLE 79 66 78 66 / 80 20 10 0 HARLINGEN 78 59 78 61 / 70 10 0 0 MCALLEN 78 61 78 64 / 60 10 0 0 RIO GRANDE CITY 76 56 76 61 / 60 0 0 10 SOUTH PADRE ISLAND 79 72 76 71 / 80 20 10 0 BAYVIEW/PORT ISABEL 79 65 78 66 / 70 10 0 0 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...High Rip Current Risk through late tonight for TXZ451-454-455. High Surf Advisory from 9 AM this morning to 8 PM CST this evening for TXZ451-454-455. GM...Small Craft Advisory until midnight CST tonight for GMZ130-132- 135-150-155-170-175. && $$ SHORT TERM...23-Evbuoma LONG TERM....23-Evbuoma AVIATION...56-Hallman