FXUS64 KBRO 190344 AFDBRO Area Forecast Discussion National Weather Service Brownsville TX 1044 PM CDT Mon Aug 18 2025 ...New DISCUSSION, MARINE... .DISCUSSION... Issued at 1040 PM CDT Mon Aug 18 2025 The mid-level ridge continues to retreat into the Four Corners by late week, as Hurricane Erin swings by the US East Coast. This leaves weaker pressure at 500mb along the western Gulf. Moisture builds through the weekend into early next week as a weak coastal low and trough persist along the lower Texas coast. This helps set up multiple rounds of beneficial rainfall each day through the forecast period, especially Wednesday through Sunday. Overall, there does not appear to be much flow at the surface, leaving the sea breeze to be the main catalyst for initial convection and meandering or colliding outflow boundaries helping to spread the coverage. Slower moving storms with abundant moisture also increases the flooding rain threat. At the moment, WPC has kept a Marginal Risk (level 1 of 4) of excessive rainfall mainly north of the CWA Thursday and Friday, barely reaching into Zapata County. Several CAMs were hinting at strong thunderstorms working southwest across the ranchlands and into the brush country or upper valley late Tuesday afternoon into Tuesday evening. The guidance has diminished the threat some this evening, but would be something to monitor. As the week progresses, abundant cloud cover and better rain chances limit peak heating and stifle instability. Temperatures remain near normal and hot Tuesday, with highs gradually dropping a degree or two each day through the forecast period and lows remaining warm. Expect a Moderate (level 2 of 4) Heat Risk each day. Patchy shallow fog or field fog may develop each night and early morning, especially across the eastern ranchlands and coastal counties. && .AVIATION... (00Z TAFS) Issued at 632 PM CDT Mon Aug 18 2025 VFR conditions are expected to generally prevail through the TAF period, with southeasterly winds diminishing overnight. Patchy shallow fog may develop, especially near HRL, late tonight with confidence too low at this time to include in this TAF package. && .MARINE... Issued at 1040 PM CDT Mon Aug 18 2025 With generally weak flow across coastal waters, expect generally favorable marine conditions through the forecast period. The chance of showers and thunderstorms persists offshore into next week, working closer to the coast each night and early morning. && .PRELIMINARY POINT TEMPS/POPS... BROWNSVILLE 95 79 95 78 / 10 0 20 20 HARLINGEN 98 74 97 74 / 10 0 20 20 MCALLEN 102 79 102 78 / 10 0 20 10 RIO GRANDE CITY 103 77 103 78 / 0 0 10 20 SOUTH PADRE ISLAND 88 80 88 80 / 10 0 10 20 BAYVIEW/PORT ISABEL 92 77 92 77 / 10 0 10 20 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ SHORT TERM...56-Hallman LONG TERM....56-Hallman AVIATION...56-Hallman