Port Mansfield, TX to the Rio Grande River 20 - 60 NM Marine Forecast
| Today...Southeast Winds Around 5 Knots, Becoming East This Afternoon. Seas 2 To 3 Feet. Wave Detail: Southeast 2 Feet At 5 Seconds And Southeast 2 Feet At 8 Seconds. A Slight Chance Of Showers And Thunderstorms. |
| Tonight...East Winds 10 To 15 Knots, Diminishing To 5 To 10 Knots Early In The Morning. Seas 2 To 3 Feet. Wave Detail: Southeast 3 Feet At 5 Seconds And East 1 Foot At 8 Seconds. A Slight Chance Of Showers And Thunderstorms After Midnight. A Chance Of Showers And Thunderstorms Early In The Morning. |
| Thursday...East Winds 5 To 10 Knots. Seas 2 To 4 Feet. Wave Detail: East 3 Feet At 6 Seconds And East 1 Foot At 9 Seconds. A Chance Of Showers And Thunderstorms. |
| Thursday Night...East Winds 10 To 15 Knots. Seas 3 To 4 Feet. Wave Detail: East 4 Feet At 6 Seconds. A Chance Of Showers. |
| Friday...East Winds 10 To 15 Knots. Seas 3 To 5 Feet. Wave Detail: East 4 Feet At 7 Seconds. A Chance Of Thunderstorms In The Morning. A Chance Of Showers. A Slight Chance Of Thunderstorms In The Afternoon. |
| Friday Night...East Winds 10 To 15 Knots, Diminishing To 5 To 10 Knots After Midnight. Seas 4 To 5 Feet. Wave Detail: East 4 Feet At 7 Seconds. A Slight Chance Of Showers And Thunderstorms In The Evening, Then A Chance Of Showers And Thunderstorms After Midnight. |
| Saturday...East Winds Around 5 Knots, Becoming 5 To 10 Knots In The Afternoon. Seas 3 To 5 Feet. A Slight Chance Of Thunderstorms. A Chance Of Showers Early In The Morning, Then A Slight Chance Of Showers In The Afternoon. |
| Saturday Night...East Winds Around 10 Knots, Becoming Southeast After Midnight. Seas 3 To 4 Feet. A Slight Chance Of Showers And Thunderstorms Early In The Morning. |
| Sunday...Southeast Winds 5 To 10 Knots, Becoming East In The Afternoon. Seas 2 To 3 Feet. A Slight Chance Of Showers And Thunderstorms Until Late Afternoon. |
| Sunday Night...East Winds Around 10 Knots, Becoming Southeast After Midnight. Seas 2 To 3 Feet. A Slight Chance Of Showers And Thunderstorms After Midnight. Winds And Seas Higher In And Near Thunderstorms. |
| Area Forecast Discussion ...UPDATED National Weather Service Brownsville TX 1243am CDT Wednesday September 16 2026 Issued at 1041pm CDT Tuesday September 15 2026 The first focus of the forecast remains the brutal, near record triple digit heat expected again on Wednesday as ridging aloft and plentiful sunshine soars temperatures to around 6-8 degrees above average and enhancing moisture causes heat indices to max out around 105-111 F across the region, with extreme risks of heat- related illnesses expected across most of the RGV/Rio Grande Plains and a major heat risk elsewhere. Once again, a SPS is in effect on Wednesday across the lower and mid RGV, not including the barrier islands, for heat indices of 108-111 F, possibly briefly hotter. The second focus is the anticipated unsettled weather brought in by a slight weather pattern change; a 1020-1030 mb surface high over the East Coast spills southwestward to the Gulf and transitions winds to easterly by Wednesday morning, gusting to near 20-25+ mph in the afternoon. This will aid in advecting inland deep Gulf moisture associated with a developing shortwave trough along the southern periphery of a retreating high pressure aloft, moistening PWAT (Precipitable Water) values throughout Wednesday, peaking as high as 2.0-2.4+ in. Wednesday night into Friday before gradually drying throughout the later half of Friday; chances of rain along the daytime seabreeze boundary increase from a low (10-15%) chance across the lower and mid Rio Grande Valley on Wednesday to a region-wide low to medium (30-60%) and 20-50% chance on Thursday and Friday, respectively. Total forecast rainfall amounts Thursday into Friday have trended down, only expecting up to 0.20 of an inch. However, given such high moisture content, heavy downpours and some localized minor flooding are possible, particularly within any slower-moving or training of thunderstorms on Thursday and possibly Friday, which could quickly drop half an inch or more of rain. Increased cloud coverage Thursday and Friday, followed by drier air funneling into the region as ridging resumes over the weekend, should help cool off temperatures to mostly the upper 90s by Thursday, which is still around 5 degrees above average, as well as improve heat risks from moderate to major on Thursday to mostly moderate Friday into Saturday. Yet, moisture and temperatures could rebound towards the end of the weekend, leading to moderate to major heat risks with additional SPSs for heat are possible by Sunday. Low to medium chances of rain return next week, potentially knocking down temperatures and improving heat risks again. Marine Issued at 1041pm CDT Tuesday September 15 2026 Gentle to moderate southeasterly winds become northeasterly to easterly on Wednesday and easterly to southeasterly again over the weekend. Slight to moderate (2-4 ft) seas build to moderate (3-5 ft) Thursday before improving back to slight to moderate by Sunday. Low to medium (20-40%) chances of rain on Wednesday increase to a medium to likely (40-70%) chance on Thursday followed by a low to medium (20-50%) chance on Friday and Saturday. Chances of rain continue into next week as well. NOAA Brownsville TX Office: Watches - Warnings - Advisories None. |
Brownsville TX Radar
Gulf Radar