textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 1223 PM CDT Sun Sep 6 2026

- A Special Weather Statement (SPS) remains in effect today until 6 PM this evening across Southern Hidalgo County as well as the inland and coastal portions of Cameron, Willacy and Kenedy counties (not including the barrier islands) for heat indices of 108-111 F.

- Major to extreme risks of heat-related illnesses (levels 3/4 and 4/4) prevail through the forecast as afternoon heat indices continue to soar to 106-111+ F. Additional SPSs for heat are possible.

- Aside from a low to medium (20-40%) chance on Wednesday, daily low (15-20% or higher) chances of rain along the seabreeze boundary continue through potentially Thursday.

- A low risk of life-threatening rip currents continues through tomorrow afternoon.

DISCUSSION

Issued at 1223 PM CDT Sun Sep 6 2026

Weak inverted shortwave troughs riding along the southern periphery of a high pressure aloft, centered over the central and southern US, are expected to result in a daily low (15-25%) chance of isolated to scattered showers and thunderstorms along the afternoon and early evening seabreeze boundary across portions of deep south Texas through Tuesday, with the best chances of rain likely remaining along/east of US-281. Although convection is expected to be brief and passing in nature, some storms may be capable of producing heavy rain, frequent lightning and gustier winds, especially on Wednesday when chances of rain increase to a low to medium (20-40%). Chances of rain drop off from a low (15-20%) chance by Thursday to around 5-15%, more or less, by Friday as ridging and subsidence aloft return.

Considering the short duration of anticipated daily seabreeze activity, plentiful sunshine is still expected and southeasterly to southerly winds, gusting to 20-25+ mph, will maintain the hot airmass over the region, allowing temperatures to continue soaring to the lower 100s across most inland areas, though topping out around 104-107 F over the upper RGV and Rio Grande Plains (hotter further west), which is around 5-7 degrees above average. Factoring in the persistent onshore flow leading to Gulf moisture advection, additional SPSs are likely, especially across the easternmost counties: Kenedy, Willacy and Cameron. Altogether, nearly widespread areas of extreme risks of heat-related illness along/west of US-281 retreat to the upper RGV and Rio Grande Plains Tuesday through Friday before expanding back eastward over the weekend as a tightening pressure gradient enhances southeasterly winds and moisture content. Elsewhere, mostly major, with pockets of extreme, heat risks prevail.

A low risk of life-threatening rip currents continues through tomorrow afternoon.

AVIATION

(18Z TAFS) Issued at 1223 PM CDT Sun Sep 6 2026

Gentle to moderate southeasterly to southerly winds and slight to moderate (1-3 ft) seas increase and build to moderate to fresh winds and moderate (3-5 ft) seas this weekend as the pressure gradient tightens, likely resulting in periods of Small Craft Exercise Caution conditions. Daily low (15-20%) chances of rain continue, increasing to as much as a low to medium (20-60%) chance on Wednesday.

MARINE

Issued at 1223 PM CDT Sun Sep 6 2026

Southeasterly winds of around 10-15 kt, gusting to 20-25 kt, continue into early this evening before diminishing to light to gentle winds overnight. Although chances are too low to include within the TAFs at this time, there is a low (15-25%) chance of isolated to scattered showers and isolated thunderstorms impacting or occurring within vicinity of all aerodromes this afternoon, followed by clearing skies, with dry weather resuming tonight into tomorrow. Otherwise, VFR conditions should prevail.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 81 98 80 98 / 0 20 10 20 HARLINGEN 76 101 77 101 / 0 20 10 20 MCALLEN 80 103 81 103 / 20 20 0 10 RIO GRANDE CITY 79 103 79 103 / 10 10 0 10 SOUTH PADRE ISLAND 82 90 82 90 / 0 10 0 10 BAYVIEW/PORT ISABEL 79 96 78 95 / 0 20 0 20

BRO WATCHES/WARNINGS/ADVISORIES

TX...None. GM...None.