textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 623 AM CDT Sat Aug 8 2026

- Low chances of rain continue along the afternoon and early evening seabreeze boundary, increasing from a (10-15%) chance on Saturday to a 15-30% chance on Sunday.

- Chances of rain mostly diminish by Monday and risks of heat- related illnesses gradually worsen from a minor to moderate risk (levels 1/4 and 2/4) over the weekend to major and extreme risks (levels 3/4 and 4/4) by the middle to later parts of next week.

- Special Weather Statements and Heat Advisories are likely next week as heat indices climb back to 108-112+ F.

- Fire weather concerns could return by the middle of next week as relatively low minimum afternoon relative humidity values coincide with gusty southeasterly winds and dry fuels remain abundant across the worsening drought over portions of deep south Texas.

DISCUSSION

Issued at 1029 PM CDT Fri Aug 7 2026

Overall, very weak mid/upper level shortwaves riding along a ridge of high pressure aloft are expected to continue passing over deep south Texas through the remainder of this weekend, supporting slightly enhanced daytime cloud cover along with a low (10-15%) chance of rain on Saturday and a low (15-30%) chance on Sunday along the afternoon and early evening seabreeze boundaries, mostly limited to the Lower and Middle RGV. There is a fair amount of agreement between the GFS, ECMWF, HRRR and the RRFS that PWAT values will most likely maximize on Sunday, rising to 1.9-2.2+ in. along the boundary and remain elevated overnight. Although mid-level moisture may be drier, thus lending to shorter-lasting pop-up convection, above average PWAT could still lead to additional areas of brief heavy rain, some gustier winds (up to as much as 30+ mph) and frequent lightning, with ponding on the roads, reduced visibility and cloud-to-ground lightning possible, particularly on Sunday. Thankfully and hopefully, this rain will continue to be beneficial, dropping anywhere from 0.5 to 1.0 inch, or a little more, in the deeper convection, as well as reduce temperatures slightly, with most inland areas rising to around 97-100 F, while lower 100s continue across the Rio Grande Plains and mid 80s along the coast. As moisture content builds over the weekend, minor to moderate risks of heat-related illnesses on Saturday become a mainly moderate risk on Sunday.

High pressure aloft begins to build over the eastern and northern Gulf throughout the latter half of this weekend, re-dominating and causing heights to rise by late Sunday night across the region, diminishing chances of afternoon seabreeze rain from 10-15% on Monday down to less than 10% by Tuesday and beyond. Decreased cloud cover will allow for widespread inland highs in the lower 100s (mid/upper 100s across the Rio Grande Plains and the Upper RGV) by Monday afternoon, gradually warming a few degrees throughout the week as high pressure aloft spans across the Deep South and Southern Plains. Additionally, the continued procession of shortwaves aloft over the Plains/Rockies and resulting tightening pressure gradient are progged to enhance moisture content across our region as southeasterly winds increase to around 15-20+ mph, with gusts to 25-35+ mph, by Monday as well.

This is expected to result in a couple of factors to consider next week. Rising dewpoint values are anticpated to worsen risks of heat-related illnesses from moderate, with pockets of major on Monday, to major heat risks with pockets of extreme by the middle to later parts of next week. SPSs and even Heat Advisories are likely again next week, especially by the later part of the week as heat indices rise to 108-111+ F. Although any rainfall received over the next 2 days will be welcomed, fire weather concerns could be possible again by the middle of next week as considerable low relative humidity values, minimizing around 25-50% each afternoon, coincide with gusty southeasterly winds. This comes in light of the fact that dry fuels remain abundant within the Moderate Drought (D1) across nearly half of the region, most concerning across portions of the Lower and Middle RGV, where there is now a Severe Drought (D2).

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

AVIATION

(12Z TAFS) Issued at 623 AM CDT Sat Aug 8 2026

VFR conditions are forecast to continue through the period. Light and variable to calm winds this morning are forecast to increase to around 10 knots out of the southeast by late morning, shifting easterly with the sea breeze this afternoon. Wind gusts may briefly increase with the sea breeze passage this afternoon. Winds are forecast to become light and variable to calm again overnight.

MARINE

Issued at 1029 PM CDT Fri Aug 7 2026

Gentle to moderate easterly to southeasterly winds and slight to moderate (1-3 ft) seas become moderate to fresh southeasterly winds, with moderate (3-5 ft) seas by Monday, when periods of Small Craft Exercise Caution conditions are possible due to a tightening pressure gradient. Short-fused Small Craft Advisories are possible by the middle of next week as southeasterly winds increase to fresh to strong as the gradient tightens further. Low to medium chances of rain over the weekend (20-40% chance on Saturday and 30-60% chance on Sunday) gradually decrease to less than 10% by Tuesday.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 95 79 95 80 / 10 10 20 0 HARLINGEN 97 75 96 76 / 10 0 20 0 MCALLEN 101 79 101 80 / 10 0 20 0 RIO GRANDE CITY 101 77 100 78 / 10 0 10 0 SOUTH PADRE ISLAND 88 80 88 81 / 10 10 10 0 BAYVIEW/PORT ISABEL 93 78 93 79 / 10 10 20 0

BRO WATCHES/WARNINGS/ADVISORIES

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