textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 1221 AM CDT Fri Aug 14 2026

- Major to extreme risks (levels 3/4 and 4/4) of heat-related illnesses on Friday gradually improve to a mostly moderate risk (level 2/4) by Sunday, before gradually deteriorating to a major risk by the middle of next week.

- A Special Weather Statement (SPS) is in effect for Starr, Hidalgo and Brooks as well as the coastal and inland portions of Cameron, Willacy and Kenedy counties on Friday for heat indices of 108-111+ F.

- Aside from a low (15-20%) chance of rain along the seabreeze boundary on Friday and next Monday afternoon, conditions are likely to remain dry.

- The combination of breezy and mostly dry weather coinciding with low afternoon minimum relative humidity values brings a continued risk of fire weather into next week.

- A medium risk of life-threatening rip currents prevails tonight through Friday afternoon.

DISCUSSION

Issued at 1040 PM CDT Thu Aug 13 2026

A mid-level high pressure continues building over the Deep South, gradually shifting west and raising heights across the Southern Plains into this weekend. The procession of mid/upper level shortwave troughs translating over the Plains leads to another brutally hot day on Friday as southeasterly to south-southeasterly winds, gusting to around 25-35+ mph, pump heat and Gulf moisture inland, resulting once again in a major to extreme risk of heat- related illnesses across most of deep south Texas on Friday. A SPS is in effect for Brooks, Starr and Hidalgo as well as the inland and coastal portions of Kenedy, Willacy and Cameron counties on Friday for afternoon heat indices of 108-111 F, or a few degrees warmer, generally occurring within the hours of 12 PM to 5 PM. The only temporary relief on Friday could be from a weak inverted trough passing aloft, possibly generating a low (15-20%) chance of rain from isolated to scattered showers and thunderstorms, passing east-to-west, along the seabreeze boundary during the afternoon and early evening hours.

As the ridge extends further west and flattens this weekend into next week, the pressure gradient relaxes just a bit and a surface high pressure settles just offshore the central Gulf coast, transitioning and weakening winds to mostly east-southeasterly with gusts of 15-25+ mph by Saturday, causing heat risks to gradually improve to mainly moderate, with pockets of major, from Sunday through next Tuesday along with 105-110 F maximum heat indices. This should also help to cool high temperatures by a few degrees, with lower 100s (100-103 F) peeling back to along/west of I-69 E this weekend into the beginning of next week, while mid 100s (104-106 F) persist across the Rio Grande Plains and mid/upper 80s continue along/near the Lower Texas Gulf coast. However, a warming trend ensues towards the middle of next week as the high pressure aloft slowly migrates eastward and the surface high shifts southward to the central Gulf, bringing back nearly widespread inland highs in the low/mid 100s and worsening risks of heat-related illnesses to mostly major by the middle to later parts of next week. Aside from another weak inverted trough passing over on Monday, bringing a low (15-20%) chance of rain along the seabreeze boundary to the lower and mid RGV, dry conditions prevail though an isolated shower or two is possible most days along the seabreeze. While Heat Advisories are not anticipated at this time, additional SPSs are possible. Overnight lows in the upper 70s/low 80s continue.

Fire weather concerns prevail into next week as well, particularly during the afternoon hours, when 20-foot winds of around 10-15+ mph, gusting to 20-30+ mph (up to 35+ mph on Friday), coincide with relative humidity minimizing around 25-50 percent, driest furthest west/northwest and vice versa.

A moderate risk of life-threatening rip currents continues tonight through Friday afternoon.

AVIATION

(06Z TAFS) Issued at 1221 AM CDT Fri Aug 14 2026

Predominately VFR conditions are forecast to continue through the TAF period. There is a low chance for isolated convection along the sea breeze Friday afternoon. If any showers or thunderstorms develop and move over an airfield, ceilings and visibilities may briefly drop to MVFR levels. Winds are forecast to remain out of the southeast through the period, with wind speeds and gusts increasing through the afternoon.

MARINE

Issued at 1040 PM CDT Thu Aug 13 2026

Although a Small Craft Advisory continues across the Laguna Madre and the Nearshore Gulf waters (0-20 nm) until 1 AM Friday (tonight) for southeasterly to southerly winds of around 20 knots, gusting to 25 knots, marine conditions gradually improve throughout the remainder of tonight as southeasterly to southerly winds decrease to moderate to fresh by Friday morning with moderate (3-5 ft) seas. Periods of Small Craft Exercise Caution (SCEC) headlines are likely Friday through Friday night before gentle to moderate, occasionally fresh, southeasterly winds and slight to moderate (2-4 ft) seas resume on Saturday. SCEC conditions may return by the middle to later part of next week. Otherwise, aside from a low (15-30%) chance of rain late tonight through Friday afternoon and again Sunday into Monday, conditions are anticipated to remain dry.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 97 82 97 80 / 20 10 0 0 HARLINGEN 100 79 100 77 / 20 0 0 0 MCALLEN 102 82 103 81 / 20 0 0 0 RIO GRANDE CITY 103 80 103 78 / 20 0 0 0 SOUTH PADRE ISLAND 90 82 89 81 / 20 0 0 0 BAYVIEW/PORT ISABEL 96 80 95 79 / 20 0 0 0

BRO WATCHES/WARNINGS/ADVISORIES

TX...None. GM...Small Craft Advisory until 1 AM CDT early this morning for GMZ130-132-135-150-155.