textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 1207 PM CDT Sun Jun 28 2026

- Afternoon heat indices of around 105-110 F maintain mostly moderate heat risks (level 2 of 4) through tomorrow though inland portions of the coastal counties are likely to experience major heat risks (level 3 of 4) today. Minor (level 1 of 4) to moderate heat risks are likely by Tuesday.

- Mainly dry conditions prevail with only a low (at most, 15%) chance of rain on Thursday.

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

- A Small Craft Advisory is in effect for the Laguna Madre and northern Gulf waters (northward from Port Mansfield 0-60 nm out) until 7 AM Monday morning.

DISCUSSION

Issued at 1207 PM CDT Sun Jun 28 2026

Mainly dry conditions (PoPs <10%) are expected across deep south Texas through most of the forecast as our region remains wedged between persistent troughing and high pressure aloft over the western and eastern US, respectively. The only potential low (at most, 15%) chance of rain may be on Thursday from a possible weak low pressure system moving over the Bay of Campeche, causing PWATs to briefly rise above average Thursday into Friday. An isolated shower or two can't be ruled out over the weekend as well. In the meantime, breezy conditions continue today into tomorrow, with southeasterly winds gusting to 25-30+ mph, in response to pressure falls over the Southern Plains and the Sierra Madre. Resulting enhanced moisture advection off the Gulf is expected to result in mainly moderate heat risks through tomorrow as afternoon heat indices peak around 105-110 F, though some areas across the inland portions of the coastal counties could experience major heat risks this afternoon. The pressure gradient and winds are anticipated to ease a bit tomorrow night, slightly lowering apparent temperatures to around 100-105 F with minor to moderate heat risks from Tuesday into the later parts of the week while actual daytime air temperatures continue rising to the mid/upper 90s (upper 90s/low 100s across the Upper RGV) and mid/upper 70s overnight (lower 80s closer/along the coast). Weak high pressure may resume aloft next weekend, which could cause heat indices to near 105-110 F with mainly moderate heat risks.

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

AVIATION

(18Z TAFS) Issued at 1207 PM CDT Sun Jun 28 2026

VFR conditions with breezy to gusty southeasterly winds of around 15- 20 kt, gusting to 25-30 kt, are likely to continue for the 18Z TAF cycle, though may ease just a bit during the pre-dawn to early morning hours on Monday.

MARINE

Issued at 1207 PM CDT Sun Jun 28 2026

A Small Craft Advisory is in effect for the Laguna Madre and the northern Gulf waters (from Port Mansfield and northward 0-60 nm out) until 7 AM Monday morning, along with Small Craft Exercise Caution headlines elsewhere, as a tightened pressure gradient results in fresh to strong southeasterly winds and moderate (4-6 ft). Mainly moderate southeasterly winds and moderate (3-5 ft) seas are likely to resume by Monday night or Tuesday morning. Dry conditions prevail into at least the middle of the week, likely followed by low (around 15%) chances of rain later in the week and next weekend, possibly as high as a low (15-25%) chance on Thursday.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 81 94 80 94 / 0 0 0 0 HARLINGEN 79 97 77 96 / 0 0 0 0 MCALLEN 80 99 79 99 / 0 0 0 0 RIO GRANDE CITY 79 101 77 100 / 0 0 0 0 SOUTH PADRE ISLAND 81 87 81 87 / 0 0 0 0 BAYVIEW/PORT ISABEL 80 92 78 91 / 0 0 0 0

BRO WATCHES/WARNINGS/ADVISORIES

TX...None. GM...Small Craft Advisory until 7 AM CDT Monday for GMZ130-132-135- 155-175.