textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 611 AM CDT Thu May 14 2026

Key Messages:

* Moistening relative humidity levels increase Minor Heat Risks (Level 1/4) to a Moderate (Level 2/4) Heat Risk by Saturday afternoon.

* A Major Heat Risk (Level 3/4) is possible early next week along/east of I-69 E.

* The potential for unsettled weather may increase chances of rain to as much as a low to medium (20-40%) chance later this weekend and into next week.

* A low risk of rip currents continues through Thursday afternoon, likely to become a moderate risk by this weekend as southeasterly winds enhance.

* Breezy to gusty winds are expected to lead to Small Craft Exercise Caution headlines beginning Thursday afternoon.

DISCUSSION

Issued at 1025 PM CDT Wed May 13 2026

High pressure aloft slowly shifts east across Mexico and to the western Gulf through this week, maintaining mostly sunny skies and dry conditions across Deep South Texas into this weekend. Meanwhile, a mid/upper level trough remains parked over the southwestern US and northwestern Mexico, creating a persistent area of low pressure over the Plains and the Sierra Madre. Pressure falls interacting with a surface high over the Gulf will result in breezy southeasterly winds, likely gusting up to 20-30+ mph each afternoon, highest along/east of US-281. Later this weekend, troughing begins to take over aloft, potentially sparking daily rounds of convection over the Sierra Madre in the afternoon or evening, bringing as much as a low to medium (20-40%) chance of showers and thunderstorms each night along/west of US-281, beginning on Sunday. Enhanced forcing and possible shortwaves aloft may help to expand chances of rain across the region by the middle of next week, though also a 20-40% chance at this time.

While temperatures are currently anticipated to remain near normal, rising to the low/mid 90s further east and mid/upper 90s further west, PWAT values hike and peak over the weekend/next week as a surface high pressure shifting towards the southeastern US and strengthening low pressure systems over the Plains transport deeper, more tropical, Gulf moisture northwestward into our region. So, factoring in relative humidity, maximum afternoon apparent temperatures are likely to gradually rise over the weekend from 95-100 F on Friday to 105-110 F by Sunday, even warming by a few degrees through the early parts of next week. At this time, we expect a Minor Heat Risk to elevate to a Moderate Heat Risk by Saturday as well as a Major Heat Risk developing along/east of I-69 E by Monday into Tuesday. Special Weather Statements and/or Heat Advisories are possible, especially early next week. Increased cloud coverage could help to alleviate some of the heat as next week progresses. Overnight conditions gradually become warmer, muggier and breezier, warming from the 60s/70s tonight and Thursday night to as warm as the 70s/80s by Saturday night, which is near 5-10 degrees above average.

A low risk of rip currents prevails through Thursday afternoon though is likely to become a medium risk by the weekend after as southeasterly winds enhance.

AVIATION

(12Z TAFS) Issued at 611 AM CDT Thu May 14 2026

VFR conditions are expected to generally prevail through the TAF period with some patchy fog, mainly near HRL, potentially reducing visibility over the next hour or two. Expect a southeasterly breeze this afternoon.

MARINE

Issued at 1025 PM CDT Wed May 13 2026

Small Craft Exercise Caution headlines are likely to return Thursday afternoon as a tightening pressure gradient strengthens southeasterly winds to mostly moderate to fresh, strong at times while slight (1-2 ft) seas build to moderate (3-6 ft, occasionally higher). There is a low to medium (20-40%) chance of showers and thunderstorms next week.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 90 74 90 76 / 0 0 0 0 HARLINGEN 92 70 92 72 / 0 0 0 0 MCALLEN 95 72 94 75 / 0 0 0 0 RIO GRANDE CITY 94 70 95 73 / 0 0 0 0 SOUTH PADRE ISLAND 83 77 83 78 / 0 0 0 0 BAYVIEW/PORT ISABEL 89 74 89 76 / 0 0 0 0

BRO WATCHES/WARNINGS/ADVISORIES

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