textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 550 PM CDT Fri May 15 2026

Key Messages:

* A Small Craft Advisory on the Laguna Madre is in effect through 1 AM Saturday. Small Craft Exercise Caution headlines are likely to continue into early next week across the Lower Texas coastal waters. Another Small Craft Advisory is possible early next week.

* A Minor to Moderate Heat Risk (Levels 1 and 2 of 4) this weekend become a mostly Major Heat Risk (Level 3 of 4) this Sunday into next Tuesday.

* Heat Risks de-escalate throughout the remainder of next week as unsettled weather gradually increases chances of rain to as much as a low to medium (30-50%) chance.

* There is a Moderate Risk of rip currents through most of the weekend.

DISCUSSION

Issued at 1223 PM CDT Fri May 15 2026

A mid-level ridge is expected to be the main influence for the weather over Deep South Texas and the Rio Grande Valley through Tuesday. As such, we can expect very low rain chances (less than 10%) and above normal temperatures. While the high temperatures could be in the range of upper 90s to lower triple digits. The heat indices are expected to be in the range of 105-110 F during this period. This will result in a mixture of moderate (level 2 of 4) to major (level 3 of 4) heat risk for the region. The current forecast shows that the major heat risk is most likely to occur on Monday and Tuesday. While the current forecast does keep the heat indices below the criteria for Heat Advisory, it is possible that the forecast could change and for a Heat Advisory to be issued. An SPS for elevated heat indices could also be issued as well if the heat indices continue to be borderline to Heat Advisory as well.

By the end of the weekend and moving into early next week, an upper- level trough will start to move across the plains before moving back towards the north. This trough should push a frontal boundary into northern Texas and Southern Oklahoma by next Wednesday. Without the support of the upper level trough, the frontal boundary should stall out around that area. The upper-level trough should also push the mid-level ridge out of the region. Factoring in the southeasterly flow at the surface to bring in more moisture to the area. It is possible that some showers and thunderstorms could occur starting Wednesday and lasting through the end of the forecast period. While the current rain chances for Wednesday are low to medium (around 30- 40%), they do increase slightly for Thursday and next Friday to generally more medium (around 50%). Given that this part forecast still several days removed, it is possible that there could be further changes that come in as model trends could change further. Even without the rain, cloud coverage is expected to build over Deep South Texas and the Rio Grande Valley, so that will help reduce the heat a bit.

Meanwhile along the Lower Texas Coast, a moderate risk of rip currents is expected to carry through the majority of the weekend.

AVIATION

(00Z TAFS) Issued at 550 PM CDT Fri May 15 2026

MVFR to VFR will prevail at the aerodromes through the next 24 hours. Moderate to breezy winds with clear to partly cloudy skies are also anticipated.

MARINE

Issued at 1223 PM CDT Fri May 15 2026

As the pressure gradient tightens over the Lower Texas Coast, Small Craft Advisory is in effect this afternoon and through tonight due to sustained southeasterly winds around 20 knots with gusts up to 25 knots possible. While the seas are expected to be moderate at this time. Conditions are expected to remain adverse for the majority of the period, thus Small Craft Exercise Caution headlines are likely for the majority of the time. The pressure gradient is expected to tighten again during the early part of the work week, which could result in hazardous conditions as winds and seas become elevated. Thus a high likelihood of another Small Craft Advisory being needed.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 76 91 80 93 / 0 10 0 0 HARLINGEN 72 92 78 94 / 0 10 0 0 MCALLEN 75 95 79 96 / 0 0 0 0 RIO GRANDE CITY 73 97 78 99 / 0 0 0 0 SOUTH PADRE ISLAND 78 84 80 85 / 0 10 0 0 BAYVIEW/PORT ISABEL 76 90 79 91 / 0 10 0 0

BRO WATCHES/WARNINGS/ADVISORIES

TX...None. GM...Small Craft Advisory until 1 AM CDT Saturday for GMZ130-132-135.