textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 552 PM CDT Sat May 30 2026

* Favorable beach conditions through Sunday night gradually worsen through the week, as easterly swell increases rip current intensity to potentially high Wednesday-Friday, with a low (10-20%) probability of tidal run-up toward the dunes Thursday and Friday, along with better opportunies for rain and some lightning, which could impact larger post-graduation crowds

* Favorable Gulf boating conditions through Monday, before easterly swell begins increasing by mid-week and could peak Thursday...along with a potential for more frequent rain with some lightning Tuesday through Thursday

* Rain-free conditions with seasonable end of May/early June heat through Sunday night.

* More unsettled conditions begin to arrive Monday and continue through Saturday, with isolated to scattered showers and thunderstorms along/near the coast each morning developing inland each afternoon. No significant rainfall or flooding is expected.

DISCUSSION

Issued at 110 PM CDT Sat May 30 2026

This afternoon through Sunday Night: The close of May and start of June will be quite nice, with clean skies under light to moderate east- southeast winds and seasonable temperatures (low to mid 90s each afternoon populated Valley, mid to upper 90s Brush Country/Rio Grande Plains) each afternoon and 70-75 each morning under mainly clear skies overnight with fair weather cumulus by day. Near perfect beach conditions as well, with inviting surf temperatures (low to mid 80s) and rip current intensity sliding back to low. About the only minor issue to watch is rural ground/field fog right around sunrise Sunday, with light winds and radiational cooling over the recent weeks moisture. Added a couple hours across these areas to account.

Monday through Tuesday: A developing/broadening plume of moisture in the west-central Gulf Sunday night, associated with a weak disturbance near/north of the Yucatan makes a bit of a westward jog Monday into Tuesday, as the 500 mb ridge that provided the dry weekend breaks down a little. A finger of this plume may edge across the lower Texas coast, with low level easterly flow activing the moisture a little bit with the afternoon sea breeze for isolated to perhaps scattered showers inland. Monday's chances/coverage are not impressive, but Tuesday shows a little more promise. That said, the enhanced moisture would only have minimal impact on high temperatures Tuesday..."dipping" to 2-4 degrees below average (lower 90s vs. mid 90s) for most.

Tuesday Night through Friday: Aloft, the 500 mb ridge gets pinched a bit by the continued southwest U.S. trough and now a strenghthening and dipping cutoff low along the southeast U.S. coast. That same pinched ridge expands northward behind this trough, and helps build a fairly strong surface high into the Ohio Valley, with the axis extending as far south as the northern Gulf coast. At the same time, weak but notable surface low pressure hangs across the southwest Gulf toward Yucatan, which increases the pressure gradient across the northern half of the Gulf, including toward the Texas coast. This is a textbook setup for a long-period moderate easterly swell to move across the central/western Gulf and create initially building surf and worsening rip current intensity.

Though predicted astronomical tides are modest...around the average wave run-up point...by mid week, the observed values are currently running 0.75 feet above predicted levels which has been shortening the beach a bit lately. A push from a building easterly swell could be sufficient to push observed values 1 foot or so above predicted, which combined with increased wave period would be sufficient to run tides up closer to the dunes.

Weather-wise, uncertainty increases with outcomes. Recently arriving models suggest the aforementioned ridge nudges eastward in time, which would allow a bit more deeper moisture to arrive on southwest flow aloft beginning Thursday and continuing through Saturday. That said, there are no strong waves to suggest any "Sierra Slammer" (west to east-moving squalls) during this period...so forcing would be a combination of general weak southwest flow aloft with any residual moisture from the central/west central Gulf "blob" and sea breeze interactions. NBM/WPC are genereally bearish on overall rainfall for this window, with ~0.10" in the deterministic window and probabilities for 0.5 to 1" generally at or below 50% (mostly 20-40%).

That said, increased cloud cover and even modest afternoon shower coverage can help nudge down forecast highs, and that's what happens with a continuation of 2-5 degree below early June averages for this period.

AVIATION

(00Z TAFS) Issued at 552 PM CDT Sat May 30 2026

Breezy east-southeasterly winds continue over the next few hours at all sites before gradually diminishing overnight down to light and/or variable. MVFR ceilings are anticipated at KMFE, and possibly at KHRL as well, perhaps by around 04-06 Z, followed by intervals of VFR and MVFR later tonight into tomorrow morning. VFR skies are likely to persist at KBRO before scattered to broken VFR clouds and breezy east-southeasterly wind return to all terminals by tomorrow afternoon. Shallow fog is possible in the morning, but have left out of the TAFs for the time being.

MARINE

Issued at 110 PM CDT Sat May 30 2026

Awaiting the updated wave forecasts from our model which runs close to 130 PM CT, but regardless of forecast values this run, expect the trend on waves/wave period forecast to continue to rise over the next few days. Expected forecast today should push 4, perhaps 5 foot waves into the 20-60 nm leg but end result could see 6 and perhaps even 7 feet values by the time we get to Wednesday into Thursday.

Through Monday Night: Light to moderate winds and general slight seas will continue through this period under the weak pressure gradient, though expect moisture plume to produce isolated to scattered showers and a few thunderstorms late Monday and Monday night.

Tuesday through Thursday Night: Expect to swell period to increase with the strengthening pressure gradient and east-west fetch across the northern half of the Gulf, and would not surprise to see 8 or even 9 second swell for a time especially Thursday and Thursday night, with at least a 10-30% chance of 6 foot combined seas. Should this occur, Small Craft Exercise Caution will be needed for all or part of the Lower Texas Gulf waters between Wednesday (late) through Thursday night. Periodic rains especially the farther offshore one goes will add to the increase difficulty.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 77 92 79 92 / 0 0 10 10 HARLINGEN 73 92 76 92 / 0 0 10 20 MCALLEN 76 95 78 95 / 0 0 0 20 RIO GRANDE CITY 75 96 77 95 / 0 0 0 10 SOUTH PADRE ISLAND 80 85 81 85 / 0 0 10 10 BAYVIEW/PORT ISABEL 77 89 79 89 / 0 0 10 10

BRO WATCHES/WARNINGS/ADVISORIES

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