textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 526 PM CDT Wed Jun 3 2026

* Daily low to medium (20-50%) chances of rain continue along seabreeze boundaries through Saturday, generally peaking in coverage and activity along/east of US-281 in the early to late afternoon hours. Heavy downpours, frequent lightning and stronger wind gusts are possible within the deepest of convection.

* WPC highlights a Marginal Risk (Level 1 of 4) of flash flooding from excessive and heavy rainfall for northwestern Zapata County Thursday night, expanding to all of deep south Texas on Friday, when chances of rain increase to a medium to likely (40-70%) chance, higher further west.

* Temperatures in the upper 80s/low 90s, heat indices around 95-103 F and mostly minor heat risks (level 1 of 4) elevate to widespread moderate heat risks (level 2 of 4) on Sunday and next Monday as rain chances decrease and sunshine return, causing heat indices to spike to 100-105+ F.

* A low risk of rip currents continues through tomorrow afternoon.

* Adverse marine conditions are possible this weekend into the beginning of next week.

DISCUSSION

Issued at 1249 PM CDT Wed Jun 3 2026

Scattered to numerous slow-moving showers and isolated thunderstorms have been developing along the westward-moving seabreeze boundary throughout this morning and early afternoon along/east of I-69 E, most concentrated over Kenedy County, though have also been initiating further west across the Northern Ranchlands, where convergence is enhancing ahead of an arriving weak surge of high pressure. As the seabreeze works further inland and additional lift pushes southwestward into the afternoon and early evening hours, chances of rain increase to as much as a low to medium (30-60%) chance, with the highest PoPs remaining along/east of US-281. Some CAMs also indicate the possibility of stronger thunderstorms capable of producing frequent lightning, heavy rain and stronger winds (40+ mph), which could prompt SPSs later this afternoon. Most areas can expect generally around a trace to 0.20 of an inch of rain, though a few areas along/east US-281 could receive up to 0.50 to an inch of rain, or more, within the deepest of convection, especially if storm movement remains slow. Like yesterday, Flood Advisories could be issued later as well.

A high pressure aloft over central Mexico shifts northeastward to the Gulf during the daytime on Thursday, cutting PoPs down to a low (15-30%) chance along the seabreeze.

Although CAMs are still a bit incohesive at this time, mid/upper level troughing takes over again Thursday night, with robust vorticity advection likely developing strong thunderstorms and heavy rain over the Sierra Madre. Storms should weaken as they approach Texas, yet, if convection can sustain to the border, heavy rain is possible late Thursday night and early Friday morning across the Rio Grande Plains and Upper RGV, where there is a low to medium (20-50%) chance of rain. Following, showers and thunderstorms may develop Friday afternoon further east, bringing the potential for heavy rain as PoPs increase region-wide to a medium to likely (40-70%) chance, highest furthest west.

WPC maintains a Marginal Risk (level 1 of 4) of flash flooding from excessive and heavy rainfall for extreme northwestern Zapata County Thursday night and a Marginal Risk across all of deep south Texas on Friday. Thursday night through Friday night, most areas along/west of US-281 can expect generally around 0.20-0.30 of an inch of rain, though northwestern Zapata County could see closer to half an inch or more. As PWAT values of 2.0-2.4+ in. persists across the entire region, a few areas could receive an inch, or several inches, from heavy rain within stronger slow-moving thunderstorms and where convection trains. Currently, the NBM yields a 20-45% chance of rainfall totals exceeding 1 inch Thursday into Friday, highest over the Rio Grande Plains.

A low to medium (20-40%) chance of rain along the seabreeze boundary continues on Saturday before PoPs decrease by Sunday as high pressure aloft regains control.

Through Saturday, a mostly minor heat risk continues for most of the region aside from a medium risk across portions of the coastal counties and the RGV. Highs in the upper 80s/lower 90s with heat indices around 95-103 F increase to the low/mid 90s and widespread apparent temperatures of 100-105+ F later this weekend, resulting in region-wide moderate heat risks Sunday into Monday. Daily low chances of rain return by the middle of next week with minor to moderate heat risks.

A low risk of rip currents continues through tomorrow afternoon.

AVIATION

(00Z TAFS) Issued at 526 PM CDT Wed Jun 3 2026

Through 00z Friday....VFR conditions, by and large, will prevail through the 00z TAF cycle. There could be a few MVFR clouds around from time to time.

To a lesser extent than the past few days, another round of diurnal showers and thunderstorms along the sea breeze is possible on Thursday. Have Prob30 groups to acknowledge the potential once again for showers and thunderstorms on Thursday with the best timing being between 18z-23z/Thursday. Any showers or thunderstorms that move over a terminal will have the capabilities of reducing cigs/vsbys. Brief heavy downpours, frequent lightning, and maybe some gusty winds and/or small hail can be expected with any storms.

East-southeast winds 5-10 kts this evening will trend towards light and variable to calm tonight. East-southeast winds 5-10 kts are expected to develop once again on Thursday.

MARINE

Issued at 1249 PM CDT Wed Jun 3 2026

Gentle to moderate easterly to southeasterly winds and slight to moderate (2-4 feet) seas increase and build to moderate to fresh with moderate (4-6 feet) seas over the weekend. Small Craft Exercise Caution headlines are possible into early next week before winds ease to gentle to moderate. Daily low (15-30%) chances of rain continue into this weekend with lower chances later this weekend into next week.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 78 90 79 90 / 10 30 10 30 HARLINGEN 74 89 75 90 / 10 30 10 50 MCALLEN 77 92 77 91 / 10 20 10 60 RIO GRANDE CITY 74 92 75 90 / 20 20 30 60 SOUTH PADRE ISLAND 81 85 81 86 / 10 20 10 10 BAYVIEW/PORT ISABEL 77 88 78 88 / 10 20 10 20

BRO WATCHES/WARNINGS/ADVISORIES

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