textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 1024 PM CDT Tue Jun 2 2026

* Day-to-day or near day-to-day diurnal shower and thunderstorm chances are expected through next weekend along a sea breeze; best timing will be between 11 AM to 5 PM CDT.

* Generally, there remains low-medium (20-50%) chances for showers and thunderstorms through Saturday. Friday into Friday evening, there's a medium-high (40-70%) chance for showers and thunderstorms.

* Brief periods of heavy rainfall, frequent lightning, small hail, and gusty winds will be the main threats in the stronger storms.

* Seasonable temperatures on persistent east-southeast winds will prevail through the workweek; heat risk could begin increasing late weekend through early next week.

* Widespread Moderate (Level 2 of 5) Heat Risk is expected to develop beginning Sunday and persisting through at least the early parts of next week.

DISCUSSION

Issued at 1024 PM CDT Tue Jun 2 2026

Daily to near daily chances for showers and thunderstorms along a sea breeze on persistent east-southeast winds with near seasonable temperatures will continue to be the main weather storyline through next weekend.

The latest suite of computer models have remained consistent with previous model runs over the past 24 hours in depicting sfc and upper level high pressure weakening in time as this week wears on. High atmospheric moisture content with PWAT values ranging between 1.8-2.5", some 2-3 STDEVs above normal, elevated instability values, and increased sfc convergence from a sea breeze will support near day-to-day chances for showers and thunderstorms through next weekend. Coverage will be isolated to scattered each day through next weekend. The best chances and coverage for showers and thunderstorms will be Wednesday through Friday evening.

In general, through Saturday there remains a low-medium (20-50%) chance for showers and thunderstorms. Friday will present the greatest rain and thunderstorm chances due to a combination of sea breeze interaction and synoptic influences. That's where we continue to have medium-high (40-70%) chances for showers and thunderstorms (highest west of IH-69C/US-281). Brief periods of heavy rain, frequent lightning, and maybe some small hail and gusty winds will be the main threat with the stronger storms. Since the sea breeze convection will be diurnally driven, the best chances for showers and thunderstorms will be between the hours of 11 AM to 5 PM CDT each day.

Given the high PWAT values, locally heavy rainfall could lead to localized nuisance ponding or flooding, particularly in your typical low-lying, urban, poor drainage areas. The Weather Prediction Center (WPC) has placed the northwestern sections of our CWA (i.e. Zapata, parts of Jim Hogg and Starr counties) under a Marginal (Level 1 of 4) Risk for excessive rainfall on Thursday and continues to have all of Deep South Texas under a Marginal (Level 1 of 4) Risk for excessive rainfall on Friday. We'll continue to monitor these trends and the week progresses.

The daily or near daily threat for showers and thunderstorms will help to keep the heat in check through next weekend. Overall, temperatures are expected to balance out near normal levels for the period with slightly lower high temperatures and slightly higher than normal low temperatures. High temperatures are expected to run between the upper 80s to mid 90s through the forecast period. Meanwhile, overnight lows are expected to be mainly in the 70s (80s across SE Cameron County) through early next week.

Heat Risk could begin picking up late next weekend (Sunday) through the middle parts of next week, especially if drier weather conditions develop. Currently, we have Moderate (Level 2 of 5) Heat Risk developing over much, if not all, of Deep South Texas on Sunday and persisting through next Wednesday. Heat indices are progged to range between 105-110F degrees late weekend into mid next week.

AVIATION

(00Z TAFS) Issued at 504 PM CDT Tue Jun 2 2026

Through 00z Thursday....By and large, VFR conditions will prevail through the 00z TAF cycle. There could be a few MVFR clouds around from time to time. The latest GOES-19 visible satellite imagery and radar this afternoon shows the latest round of sea breeze convection fizzling out as it shifts west of the IH-69E corridor into a less favorable environment. That said, through the remainder of this afternoon and evening, expect for improving flying conditions towards mainly VFR levels (maybe a few MVFR clouds).

Moving forward into Wednesday, another day of diurnal showers and thunderstorms are expected to continue along the sea breeze, specifically during the hours between 18z-23z. Have included Prob30 groups for the terminals to account for the potential for showers and thunderstorms between 18z-23z/Wed.

Any showers or thunderstorms that develop or pass over the terminals will have the capabilities of producing brief heavy downpours, frequent lightning, small hail, and gusty winds. These conditions could result in a brief downgrade of flight categories ranging from MVFR-LIFR.

East-southeast winds 5-12 kts this afternoon/evening will weaken and trend towards light and variable to calm tonight. On Wednesday, east- southeast winds will once again pick up with speeds between 5-12 kts.

MARINE

Issued at 1024 PM CDT Tue Jun 2 2026

Outside of the daily or near daily threat for showers and thunderstorms, favorable marine conditions with light to moderate winds and seas are expected to persist through Friday. Friday night though next Monday, adverse marine conditions such as Small Craft Exercise Caution (SCEC) conditions are expected to develop.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 78 90 77 90 / 10 30 10 10 HARLINGEN 75 90 74 90 / 10 30 10 10 MCALLEN 77 92 76 92 / 10 40 10 20 RIO GRANDE CITY 76 94 75 92 / 10 10 20 10 SOUTH PADRE ISLAND 81 85 80 85 / 20 20 10 0 BAYVIEW/PORT ISABEL 78 88 77 88 / 20 20 10 10

BRO WATCHES/WARNINGS/ADVISORIES

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