textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 624 AM CDT Wed Jun 3 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

(12Z TAFS) Issued at 624 AM CDT Wed Jun 3 2026

VFR conditions are forecast to continue this morning. Isolated to scattered convection will be possible along the sea breeze this afternoon, and brief MVFR to IFR conditions are possible with any showers or thunderstorms that develop. Otherwise, VFR conditions are forecast to prevail, with winds becoming easterly at around 10 knots this afternoon.

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 90 78 90 79 / 50 10 20 0 HARLINGEN 90 74 89 75 / 50 20 20 0 MCALLEN 92 76 92 77 / 50 10 20 10 RIO GRANDE CITY 94 74 92 75 / 30 30 20 30 SOUTH PADRE ISLAND 85 80 85 81 / 30 10 10 0 BAYVIEW/PORT ISABEL 88 77 88 78 / 30 10 10 0

BRO WATCHES/WARNINGS/ADVISORIES

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