textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 1235 AM CDT Thu Jun 4 2026

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

* There still remains low-medium (20-50%) chances for showers and thunderstorms through Saturday. Friday into Friday evening, there's a medium (30-60%) 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.

* A Marginal Risk (Level 1 of 4) for excessive rainfall is in place for all of Deep South Texas on Friday.

* Seasonable temperatures on persistent east-southeast winds will prevail through next week; heat risk however 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 the middle parts of next week.

DISCUSSION

Issued at 1027 PM CDT Wed Jun 3 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 early next week. Early indications suggest that next week will be drier than this week overall as rain probabilities and coverage will be lower next week compared to this week.

Model trends have remained consistent with previous model runs over the past 24 hours in depicting continued weakening of the sfc and upper level high pressure systems through the remainder of this week. 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 continue to support support day-to-day to near day-to-day chances for showers and thunderstorms through this upcoming weekend. Coverage generally will be isolated to scattered each day. The best chances and coverage for showers and thunderstorms will be Friday-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 have medium (30-60%) chances for showers and thunderstorms (highest favoring areas 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 generally 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 northwestern Zapata County 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 in the days ahead.

Day-to-day or near day-to-day rain chances could continue through the early parts of next week. However, confidence and coverage remains low at this time. That said, an isolated shower or thunderstorm is possible Sunday through Wednesday of next week. Rain probabilities at this point are maxed out at 20% each of those days.

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 than normal high temperatures and slightly higher than normal low temperatures. High temperatures are expected to run between the upper 80s to mid 90s through the upcoming weekend. Meanwhile, overnight lows are expected to be mainly in the 70s (80s across SE Cameron County) through next week.

Heat Risk could begin picking up late next weekend (Sunday) through the middle parts of next week, especially if drier weather conditions occur. 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 Thursday. Heat indices are progged to range between 100-110F degrees late weekend through mid next week.

AVIATION

(06Z TAFS) Issued at 1235 AM CDT Thu Jun 4 2026

VFR conditions light and variable to calm winds are forecast to continue overnight. Isolated to scattered convection is possible along the sea breeze Thursday afternoon, these showers and thunderstorms could briefly drop ceilings and visibilities to MVFR or IFR levels. Otherwise, VFR ceilings light to moderate easterly winds are forecast through the afternoon.

MARINE

Issued at 1027 PM CDT Wed Jun 3 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 morning. Friday afternoon though next Tuesday, adverse marine conditions such as Small Craft Exercise Caution (SCEC) conditions are expected to develop.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 90 78 90 79 / 30 10 20 20 HARLINGEN 89 75 90 76 / 30 10 30 20 MCALLEN 92 77 91 77 / 30 10 50 40 RIO GRANDE CITY 93 75 90 74 / 20 30 50 60 SOUTH PADRE ISLAND 85 81 86 82 / 20 10 10 20 BAYVIEW/PORT ISABEL 88 78 88 79 / 30 10 20 20

BRO WATCHES/WARNINGS/ADVISORIES

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