textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 1032 PM CDT Mon Jun 1 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.

* The best chances for showers and thunderstorms will be Wednesday through Friday. Generally, there are low-medium (20-50%) chances for showers and thunderstorms through next weekend. Friday, there is 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 into early next week.

* Widespread Moderate (Level 2 of 5) Heat Risk is expected to develop beginning Sunday and persisting through Tuesday of next week.

DISCUSSION

Issued at 1032 PM CDT Mon Jun 1 2026

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

The latest set of computer models have remained consistent with prior models over the past 24 hours in depicting sfc and upper level high pressure weakening in time as this week progresses. 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.

In general, through Saturday there is a low-medium (20-50%) chance for showers and thunderstorms. Friday will present the greatest rain and thunderstorm chances. That's where we currently have medium- high (40-70%) chances for showers and thunderstorms. 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 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 wears on.

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 early 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 Tuesday. Heat indices are progged to range between 105-110F degrees late weekend into early next week.

AVIATION

(00Z TAFS) Issued at 533 PM CDT Mon Jun 1 2026

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

East-southeast winds will continue through the evening with speeds between 5-10 kts. Tonight, winds will trend towards light and variable to calm. In Tuesday, east-southeast winds will pick up again with speeds between 5-10 kts.

MARINE

Issued at 1032 PM CDT Mon Jun 1 2026

Outside of the daily or near daily threat for showers and thunderstorms, favorable marine conditions will 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 79 91 78 90 / 0 30 10 30 HARLINGEN 75 91 74 89 / 10 30 10 40 MCALLEN 78 94 77 92 / 0 20 10 40 RIO GRANDE CITY 76 95 75 92 / 10 10 10 30 SOUTH PADRE ISLAND 81 85 80 85 / 0 10 20 20 BAYVIEW/PORT ISABEL 78 88 77 88 / 10 20 20 30

BRO WATCHES/WARNINGS/ADVISORIES

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