textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 619 AM CDT Mon Jun 15 2026

- A Flood Watch is in effect from Monday afternoon through Wednesday morning. Numerous Flash Floods are likely Monday into Tuesday.

- There is a Marginal (level 1 of 4) Risk of Excessive Rainfall across Deep South Texas overnight. There is a Slight (level 2 of 4) to Moderate (level 3 of 4) Risk of Excessive Rainfall across the area Monday and Monday night. A Slight (level 2 of 4) Risk of Excessive Rainfall across all of Deep South Texas Tuesday and Tuesday night. A Marginal to Slight Risk of Excessive Rainfall continues across much of the region Wednesday into Wednesday night with a Marginal Risk lingering along the coast on Thursday. - A Moderate to Major (levels 2-3 of 4) Heat Risk is forecast Thursday into Saturday. Heat Advisories may be needed Thursday and Friday.

- The National Hurricane Center continues a low chance (30%) of tropical development over the northwestern Gulf over the next 7 days.

DISCUSSION

Issued at 1043 PM CDT Sun Jun 14 2026

The combination of an enhanced seabreeze, a low of low pressure over northeastern Mexico/Deep South Texas and the interaction of a weak front boundary will lead to unsettled weather through at least midweek. Deep tropical moisture will continue to surge into Deep South Texas tonight into Tuesday. This evening's 0Z Brownsville sounding indicated a PWAT value of 2.38 inches. Rain chances are expected to increase after midnight and there is a moderate to high (50-70%) chance of rain overnight, mainly across the Low to middle Rio Grande Valley and along the coast. The latest HRRR suggests that some activity may develop and move into Cameron County around 3 AM. There is a moderate to high (50-80%) chance of rain showers and isolated thunderstorms on Monday, especially in the afternoon and early evening. The forecast rainfall amounts between 1.5 to 3 inches, locally higher. PWATS surge between 2.5 to 2.75 inches across the Rio Grande Plains Monday evening. Rain chances increase to high (75-90%) Monday night. Numerous flash floods are likely across Deep South Texas with scattered flash flooding possible near the coast.

High (80-90%) rain chances continue Tuesday with scattered flash flooding possible. Rain chances (30-60%) Tuesday night decreasing from west to east. Forecast rainfall amounts between 1.5 to 3 inches, locally higher. Rain chances linger Wednesday into Wednesday night as timing remains uncertain between the model guidance. There is a low to moderate (20-50%) chance of rain, especially near the coast on Wednesday with a low chance Wednesday night.

The forecast rainfall totals across the area from Monday into Wednesday are 3 to 6 inches, with locally higher amounts of 8 inches or higher where showers or thunderstorms persist.

The trough of low pressure located over northeastern Mexico could re- emerge over the Gulf late Tuesday into Wednesday. The National Hurricane Center has a 30% chance for tropical development through day 7. Any development at that point would likely have minimal impact on Deep South Texas. However, some increased swell along the coast is possible, which could result in minor coastal flooding and increased rip current risk.

The increased cloud cover and rain chances will lead to slightly lower daytime temperatures through midweek. Drier weather returns on Thursday as high humidity continues. There is a Moderate to Major (levels 2-3 of 4) Heat Risk Thursday into Saturday. Heat Advisories may be needed Thursday and Friday.

AVIATION

(12Z TAFS) Issued at 619 AM CDT Mon Jun 15 2026

The latest issuance of TAFs reflect current radar trends as well as shifts in the HRRR model guidance. Overall, VFR will remain for a majority of the period. Prevailing TSRA will occur tonight as deep tropical moisture interacts with low pressure in the middle layers of the atmosphere.

MARINE

Issued at 1043 PM CDT Sun Jun 14 2026

Generally favorable marine conditions are forecast to continue through Tuesday. Showers and thunderstorms will increase along the Lower Texas Coast and the Gulf waters tonight through mid to late week. Adverse to hazardous conditions could return Wednesday and Thursday, and Small Craft Advisories or Small Craft Should Exercise Caution headlines may be needed.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 90 79 85 77 / 50 70 80 60 HARLINGEN 89 76 84 74 / 60 80 90 60 MCALLEN 90 77 84 77 / 80 90 90 50 RIO GRANDE CITY 90 75 84 74 / 80 90 90 40 SOUTH PADRE ISLAND 87 81 85 80 / 40 60 70 60 BAYVIEW/PORT ISABEL 89 78 85 77 / 50 70 80 60

BRO WATCHES/WARNINGS/ADVISORIES

TX...Flood Watch from 1 PM CDT this afternoon through Wednesday morning for TXZ248>255-351-353>355-451-454-455.

GM...None.