textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 627 AM CDT Sun Aug 31 2025

-Heat continues to be a concern especially through Monday with a Moderate (level 2 out of 4) to Major (level 3 out of 4) Heat Risk.

-Rain chances increase for Monday and Tuesday.

-The Weather Prediction Center continues to highlight northern portions of Zapata, Jim Hogg, Brooks, and Kenedy counties in a Marginal Risk (level 1 of 4) of excessive rainfall on Monday.

DISCUSSION

Issued at 1022 PM CDT Sat Aug 30 2025

Heat continues to be the main focus for the start of the forecast period. Mid-level ridging and moisture advection with south- southeasterly winds will continue to bring hot temperatures rising into the upper 90s to 100s and heat indices between 105 to 110 degrees across Deep South Texas and the Rio Grande Valley. This will maintain a Moderate (level 2 out of 4) to Major (level 3 out of 4) Heat risk for the region through Monday. While heat indices will remain below Heat Advisory criteria, Special Weather Statements will be needed. Tuesday temperatures cool slightly, but will remain near to just above seasonal norms for the remainder of forecast period.

As we head into Monday a cold front begins to push southward, stalling just north of the CWA. This will bring increasing chances of showers and thunderstorms on Monday (40-60%) and Tuesday (50-70%). WPC has a small portion of the Northern Ranchlands in a marginal risk (level 1 out of 4) on Monday. There is some uncertainty in the rainfall forecast, especially across the northern Ranchlands. If the front stalls farther north, rain chances will decrease. With that said, latest forecast guidance has increased rain chances across Deep South Texas slightly on Monday and more noticeably on Tuesday. Rain chances taper off Tuesday night and will generally remain around 15% or less for Wednesday and Thursday. There will be a slight uptick in precip chances headed into next weekend as we look at the potential of another approaching and passing cold front at the end of the forecast period.

AVIATION

(12Z TAFS) Issued at 627 AM CDT Sun Aug 31 2025

VFR conditions are expected to continue through the period. Light to moderate southeasterly winds are expected to continue through the day with mostly clear skies. Cloud cover is expected to increase early Monday morning ahead of a cold front that will be approaching the region near the end of the forecast period. However, skies will likely remain scattered through the end of the TAF period.

MARINE

Issued at 1216 PM CDT Sat Aug 30 2025

Generally favorable conditions with mostly light to moderate southerly to southeasterly winds and seas of 1 to 2 ft. A frontal boundary will stall north of the CWA increasing rain and thunderstorms chances Monday and Tuesday (50-70%) before pushing through late tuesday. This activity could lead to locally elevated winds and seas.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 96 79 95 79 / 10 10 40 40 HARLINGEN 98 75 97 75 / 10 0 50 50 MCALLEN 102 79 101 79 / 0 10 40 50 RIO GRANDE CITY 103 77 101 77 / 0 0 30 60 SOUTH PADRE ISLAND 90 82 89 80 / 0 10 30 50 BAYVIEW/PORT ISABEL 94 78 93 77 / 0 10 30 50

BRO WATCHES/WARNINGS/ADVISORIES

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