textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 1209 AM CDT Sat Apr 4 2026

Key Messages:

* Heavy rainfall and slow moving thunderstorms could result in instances of flooding and flash flooding over parts of the area Saturday night through Sunday night.

* Preliminary rainfall amounts by Monday morning will range between 1-2 inches with locally higher amounts; additional rainfall amounts are possible Monday and Tuesday.

* Adverse to hazardous marine conditions are expected into next week.

DISCUSSION

Issued at 1050 PM CDT Fri Apr 3 2026

A much welcomed pattern change is here for the holiday weekend, with a few light showers and isolated thunderstorms pushing across the border into Zapata County and potentially the upper valley early tonight.

There will be one more day of above normal temperatures before a cold front arrives Saturday night into early Sunday, offering up a 10-20 degree temperature drop from Saturday afternoon to late Sunday afternoon. Lows in the 50s are expected Monday and Tuesday mornings, with highs in the upper 60s to near 70 Monday and into the 70s on Tuesday, before drier and warmer conditions return.

Most importantly, aside from the break in the heat, confidence in beneficial rainfall continues, with deep column moisture accompanying the frontal boundary, a coastal trough setting up in its wake, and a surface low meandering near the lower Texas coast. Rainfall totals have trended slightly lower the past two model runs, but still sit in the vicinity of around 1 to 1.5 inches are expected across Deep South Texas with locally higher amounts near 2 inches or more where any rainfall persists. Higher totals have shifted a bit south of the border, closer to the surface low and higher terrain, still favoring portions of the brush country and upper valley in Zapata and Starr counties. A few strong to isolated severe thunderstorms are possible Saturday evening into Saturday night, especially across Zapata, Jim Hogg, and Starr counties, with off and on periods of showers and thunderstorms then expected across all of Deep South Texas through Sunday and Monday, kicking up along roaming outflow boundaries. Rainfall chances gradually taper off from west to east Tuesday into Wednesday.

There remains a Marginal (Level 1 of 4) Risk of Excessive Rainfall from Saturday into Monday morning. PWAT values near 1.7 to 2.0 inches arrive through the day Sunday, well above the 90th percentile for early April. Any shower or thunderstorm in this atmosphere will be a very efficient rainmaker. Given the lack of rainfall through the year for most locations, there will be an elevated concern for runoff and flash flooding where any heavy rainfall persists, especially in areas like southern Zapata and Starr counties.

AVIATION

(06Z TAFS) Issued at 1209 AM CDT Sat Apr 4 2026

Mostly MVFR conditions to persist through the overnight into the early morning hours. Southeasterly winds should stay light for the remainder of the overnight hours and early morning hours as well. The southeasterly winds should become more gustier with some gusts around 20 knots possible. During the late morning ceilings should improve to VFR status, but there could still be a few low-level clouds lingering over the region.

MARINE

Issued at 1050 PM CDT Fri Apr 3 2026

Southeasterly winds persist into Saturday night with Small Craft Caution conditions. A cold front late Saturday into Sunday brings northerly winds and potential SCA conditions across the Gulf, as well as showers and thunderstorms, including some heavy to strong showers and thunderstorms Saturday night through Monday. Southeasterly winds and drier weather gradually return early to mid next week.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 88 71 78 61 / 10 80 90 80 HARLINGEN 90 66 78 57 / 10 80 90 80 MCALLEN 94 69 77 60 / 30 80 90 80 RIO GRANDE CITY 93 63 71 56 / 50 90 90 80 SOUTH PADRE ISLAND 80 72 75 67 / 10 70 90 80 BAYVIEW/PORT ISABEL 87 69 78 61 / 10 70 90 80

BRO WATCHES/WARNINGS/ADVISORIES

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