textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 608 PM CDT Sun May 10 2026

Key Messages:

* Showers and thunderstorms are possible this afternoon, with a better chance late this evening through tonight.

* There is a Marginal (Level 1 of 5) Risk for severe thunderstorms through Monday morning, with the main hazards being damaging winds and hail late tonight.

* Mainly dry weather with warming temperatures will prevail through next week.

DISCUSSION

Issued at 1248 PM CDT Sun May 10 2026

The morning sounding at BRO showed PWAT at 1.86 inches, above the 90th percentile for early to mid May, meaning there remains an abundance of moisture across Deep South Texas. The persistent MVFR cloud deck this morning helps confirm this as well. There is plenty of CAPE and shear for thunderstorm development and with a convective temp of 91, and numerous boundaries roaming around, have bumped POPs up across typical sea breeze locations this afternoon, working generally inland through the afternoon. CAMs are again widely varied on convection development timing and location, but all develop something, lending confidence in at least a handful of showers and thunderstorms mid to late afternoon into early evening, especially if the sun can peek out consistently this afternoon.

A potent frontal system up north is working south this afternoon into tonight, bringing another round of showers and thunderstorms to Deep South Texas this evening into late tonight. Any Sierra Madre convection could pair with this front or bring a couple of storms into Zapata County this evening out ahead of it. SPC has all of Deep South Texas under a Marginal (level 1 of 5) Risk of severe weather through tonight, with the best chance occurring with the frontal boundary late tonight, but highly dependent on what happens upstream. WPC is also highlighting Zapata, Jim Hogg, Starr, and western Hidalgo counties with a Marginal (level 1 of 4) Risk of Excessive Rainfall through tonight, meaning any persistent showers or thunderstorms could pose a flooding rain threat.

Overall, confidence is a little lower on severe weather this afternoon, but expect a couple of thunderstorms mid to late this afternoon into this evening, with better coverage along the front tonight. The main hazards would be hail and damaging winds, if any strong to severe thunderstorms develop, transitioning to more of a wind threat late tonight into early Monday morning across the lower Valley, if anything is still hanging tough by then.

The forecast beyond tonight dries out and gradually warms up into next weekend. There remains a moderate risk of life-threatening rip currents along the lower Texas coast due to long period swell into early this week and again next weekend.

AVIATION

(00Z TAFS) Issued at 608 PM CDT Sun May 10 2026

Through 00z Tuesday....The weather concern for the terminals over the next 12 hours or so will be the chance for showers and thunderstorms ahead of a cold front this evening and again along the cold front overnight tonight into Monday morning.

Latest GOES-19 visible satellite imagery, radar, and sfc obs indicated VFR conditions at all of the TAF sites under a SCT-BKN deck of cumulus clouds. Towering cumulonimbus clouds associated with a strong thunderstorm was located so the southwest of MFE and cold impact the site within the next couple of hours and it continues to move towards the northeast. Additional showers and thunderstorms could develop this evening and shift eastward towards HRL and BRO. We'll continue to monitor trends. For now, have VCTS and TEMPO groups for MFE to account for the developing thunderstorm just to the southwest. Additionally, I have Prob30 groups for all the TAF sites for tonight.

Any showers or storms this evening and/or through the overnight hours into Monday morning will be capable of briefly reducing cigs/vsbys down to IFR/LIFR levels.

Southeast winds 10-15 kts this evening will trend towards light and variable tonight. Behind to cold front winds will shift out of the northeast with speeds between 5-15 kts on Monday.

MARINE

Issued at 1248 PM CDT Sun May 10 2026

Southeasterly winds give way to the next frontal boundary late tonight into Tuesday. This briefly elevates seas and winds, before more favorable marine conditions return mid week into next weekend. There remains a chance of showers and strong to severe thunderstorms into Monday, especially along the front tonight, with drier and more favorable conditions the remainder of the week.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 77 87 74 87 / 40 30 0 0 HARLINGEN 74 86 70 86 / 50 30 0 0 MCALLEN 76 87 73 88 / 50 40 0 0 RIO GRANDE CITY 74 86 72 87 / 60 40 20 0 SOUTH PADRE ISLAND 78 82 77 81 / 40 20 0 0 BAYVIEW/PORT ISABEL 76 85 74 85 / 50 30 0 0

BRO WATCHES/WARNINGS/ADVISORIES

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