textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 1240 PM CDT Sun Apr 12 2026

Key Messages:

* Showers and thunderstorms are possible this afternoon/evening with a conditional risk of those storms becoming strong to severe; confidence is low to medium (20-40%).

* Dry, warm, and at times breezy conditions are expected to return Monday and persist through next Saturday.

* A cool frontal boundary will bring another chance for showers and thunderstorms to the region next Sunday.

* Adverse (Small Craft Exercise Caution) marine conditions are expected to prevail through next week.

DISCUSSION

Issued at 1240 PM CDT Sun Apr 12 2026

The main weather concern will continue to focus on the chances for showers and thunderstorms and the conditional risk for those storms becoming strong to severe later this afternoon/evening.

Latest GOES-19 visible satellite imagery and radar scans revealed a BKN-OVC deck of stratus to stratocumulus clouds overhead with some sprinkles/rain showers around as the region sits under an at times active southwest flow aloft regime and on the leeward side of a potent upper low over the western U.S.

All of the rain shower activity from this morning is ahead of additional shortwave energies that will be tracking overhead later this afternoon into this evening, which could lead in a renewed threat for showers and thunderstorms. CAPE values are stronger than yesterday and mid-level lapse rates are solid enough to support thunderstorm development. However, the abundance of cloud cover and weak forcing overall could keep the severity of thunderstorms limited, which is why there is a conditional risk for strong to severe thunderstorms later on. The Storm Prediction Center (SPC) has practically the entire area under a Marginal or Isolated Risk (Level 1 of 5) for severe thunderstorms later this afternoon/evening. The best timeframe for these thunderstorms to develop or move into the region looks to be between the hours of 6pm CDT this evening to 3am CDT Monday.

Heavy rainfall and localized flooding is possible this evening/tonight due to the combination of high atmospheric moisture content and the potential for slow moving storms. Precipitable water (PWAT) values are between 1.5-2 inches, some +1 to +3 STDEVs above normal. We will continue to monitor thunderstorm, severe weather, and heavy rainfall/flooding trends through this evening. Otherwise, expect for warm and mainly dry conditions to continue. High temperatures today are expected to top out in the mid 80s near the coast to near 90F degrees west.

Rain-free, warmer than normal, and at times breezy conditions will prevail Monday through next Saturday. High temperatures are progged to range between the upper 80s to mid 90s. Overnight low temps are expected to range between the upper 60s/low 70s over the Northern Ranchlands to the low to mid 70s along the Rio Grande Valley.

An approaching cold frontal boundary from the northwest could result in another opportunity for showers and thunderstorms next Sunday. High temperatures will also be a bit lower with values in the low to mid 80s most places; upper 70s northwest.

AVIATION

(18Z TAFS) Issued at 1240 PM CDT Sun Apr 12 2026

Through 18z Monday....Latest GOES-19 visible satellite imagery and sfc observations depicted a BKN-OVC deck of MVFR clouds overhead with cloud bases ranging between 1,500-3,000 feet AGL and unrestricted visibilities. Doppler radar indicated a few rain showers mainly along the IH-69C and IH-69E corridors this afternoon. Have VCSH headlines over MFE and HRL this afternoon.

MVFR cigs are expected to persist through the entire 18z TAF period. Showers and thunderstorms are also possible this evening into tonight in response to multiple shortwaves riding overhead. Any thunderstorms that develop or moves over a terminal will have the capabilities of briefly reducing cigs/visibilities to IFR-LIFR levels.

Winds will continue out of the south-southeast 10-20 kts with gusts as high as 25-30 kts through the 18z period.

MARINE

Issued at 1240 PM CDT Sun Apr 12 2026

Adverse (Small Craft Exercise Caution) marine conditons will prevail through next week thanks to an enhanced pressure gradient resulting in breezy winds out of the south and building wave heights. Small Craft Exercise Caution headlines will likely be needed each afternoon through next week.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 73 85 73 86 / 20 0 0 0 HARLINGEN 70 88 70 89 / 20 0 0 0 MCALLEN 74 91 75 91 / 30 0 0 0 RIO GRANDE CITY 72 90 72 93 / 30 0 0 0 SOUTH PADRE ISLAND 73 79 73 79 / 20 0 0 0 BAYVIEW/PORT ISABEL 71 85 71 85 / 20 0 0 0

BRO WATCHES/WARNINGS/ADVISORIES

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