textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 402 PM CDT Tue May 26 2026

Key Messages:

* The Storm Prediction Center (SPC) has extended a Slight Risk (level 2 of 5) of scattered severe thunderstorms further east over the Northern Ranchlands and Middle RGV, featuring a primary risk of scattered damaging (58+ mph) winds and large to very large (1 to 2+ inch) hail.

* The coastal counties and eastern half of the Northern Ranchlands remain within a Marginal Risk (level 1 of 5) of isolated severe thunderstorms, bringing the possibility of isolated damaging winds and large hail.

* Low to moderate (20 to 50%) chances for showers and thunderstorms continue through tomorrow evening. Then conditions should begin to dry out.

* Warm and dry conditions should persist Thursday through the weekend, with the potential for Moderate (level 2 of 4) to Major (level 3 of 4) Heat Risk.

* There is a moderate risk of rip currents tonight and tomorrow.

UPDATE

Issued at 402 PM CDT Tue May 26 2026

This is an updated Area Forecast Discussion to notify that SPC updated their Day 1 Convective Outlook, which continues through the rest of today and tonight, and expanded the Slight Risk (level 2 of 5) for scattered severe thunderstorms eastward, to include more of the Northern Ranchlands and Upper/Middle RGV. Specifically, the Slight Risk's eastern edge now reaches as far east as the western half of Brooks County and the far western portions of Hidalgo County. Convective activity is likely to occur later tonight, perhaps around 10 or 11 PM, at the earliest, beginning over the far western areas, along/near the Rio Grande, of the Upper RGV and Rio Grande Plains. The primary risks include a 15-29% probability (within 25 miles of any point) of scattered damaging (58+ mph) wind for the entire Slight Risk zone as well as scattered large (1-2+ inch) hail as far east as the western half of Jim Hogg and Starr counties. Locations east of the Slight Risk's eastern fringe remain under a Marginal Risk (level 1 of 5) for isolated damaging winds all the way to the coast and isolated large (1+ inch) hail as far east as the western portions of the coastal counties.

DISCUSSION

Issued at 101 PM CDT Tue May 26 2026

A deeply moist and unsettled atmospheric pattern continues through mid-week, due to a combination of ample Gulf surface moisture and Pacific moisture aloft, along with continued embedded mid-level and upper-level shortwave activity. This will provide enough instability to support low to medium chances (20 to 50%) shower and thunderstorm formation through tomorrow afternoon.

The Storm Prediction Center currently has a small portion of the Western Ranchlands in a slight risk for severe thunderstorms this evening, and a marginal risk for the rest of Deep South Texas. This threat is highly conditional on the atmosphere's ability to recover from ongoing morning shower and rain activity. However, CAM guidance seems to be in agreement that isolated to scattered thunderstorms will develop off the Mexican Sierra Madres late afternoon/early evening, and some of this convection could reach Deep South Texas and the Rio Grande Valley. If these storms happen to make it to our area, the biggest threat will be gusty winds and heavy rain (with the potential for isolated flash flooding), but some moderate hail is possible as well. Western portions of the CWA are under a marginal risk (level 1 of 4) for excessive rainfall, associated with any heavy rainfall these storms may bring. Flash flooding may occur near arroyos, low lying areas, and urban/poor drainage areas.

Tomorrow the chances for any severe weather decrease, but due to the overall unstable atmospheric profile, scattered showers and thunderstorms are still possible, particularly in the mid-morning and early afternoon. Some of these could be strong. The potential for heavy rain and isolated flash flooding continues tomorrow, mostly for areas east of I-69C.

By tomorrow night, conditions should begin to dry out, as the shortwave activity subsides and the atmosphere begins to stabilize. High pressure is expected to form southwest of the region, which should keep conditions warm and dry for the latter part of the week into the weekend. High temperatures are expected to warm from the lower 90s to the upper 90s by the end of the weekend. Heat Risk will also become more of a concern as more areas will experience Moderate (level 2 of 4) and even Major (level 3 of 4) Heat Risk as the week progresses through the end of the weekend.

Some guidance is hinting that a weak cold front could reach the area next week as the next Pacific trough moves in from the west. It is not expected to make much impact on temperature, but could bring northerly winds to the region and bring some relief to the humidity. This will continue to be monitored.

There is a moderate risk of life-threatening rip currents at area beaches tonight and tomorrow.

AVIATION

(18Z TAFS) Issued at 101 PM CDT Tue May 26 2026

VFR conditions are expected at all airport, with overcast ceilings that may become scattered or broken at times. Southeasterly winds may become gusty this afternoon. This evening, MVFR ceilings are expected to develop between 02-07z and there may be showers in the morning, particularly at BRO and HRL.

MARINE

Issued at 101 PM CDT Tue May 26 2026

SCEC conditions are possible tomorrow as a shortwave moves over the area. Then conditions are expected to improve and stay favorable through the weekend. Wave heights between 2-4 feet are expected with light to moderate southeasterly winds.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 80 90 78 92 / 10 30 10 20 HARLINGEN 77 91 75 92 / 20 40 10 20 MCALLEN 78 93 77 94 / 30 30 20 10 RIO GRANDE CITY 75 94 75 94 / 40 20 10 10 SOUTH PADRE ISLAND 81 85 80 85 / 10 30 20 10 BAYVIEW/PORT ISABEL 79 89 78 90 / 20 30 10 10

BRO WATCHES/WARNINGS/ADVISORIES

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