textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 1217 AM CDT Wed Apr 29 2026

Key Messages:

- High temperatures in the mid/upper 90s and afternoon "real- feel" temperatures/heat indices of 100-105 F result in mainly a Moderate (Level 2/4) Heat Risk on Wednesday and Thursday afternoons.

- High pressure aloft gradually eases beginning Thursday, leading to a Minor (Level 1/4) to Moderate Heat Risk on Friday.

- Cold front dives southward through the County Warning Area (CWA) Friday night, bringing a low to medium (30-40%) chance of rain, breezy to gusty northerly winds into Saturday and much cooler temperatures over the weekend.

- Dangerous rip currents and risks of minor coastal flooding are likely behind the front this weekend.

- Temperatures gradually warm to near normal by next Monday and Tuesday.

DISCUSSION

Issued at 1029 PM CDT Tue Apr 28 2026

Not much has changed for the upcoming 7 days across Deep South Texas with this latest forecast package. 591 dam mid/upper level high pressure persists over central Mexico throughout Wednesday before shifting eastward Thursday into this weekend in response to a digging mid/upper level shortwave trough moving east into western Texas by Friday. Meanwhile, another trough deepening just north of the Great Lakes helps to weaken and flatten the high pressure as well as slowly push a frontal boundary into central or southern Texas Wednesday night. While conditions are likely to remain dry, some CAMs and global deterministic runs still advertise a low chance of this boundary and a weak mid-level disturbance kicking off some convection over the Sierra Madre Wednesday evening, which could bring some brief showers and thunderstorms across the Northern Ranchlands Wednesday night.

The warmest temperatures of the forecast will be Wednesday afternoon, when highs are expected to soar into mostly the mid/upper 90s, though could hit close to the century mark in a few locations west of US-281. As the high pressure weakens and subsidence aloft decrease a bit to end the work week, temperatures are expected to rise as high as the mid 90s on Thursday and Friday. Yet, factoring in the increased moisture from breezy afternoon southeasterly winds, gusting to 20-30+ mph, a Moderate Heat Risk is expected for most inland areas on Wednesday and Thursday as afternoon heat indices peak around 100-105 F. Lighter onshore winds lead to a Minor to Moderate Heat Risk is anticipated for Friday, with heat indices reaching into the lower 100s across the RGV and inland portions along/east of I-69 E. Highs in the low 80s continue along/near the coast, where a Minor Heat Risk prevails into the afternoon hours through Friday.

On Friday, the shortwave over western Texas ejects over the Southern Plains and a cold front behind the associated surface low pressure systems sweeps southward through Deep South Texas Friday night. Showers and thunderstorms developing ahead of and along the front Friday evening increase chances of rain to as much as a low to medium (30-40%) chance Friday night, with overnight lows falling to the 50s/60s. Breezy to gusty northerly winds along and behind the front continue into Saturday morning followed by gradual improvement into the remainder of Saturday as chances of rain decrease and cooler temperatures are advected into the region. Highs in the 70s on Saturday warm into the low 80s on Sunday and become near average into the beginning of next week as southeasterly winds return by Monday.

A medium risk of rip currents continues through at least Wednesday afternoon and possibly into Friday as waves of 3-4 feet and 6-7 sec. periods prevail. A High Risk of Rip Currents is expected behind the front as well as potential minor coastal flooding through at least this weekend.

AVIATION

(06Z TAFS) Issued at 1217 AM CDT Wed Apr 29 2026

Another round of MVFR ceilings has set up tonight across most of the region. Intermittent periods of VFR ceilings cannot be ruled out, but over all expect MVFR to prevail. VFR should return by mid morning. Southeasterly winds will persist, with occasional gusts up to 25 knots through the forecast period.

MARINE

Issued at 1029 PM CDT Tue Apr 28 2026

Dry weather, moderate to fresh southeasterly winds, moderate (3-5 ft) seas and periods of Small Craft Exercise Caution conditions are expected to continue into Friday. Chances of rain from developing showers and thunderstorms gradually increase throughout Friday to as much as a low to medium (30-60%) chance Friday night into Saturday morning as a cold front passes through. Strong northerly winds arrive with the front Friday night, possibly prevailing into Saturday night, bringing moderate to rough seas as well as Small Craft Advisory headlines. Chances of rain gradually diminish throughout the remainder of Saturday and winds and seas improve into the beginning of next week.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 90 75 89 76 / 0 0 0 0 HARLINGEN 94 73 92 73 / 0 0 0 0 MCALLEN 97 76 95 76 / 0 0 0 10 RIO GRANDE CITY 99 74 96 73 / 0 0 0 10 SOUTH PADRE ISLAND 82 76 82 76 / 0 0 0 0 BAYVIEW/PORT ISABEL 89 74 88 74 / 0 0 0 0

BRO WATCHES/WARNINGS/ADVISORIES

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