textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 557 AM CDT Tue Apr 28 2026

Key Messages:

* The hottest day of the week will be Tuesday, with a Moderate to Major (Levels 2/4 and 3/4) Heat Risk, as widespread afternoon "real feel" temperatures (heat indices) of 105-110 F are likely, possibly briefly surpassing 110 F across southern portions of the Upper and Middle RGV.

* Above average temperatures continue into this Friday, cooling only by a few degrees beginning Wednesday, bringing a Moderate Heat Risk on Wednesday and a Minor (Level 1/4) to Moderate risk on Thursday and Friday.

* Moderate Risk of Rip Currents continues through at least Tuesday afternoon.

* Cold front arrives possibly Friday night, bringing a low to medium (30-40%) chance of rain Friday night into Saturday morning from developing showers and thunderstorms.

* Much cooler and below average temperatures behind the front from Friday night into next Monday.

DISCUSSION

Issued at 1023 PM CDT Mon Apr 27 2026

A slightly anomalistic mid/upper level high pressure (~591 dam) remains centered over central and eastern Mexico into the middle parts of this week, maintaining strong control over Deep South Texas, with dry and hot conditions prevailing and temperatures running around 5-10 above average into Wednesday; highs soar into the mid/upper 90s along/east of US-281 while upper 90s/lower 100s are anticipated further west. Overnight lows fall to the 70s. The hottest and more dangerous heat indices are progged for Tuesday as breezy southeasterly onshore flow, gusting to 20-30+ mph, and subsidence aloft result in a Moderate to Major (Levels 2/4 and 3/4) Heat Risk, with widespread afternoon heat indices of 105-110 F, though could briefly surpass 110 F near the US/Mexico border in the Middle and Upper RGV. Following, digging mid/upper level troughs over the Great Lakes and another moving from the southern West Coast into the Desert Southwest begin to flatten and weaken the mid-level high, thus easing on subsidence and allowing for temperatures to "cool" to 5 degrees above average, though still reaching into the mid/upper 90s on Thursday and Friday; a Moderate Heat Risk on Wednesday (heat index around 100-108 F) lessens slightly to a Minor (Level 1/4) to Moderate Heat Risk on Thursday and Friday, with indices reaching to near 100 F across the RGV and a bit cooler further north. Looking to escape this brutal heat? Head to South Padre Island! Highs in the low 80s are anticipated along the coast for this timeframe. However, be very cautious if venturing into the Gulf as breezy southeasterly winds, 3-5 foot waves and 6-7 sec. wave periods lead to a moderate risk of rip currents through at least Tuesday afternoon.

On a side note, there is an outside chance of brief passing rain shower and thunderstorm activity Wednesday evening or Wednesday night across portions of the Northern Ranchlands in association with a weak disturbance moving over central Texas. Yet, drier PWAT from sinking air are more likely to suppress convection initiation this far south.

As the trough and associated surface low pressure exit the Desert Southwest and move north of the County Warning Area on Friday, surface high pressure and northerly winds on the low's backside are expected to push a cold front through the region Friday night. Moisture pooling, frontal lift and synoptic forcing aloft ahead of and along the front are currently posing a gradual increase in chances of rain from showers and thunderstorms throughout the daytime Friday to as much as a low to medium (30-40%) chance Friday night into Saturday morning. There could be a chance for some stronger storms, but will be largely dependent on the degree of moisture recovery over the Gulf and mid-levels in wake of the high pressure aloft. Building surface high pressure over the Southern Plains behind the front advects northerly to northeasterly winds and much cooler/below average temperatures Friday night and over the weekend, when overnight lows in the 50s/60s and highs in the 70s/80s.

AVIATION

(12Z TAFS) Issued at 557 AM CDT Tue Apr 28 2026

Low MVFR stratus and generally light southeast winds prevail across Deep South Texas early this morning. MVFR conditions are expected to gradually improve to VFR later morning. Light southeast winds will increase and become breezy later this morning into the afternoon. Some gusts around 30 knots will be possible in the afternoon, especially at BRO/HRL. MVFR ceilings are forecast to return this evening into tonight with southeast winds slowly decreasing after sunset.

MARINE

Issued at 1023 PM CDT Mon Apr 27 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 medium (40-50%) chance Friday night into Saturday morning as a cold front passes through. Strong northerly winds arrive with and behind 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 91 75 91 75 / 0 0 0 0 HARLINGEN 96 73 95 73 / 0 0 0 0 MCALLEN 99 77 98 76 / 0 0 0 0 RIO GRANDE CITY 101 75 100 73 / 0 0 0 0 SOUTH PADRE ISLAND 83 76 83 76 / 10 0 0 0 BAYVIEW/PORT ISABEL 90 74 89 74 / 0 0 0 0

BRO WATCHES/WARNINGS/ADVISORIES

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