textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 650 PM CDT Thu Apr 30 2026

Key Messages:

* Heat risk (Minor to Moderate) continues through Friday, before a cold front arrives late Friday night.

* Pleasant temperatures in the 70s and 80s are expected this weekend.

* There is a moderate (30-60%) chance of precipitation Friday evening into Saturday morning.

DISCUSSION

Issued at 1231 PM CDT Thu Apr 30 2026

High pressure continues to break down over the region as a shortwave approaches from the West. As a result, the pressure gradient remains tightened which will give way to breezy conditions this afternoon and tomorrow afternoon. Winds will be southeasterly through Friday evening, continuing the stream of warm, humid air into Deep South Texas. For this reason, heat indices are expected to remain above actual temperatures through Friday evening. A Minor (level 1 of 4) to Moderate (level 2 of 4) Heat Risk is expected the remainder of today and tomorrow.

This shortwave is expected to pass through the Central Plains Friday, which will bring a cold front to Deep South Texas. The front is expected to arrive late Friday evening, and will bring noticeably cooler air to the area this weekend. Saturday's highs will be pleasant in the mid to upper 70s and Sunday will be in the low 80s. High temperatures will remain in the low to mid 80s for Monday before warming into the lower 90s for Tuesday. Saturday and Sunday night lows will be cool, with some areas getting down into the mid- 50s.

Precipitation chances late Friday evening into Saturday morning are trending a little bit higher than previous guidance indicated. Probabilities have increased to between 30-60%, with the highest chances closest to the coast early Saturday morning. CAMs seem to be in agreement that there will be widespread light showers that form early Saturday morning following the frontal passage, with the most coverage over the eastern Lower Rio Grande Valley. Precipitation totals should be relatively small, with most areas receiving no more than half an inch. However, locally heavier amounts of up to 1.5 inches are possible if any isolated heavier showers or thunderstorms form.

What is less certain is whether there will be any isolated shower/thunderstorm activity ahead of the cold front Friday evening. The Storm Prediction Center does include all of Deep South Texas in a general thunderstorm risk for Friday. However, most of the CAM guidance shows little to no development, but the latest HRRR guidance does indicate a storm or two could form off the Sierra Madre and move into the Western Ranchlands Friday evening. If this threat does materialize, nothing severe is expected at this time. While there is sufficient CAPE (with values exceeding 2500 J/kg in some areas) and ample moisture, wind shear will be too low to support stronger storm dynamics. In addition, a strong capping inversion will be in place, which is typical for this area this time of year.

Beach hazards are also expected with the cold front. Elevated surf and rip currents are expected this weekend.

AVIATION

(00Z TAFS) Issued at 650 PM CDT Thu Apr 30 2026

Gentle to moderate southeasterly winds continue this evening into the next couple of hours, around 10-15 knots, before settling around 5-10 knots overnight. Broken to overcast MVFR ceilings are likely to drop down to MVFR tonight, possibly lowering to IFR at KMFE and KBRO, with the greatest IFR probabilities at KMFE. Otherwise, scattered to broken VFR skies gradually return to all terminals by mid to late Friday morning as southeasterly winds pick back up to around 10-15 knots by the afternoon.

MARINE

Issued at 1231 PM CDT Thu Apr 30 2026

SCEC conditions are currently being observed in both the Bay and the Gulf, and are expected to continue intermittently over the next few days due to a tightened pressure gradient. Small Craft Advisories will likely be needed Friday evening into Saturday morning due to a frontal passage. Conditions are then expected to become more favorable by Monday as winds and seas calm. However, some intermittent SCEC is possible by mid-week.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 76 92 61 74 / 0 0 60 40 HARLINGEN 73 94 59 76 / 0 10 60 20 MCALLEN 77 96 62 77 / 0 10 60 20 RIO GRANDE CITY 75 93 59 77 / 10 20 40 10 SOUTH PADRE ISLAND 76 83 66 73 / 0 0 60 40 BAYVIEW/PORT ISABEL 74 90 61 74 / 0 10 60 30

BRO WATCHES/WARNINGS/ADVISORIES

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