textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 555 AM CDT Mon Jun 29 2026

- Afternoon heat indices of around 105-110 F maintain mostly moderate heat risks (level 2 of 4) today. Minor (level 1 of 4) to moderate heat risks are likely by Tuesday.

- Mainly dry conditions prevail. A low chance (15% or less) of sea breeze showers returns later this week on Thursday and Friday.

- A moderate risk of life-threatening rip currents continues through Monday night.

- A Small Craft Advisory is in effect for the Laguna Madre and northern Gulf waters (northward from Port Mansfield 0-60 nm out) until 7 AM Monday morning.

UPDATE

Issued at 1121 PM CDT Sun Jun 28 2026

Update for today's air quality information in discussion.

DISCUSSION

Issued at 1034 PM CDT Sun Jun 28 2026

Broad mid-level ridging over eastern CONUS will dominate the weather pattern through the week, limiting precipitation and maintaining a moderate to minor risk of heat related illness with heat indices in the triple digits. An enhanced pressure gradient will support breezy to gusty conditions through Monday, with southeasterly winds sustained 20-25 mph and gusts 30-35 mph. Winds begin to diminish Tuesday as the pressure gradient relaxes.

Temperatures will remain seasonable for late June/early July, with highs in the upper 90s to low 100s (80s along the coast) and lows in the 70s. Moderate heat risk will persist Monday across deep South Texas with heat indices from 105-110 degF. Heat indices in the triple digits continue through the forecast, with a minor (Ranchlands) to moderate (RGV) risk of heat related illness.

Rain chances remain minimal through midweek, with dry air aloft and subsidence suppressing convective development. By Thursday/Friday, the ridge breaking down will increase support for sea breeze showers along the coast (low chances, less than 20%).

NASA/GMAO aerosol forecasts indicate a plume of Saharan dust intruding over deep South Texas through Monday, which will lead to poor air quality that is unhealthy to sensitive groups.

AVIATION

(12Z TAFS) Issued at 555 AM CDT Mon Jun 29 2026

VFR will prevail through the forecast period at all TAF sites. However, brief periods of MVFR ceilings cannot be ruled out through 13-14Z. Otherwise, a tightening pressure gradient will result in gusty southerly winds by mid to late morning and continuing through the evening hours. Expect wind speeds around 15 to 20 knots with gusts up to 30 knots. Wind speeds should fall near or below 10 knots tonight.

MARINE

Issued at 1034 PM CDT Sun Jun 28 2026

Fresh southeasterly flow with strong gusts will continue adverse marine conditions through Monday. A Small Craft Advisory is in effect through Monday morning, and Small Craft should Exercise Caution conditions will likely continue through Monday night. Moderate seas decrease to slight, and winds lessen to gentle to moderate by midweek. Favorable marine conditions are expected in the latter half of the period, with low (15% or less) rain chances persisting.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 94 79 94 79 / 0 0 0 0 HARLINGEN 97 76 95 76 / 0 0 0 0 MCALLEN 99 79 99 78 / 0 0 0 0 RIO GRANDE CITY 101 77 99 76 / 0 0 0 0 SOUTH PADRE ISLAND 87 81 87 81 / 0 0 0 0 BAYVIEW/PORT ISABEL 92 78 91 78 / 0 0 0 0

BRO WATCHES/WARNINGS/ADVISORIES

TX...None. GM...Small Craft Advisory until 7 AM CDT this morning for GMZ130-132- 135-155-175.