textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 625 AM CDT Sat Aug 22 2026

- Hot and rain-free conditions will continue through late next week. - Moderate (level 2 of 4) to major risk (3 of 4) of heat-relatedimpacts through the period with peak afternoon heat indices generally between 105 to around 110 degrees.

- The combination of low minimum relativity humidity values, dry fuels, and very hot temperatures could lead to the potential for rapid wildfire spread through the period.

DISCUSSION

Issued at 1038 PM CDT Fri Aug 21 2026

A 500 mb ridge will meander over the Four Corners region through the middle of next week. This will continue to provide strong subsidence across Deep South Texas with very hot and mainly rain-free conditions through forecast period. Daily high temperatures are expected to reach the upper 90s to around 105 degrees, except near the coast. The combination of the very hot temperatures and elevated dewpoint temperatures will support heat indices generally between 105 to 110 degrees each afternoon. Heat indices may briefly reach 111+ at a few locations in the afternoon, but temperatures should remain just below Heat Advisory criteria each day. Widespread Moderate (Level 2 of 4) to Major (Level 3 of 4) Heat Risk expected through the weekend and into the middle of next week. Some pockets of Extreme (Level 4 of 4) Heat Risk will be possible by late next week.

The combination of low minimum relativity humidity values, dry fuels, and very hot temperatures could lead to the potential for rapid wildfire spread through the period.

AVIATION

(12Z TAFS) Issued at 625 AM CDT Sat Aug 22 2026

VFR conditions are forecast to continue though the period. Light southeasterly winds are forecast to continue through the morning, with speeds and gusts increasing this afternoon. Light and variable winds are forecast tonight.

MARINE

Issued at 1038 PM CDT Fri Aug 21 2026

A slightly enhanced pressure gradient over the western Gulf may produce Small Craft Should Exercise Caution conditions on the Laguna Madre at times. Otherwise, mariners can expect generally favorable conditions with moderate south to southeast winds and seas of 2 to 3 feet through the period.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 100 79 98 79 / 0 0 0 0 HARLINGEN 104 75 103 75 / 0 0 0 0 MCALLEN 106 78 105 78 / 0 0 0 0 RIO GRANDE CITY 106 76 105 76 / 0 0 0 0 SOUTH PADRE ISLAND 90 80 89 81 / 0 0 0 0 BAYVIEW/PORT ISABEL 98 77 97 78 / 0 0 0 0

BRO WATCHES/WARNINGS/ADVISORIES

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