textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 1217 AM CDT Fri Aug 21 2026

- Hot and rain-free conditions will continue through the middle of next week.

- Moderate (level 2 of 4) to major risk (3 of 4) of heat-related impacts 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 1025 PM CDT Thu Aug 20 2026

The 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.

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

(06Z TAFS) Issued at 1217 AM CDT Fri Aug 21 2026

Favorable flying conditions will occur at the aerodromes through the next 24 hours with VFR in place.

MARINE

Issued at 1025 PM CDT Thu Aug 20 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 moderate south to southeast winds and seas of 2 to 3 feet through the period.

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 98 80 99 79 / 0 0 0 0 HARLINGEN 102 75 103 75 / 0 0 0 0 MCALLEN 104 79 105 78 / 0 0 0 0 RIO GRANDE CITY 105 77 105 76 / 0 0 0 0 SOUTH PADRE ISLAND 90 81 90 80 / 0 0 0 0 BAYVIEW/PORT ISABEL 97 78 98 77 / 0 0 0 0

BRO WATCHES/WARNINGS/ADVISORIES

None.