textproduct: Brownsville/Rio Grande Valley

KEY MESSAGES

Updated at 1235 AM CDT Sun Aug 23 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-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 1047 PM CDT Sat Aug 22 2026

A strong 500 mb ridge will meander over southern New Mexico/western Texas and northern Mexico extending over Texas through late next week. This will continue to provide 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 1235 AM CDT Sun Aug 23 2026

VFR conditions are forecast to continue through the period. Light southeasterly winds are forecast to continue through the morning with wind speeds increasing slightly through the afternoon. Brief wind gusts will be possible with the passage of the sea breeze Sunday afternoon.

MARINE

Issued at 1047 PM CDT Sat Aug 22 2026

Favorable marine conditions will prevail along the lower Texas Coast through the period as high pressure continues across the Gulf. Light to occasionally moderate south to southeast winds and low seas are expected through late next week.

FIRE WEATHER

Issued at 1230 PM CDT Sat Aug 22 2026

While we're likely to fall just short of Fire Danger conditions (i.e. 15-20+ 20 foot wind), we're on the razor's edge when considering pulse gusts. Unlike earlier this week, however, the gradient does slacken enough to keep even a reasonable worst-case gust factor to 25 mph along/east of IH-69C/US-281, and 20 mph to the west. But the combination of flash drought, the potential for afternoon RH to fall into the 15-25% range west of IH-69C/US 281 (and 25-35% east of there) as well as re-cured fuels based on visuals and the above-average evaporation rates are enough to keep the wildfire prevention message front and center.

Burn bans remain in effect for all but Kenedy County, and just a spark combined with even a pulse gust could quickly turn into a wildfire that could spread fairly rapidly. Since late July, there were two large wildfires with nearly 1400 acres burned in western Brooks - an area that missed out on two rain events not too far away (southwestern Brooks). The last truly beneficial rain over a decent-sized area was on August 2...and those benefits are long dried up.

Continue to promote wildfire safety and prevention until further notice.

CLIMATE

Issued at 1230 PM CDT Sat Aug 22 2026

How hot, August? Through the 21st, ranking in the top two or three all-time for most available stations. Rival years include 2023 (tops for several locations) and 2009 (tops for McAllen). 2023 remains the hottest meteorological summer (June-August) and astronomical summer (June 21 - September 21, in general)...but 2026 is hot on its heels. Given the expected temperatures to remain around 3 degrees above average through the end of August, several locations may tie or even push ahead of 2023's benchmark.

Here are the current stats for August, through the 21st:

Location (since) August (Rank) Record (year)

Brownsville (1878) 90.0 (2) 90.5 (2023) McAllen (1941) 91.5 (2) 92.3 (2009) Harlingen (1912) 88.6 (5) 90.3 (2023) McCook (1942) 89.3 (4) 90.1 (1998) Port Mansfield (1958) 86.8 (2) 87.3 (2023) Rio Grande City (1897)* 90.3 (3) 93.0 (1901)* Weslaco (1914) 89.5 (2) 90.4 (2023) Raymondville (1913) 89.7 (1) 2026

PRELIMINARY POINT TEMPS/POPS

BROWNSVILLE 99 80 98 80 / 0 0 0 0 HARLINGEN 102 76 102 76 / 0 0 10 0 MCALLEN 105 79 104 79 / 0 0 0 0 RIO GRANDE CITY 105 76 104 77 / 0 0 0 0 SOUTH PADRE ISLAND 89 81 89 81 / 0 0 0 0 BAYVIEW/PORT ISABEL 97 78 96 79 / 0 0 0 0

BRO WATCHES/WARNINGS/ADVISORIES

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