textproduct: Austin/San Antonio

KEY MESSAGES

Updated at 540 AM CDT Fri Aug 21 2026

- Heat Advisory in effect form the northern Hill Country, I-35 Corridor, and Coastal Plains Thursday-Sunday.

- Brief and isolated storms possible over Central TX late Saturday.

- August heat wave continues with no significant rain or heat relief in sight.

SHORT TERM

(Today through Saturday) Issued at 1206 AM CDT Fri Aug 21 2026

The massive subtropical ridge over the Wrn CONUS continues to slowly edge eastward into West TX. A weak meridional flow over the Central CONUS and a back door front stalling over NE TX will generate enough moisture pooling for some convection, with probably an extra element of compressional heating coming our way for today. Thursday's high temps topped out into the low end side of Heat Advisory for both ambient and heat index criteria, and the numbers may go up another degree or two today with the unstable forcing well upstream to our NE. Overnight lows may also trend up a degree or two with the stagnant are and low non-convective wind speeds. For Saturday, expect more of the same, except that area of instability to the NE might just get close enough for a stray storm or two, and possibly some strong outflow winds.

LONG TERM

(Saturday night through Thursday) Issued at 1206 AM CDT Fri Aug 21 2026

The brief opportunity to see a storm or two should abate by late evening and we go right back into upper ridge dominance after the moisture pooling disperses for Sunday. The ridge of high pressure will hold over the region over the rest of the weekend and continue building as the work week kicks off. By mid-week, the center will slide between New Mexico and Texas keeping a warm, sunny pattern on tap for the region. The scale of the heat will need to be monitored in upcoming forecast cycles in case the heat wave threatens some daily maximum temperature records.

AVIATION

(12Z TAFS) Issued at 540 AM CDT Fri Aug 21 2026

VFR flight conditions prevail. A few low early morning clouds have developed east of KAUS this morning but not expecting any impacts to the terminals due to these low clouds. Late today through tonight may see some high clouds filter, otherwise anticipate patchy low clouds to again develop towards early Saturday morning. Expect for a light to modest south-southeast flow to continue with sustained speeds sitting around 10 kts or less with a few infrequent gusts to above 15 kts.

PRELIMINARY POINT TEMPS/POPS

Austin Camp Mabry 104 79 105 80 / 0 0 20 20 Austin Bergstrom Intl Airport 103 79 104 79 / 0 0 20 20 New Braunfels Muni Airport 104 76 104 77 / 0 0 10 10 Burnet Muni Airport 103 77 104 77 / 10 0 20 20 Del Rio Intl Airport 103 78 105 78 / 0 0 0 0 Georgetown Muni Airport 102 79 104 80 / 10 0 20 20 Hondo Muni Airport 102 76 103 76 / 0 0 0 0 San Marcos Muni Airport 103 77 103 77 / 0 0 10 10 La Grange - Fayette Regional 104 77 104 78 / 0 0 20 20 San Antonio Intl Airport 102 79 103 78 / 0 0 0 10 Stinson Muni Airport 103 78 104 78 / 0 0 0 0

EWX WATCHES/WARNINGS/ADVISORIES

Heat Advisory until 7 PM CDT Sunday for TXZ171>173-191>194- 205>209-220>225.