textproduct: Austin/San Antonio

KEY MESSAGES

Updated at 1258 PM CDT Sun Sep 13 2026

- A Heat Advisory is in effect through 7 PM today for areas generally along and east of the Interstate 35 corridor. Another Heat Advisory has been issued for the same locations Monday from 12 PM to 7 PM.

- Low rain chances (10-20%) for the I-35 corridor and coastal plains through Monday. Then rain chances remain confined to the coastal plains through the week.

- Humid morning conditions and above average temperatures continue through the the week.

SHORT TERM

(Tonight through Monday night) Issued at 1258 PM CDT Sun Sep 13 2026

The ridge has shifted over North Texas today and will continue an eastward progression before stalling over the southeastern US tomorrow into the middle of the week. Continued hot and mainly dry conditions are forecast in the short term period. Highs will be similar this afternoon and tomorrow from the mid 90s in the Hill Country and southern Edwards Plateau to the upper 90s up to 104 degrees elsewhere. For the I-35 corridor and Coastal Plains, heat index values will rise to Heat Advisory levels from the 108-111 degree range both days. The Heat Advisory remains in effect through 7 PM today and another Heat Advisory has been issued for tomorrow for the same locations.

The vast majority of the area is expected to remain dry today and tomorrow, though low (10-20%) chances for rain do exist from the I- 35 corridor into the coastal plains. The coastal plains is the more likely culprit for any rain due to the seabreeze, but as seen yesterday cannot rule out a storm or two further west. Any activity will end near sunset with the loss of daytime heating.

LONG TERM

(Tuesday through next Sunday) Issued at 1258 PM CDT Sun Sep 13 2026

Ridging remains centered over the Lower Mississippi and Tennessee Valleys through Wednesday, then shifts further west Thursday before extending back towards South Central Texas late week. Triple digit heat continues Tuesday for much of the area, then highs ease slightly mid to late week, though still remain above normal for mid- September. We'll need to keep an eye on heat index values Tuesday and possibly Wednesday as they still creep towards the 105-108 degree mark across the I-35 corridor and coastal plains. Rain chances remain largely confined to the coastal plains each afternoon until a potential surge in moisture/PWATs moves across the area Thursday bringing chances for rain further inland.

AVIATION

(18Z TAFS) Issued at 1258 PM CDT Sun Sep 13 2026

Winds will remain rather breezy this afternoon out of the southeast. A few gusts up and over 20 kts are possible. Opted to introduce another PROB30 thunderstorms and gusty winds accompanying those storms if they do impact terminals from 22-01Z. MVFR ceilings will likely develop closer to 06Z as the trend from last night has shown that low level moisture and clouds have been quicker to form than LAMP and NBM guidance indicate.

PRELIMINARY POINT TEMPS/POPS

Austin Camp Mabry 78 101 78 102 / 10 10 0 0 Austin Bergstrom Intl Airport 77 100 77 101 / 10 10 0 0 New Braunfels Muni Airport 75 99 75 100 / 20 10 0 0 Burnet Muni Airport 74 97 74 98 / 10 10 0 0 Del Rio Intl Airport 77 100 77 102 / 0 0 0 0 Georgetown Muni Airport 77 100 77 100 / 10 10 0 0 Hondo Muni Airport 75 99 75 100 / 10 10 0 0 San Marcos Muni Airport 76 100 75 101 / 20 10 0 0 La Grange - Fayette Regional 77 99 77 100 / 20 20 10 10 San Antonio Intl Airport 78 99 78 100 / 10 10 0 0 Stinson Muni Airport 78 101 77 102 / 10 10 0 0

EWX WATCHES/WARNINGS/ADVISORIES

Heat Advisory until 7 PM CDT this evening for TXZ173-191>194- 205>209-220>225.

Heat Advisory from noon to 7 PM CDT Monday for TXZ173-191>194- 205>209-220>225.