textproduct: Austin/San Antonio

KEY MESSAGES

Updated at 1212 AM CDT Sun Sep 20 2026

- Low chances (15-30%) for showers or storms across the Hill Country and Southern Edwards Plateau from Sunday night into Tuesday.

- Low chances (10-30%) for spotty rain across South Central Texas through next week with most staying dry.

- Above average temperatures continue into next weekend.

SHORT TERM

(Today through Monday) Issued at 1212 AM CDT Sun Sep 20 2026

Another warm day is in the cards for Sunday. Southwesterly flow aloft should continue to push cirrus across the area, which will blunt insolation some during the afternoon. High temperatures are still forecast to reach the 90s across South Central Texas with a few isolated spots briefly nudging above 100F. A shortwave trough embedded within the southwesterly flow will track across the Edwards Plateau late afternoon into the evening. This is expected to trigger showers and thunderstorms, beginning primarily northwest of the area closer to the dry line. While this area has better kinematic support for development, the zone of storm development could be sensitive to where the cirrus is thinnest, which may shift storm formation closer to the Hill Country as depicted in some of the REFS members. In either case, weak steering flow indicates a few storms could slowly push into the Hill Country and southern Edwards Plateau in the evening hours before instability wears off around midnight and the potential fizzles out. Rain chances range from 15 to 30 percent over those areas Sunday night. While severe weather is unlikely given the lack of noteworthy wind shear, gusty winds are possible with high 1200+ J/kg DCAPE depicted in the HREF means. Slow storm movement may also support locally heavier rains.

The passage of the shortwave trough should weaken the overhead ridge some on Monday, though emerging anticyclonic flow at Z250 over Mexico and a lack of additional upstream impulses of energy means the ridge will have some time to recuperate. Temperatures will stay unseasonably hot with highs remaining in the 90s to around 100F and lows not varying much from the consistent 70s. Despite the lack of vorticity aloft, a weak front is forecast to move into North Texas and then slow to a stall beneath the ridge over West Central Texas, possibly interacting with any leftover boundaries deposited by Sunday night's convective activity. This provides a window for spotty showers and thunderstorms Monday afternoon/evening, again for the southern Edwards Plateau and Hill Country, and possibly into the Austin metro area as well. Given the lack of strong forcing, confidence is low and rain chances range from 15 to 30 percent.

AVIATION

(06Z TAFS) Issued at 1212 AM CDT Sun Sep 20 2026

VFR ceilings are expected, however there is a non-zero chance for some MVFR ceilings at AUS. Winds remain east-southeasterly around 5-10 kts, but will likely be calm to less than 5 kts through mid- morning. High clouds from decaying convection out west will result in BKN clouds at 25k feet through the night.

PRELIMINARY POINT TEMPS/POPS

Austin Camp Mabry 99 76 98 76 / 0 10 20 20 Austin Bergstrom Intl Airport 99 76 98 75 / 0 10 20 10 New Braunfels Muni Airport 98 74 99 73 / 0 10 10 10 Burnet Muni Airport 95 73 94 72 / 10 20 30 20 Del Rio Intl Airport 99 76 100 75 / 10 10 0 10 Georgetown Muni Airport 97 75 96 75 / 0 10 20 20 Hondo Muni Airport 96 73 97 73 / 0 10 0 10 San Marcos Muni Airport 98 74 98 74 / 0 10 10 20 La Grange - Fayette Regional 99 75 100 75 / 0 10 10 10 San Antonio Intl Airport 97 76 98 76 / 0 10 10 10 Stinson Muni Airport 99 75 100 75 / 0 0 10 10

EWX WATCHES/WARNINGS/ADVISORIES

None.