textproduct: Austin/San Antonio

KEY MESSAGES

Updated at 123 PM CDT Thu Sep 10 2026

- Low rain chances today and Friday for the Coastal Plains into the Hill Country and southern Edwards Plateau.

- Temperatures remaining above normal into next week with concerns for maximum temperatures and peak heat index values near Heat Advisory levels this weekend.

- The forecast trends drier through the weekend with very low rain chances confined to the Coastal Plains.

SHORT TERM

(Tonight through Friday night) Issued at 123 PM CDT Thu Sep 10 2026

A weak mid-level disturbance is expected to drift slowly near the Texas Coastal Bend through Friday. The 12Z hi-res models have continued to trend towards lower rain coverage from this system in our region, though with ridging staying weak rain chances remain depicted for portions of South-Central Texas from isolated to scattered showers and storms. Those chances are highest in the Coastal Plains closest to the weak disturbance through Friday (around 30 percent), though a secondary region for potential spotty convection exists over the Hill Country. On Friday, northwesterly flow and potential outflow boundaries from a decaying front over West-Central/North Texas could set up additional opportunities for rain over the Hill Country, Edwards Plateau, and potentially the Interstate 35 corridor. The CAM guidance (outside of the WRFs) has not been especially enthusiastic regarding rain coverage, though with troughing staying over the area and capping remaining weak, we have introduced low-end chances (around 20 percent) for isolated showers and storms centered over the Hill Country Friday afternoon/evening. As is typical for disorganized warm-season convection, there may be a few spots of gustier conditions and pcokets with around an inch of rain, but most will stay dry under sunny conditions.

Temperatures will stay hot through the workweek with highs in the mid 90s to lower 100s and lows in the 70s. A few spots in the Coastal Plains and Rio Grande Plains may see peak heat index values near 108F.

LONG TERM

(Saturday through next Thursday) Issued at 123 PM CDT Thu Sep 10 2026

Model outputs and statistical aids have continued to suggest that heat will subtly rise to a peak on Saturday, concurrent with the strengthening of ridging over the southwestern US and displacement of warm 850mb temperatures eastward. The coverage of triple-digit highs is expected to be at their greatest extent Saturday with highs in the 100F to 103F range over the I-35 corridor and Rio Grande Plains. Without much deep-layer dryness to lower humidity, heat indices could approach Heat Advisory criteria across the I-35 corridor, Coastal Plains, and Rio Grande Plains. Ambient temperatures may decrease by a few degrees after Saturday as a humid southerly flow intensifies, but the added humidity may keep heat indices elevated into early next week.

Next week, Z500 heights increase over the area as ridging strengthens, but the focus of that ridging across ensembles is centered over the southeastern US. This keeps a deep-layer southeasterly wind over our area, maintaining a humid airmass and flow off the Gulf. This will keep a low chance for occasional seabreeze showers over the Coastal Plains, but most of South-Central Texas will tend to stay dry. Expect high temperatures to stay in the 90s to around 100F with lows remaining abnormally mild in the mid to upper 70s for most.

AVIATION

(18Z TAFS) Issued at 1225 PM CDT Thu Sep 10 2026

Primary focus was to keep southwesterlies in place at AUS, SAT, and SSF through 21Z as winds have been more persistent than LAMP guidance. Winds should swing more east-southeasterly by the mid to late afternoon as the seabreeze works inland. A flip back to south-southwesterly is expected after midnight at the I-35 sites with perhaps FEW stratus at 2000 ft. VFR ceilings are expected through the period at this time.

PRELIMINARY POINT TEMPS/POPS

Austin Camp Mabry 77 100 77 102 / 0 10 0 0 Austin Bergstrom Intl Airport 76 100 77 101 / 0 10 0 0 New Braunfels Muni Airport 76 99 76 100 / 0 10 0 0 Burnet Muni Airport 75 97 75 98 / 10 20 0 0 Del Rio Intl Airport 78 102 79 103 / 0 0 0 0 Georgetown Muni Airport 77 99 78 101 / 10 20 0 0 Hondo Muni Airport 76 100 75 100 / 10 0 0 0 San Marcos Muni Airport 76 100 77 100 / 0 10 0 0 La Grange - Fayette Regional 76 99 78 99 / 10 10 0 10 San Antonio Intl Airport 78 99 77 100 / 10 10 10 0 Stinson Muni Airport 77 101 78 102 / 10 10 0 0

EWX WATCHES/WARNINGS/ADVISORIES

None.