textproduct: Austin/San Antonio

KEY MESSAGES

Updated at 132 PM CDT Thu Aug 27 2026

- A Heat Advisory remains in effect for the Coastal Plains and I-35 corridor through 7 PM CDT this evening.

- Low to medium rain/storm chances for most areas mid to late afternoon through this evening and some locations Friday. Otherwise, hot and predominantly dry weather persists over the weekend and the new week.

SHORT TERM

(Tonight through Friday night) Issued at 132 PM CDT Thu Aug 27 2026

Latest satellite images are showing three features of interest: 1) the earlier outflow that affected parts of the northeast Hill Country and vicinity counties such as Lee and Bastrop pushing across the Coastal Plains, 2) the cold front over central Texas pushing southward, and 3) the disturbance over eastern Trans-Pecos area. The first feature (outflow) continues to push to the south, however, it could meet with the seabreeze to get some showers and storms going with daytime heating mid to late afternoon. The second feature which is the cold front is forecast to push to the south for the rest of this afternoon as it gets closer to the Hill Country. The Third feature (cluster of storms Trans-Pecos) is likely to push into portions of the Southern Edwards Plateau for the rest of this afternoon. There is already light rain showing up out there over northwest Val Verde County. All this to say that these features are forecast to prepare the atmosphere to become unstable for the best chances of rain we have had in awhile.

Isolated to scattered showers and thunderstorms are forecast to begin developing mid to late afternoon. Some areas stay dry while others get a bit of relief of the heat with the precipitation. However, the heat is on with temperatures ranging from the mid to upper 90s and up to 100 degrees as of 1 PM. The hottest air temperatures are probably reached along and east of the I-35 corridor, Coastal Plains, and parts of the Rio Grande Plains (up to 104). Maximum heat index values are forecast to range from 108 to 110 with isolated spots getting up to 113. Therefore, the Heat Advisory remains in effect for areas along and east of I-35 corridor and Coastal Plains through 7 PM this evening. If showers and storms begin around 4 PM this afternoon over those locations under the Heat Advisory, then chances are that air temperatures and heat index values drop below criteria. Will monitor this closely.

As far as the shower and storm activity, models are suggesting for outflows to merge (seabreeze and cold front activity) later this afternoon with a line of storms developing near the escarpment and then moving to the southwest. Some storms could be capable of producing wind gusts of 40 to 50 mph and even 60 mph. Also, a few hires solutions are suggesting to get another round of showers and storms later this evening associated with a cluster of storms pushing down across the Southern Edwards Plateau from the San Angelo area. By midnight tonight, all activities should be over. Overnight lows range from the low to upper 70s.

By Friday midday, morning clouds are mostly gone for partly cloudy skies and even sunny skies especially over parts of the Hill Country and vicinity including the Austin metro area. Highs are forecast to range from the upper 90s to 104 degrees. Maximum heat index values are forecast to range from the 108 to 113 as of this package. At this time, I have elected to hold off issuing a Heat Advisory for Friday and wait to see what happens later this afternoon with the airmass that stays in place. Also, there are slight to chances for rain over parts of the Southern Edwards Plateau and portions of the I-35 corridor and Coastal Plains.

LONG TERM

(Saturday through next Thursday) Issued at 132 PM CDT Thu Aug 27 2026

The weekend looks dry with highs in the 90s and up to 103 degrees and maximum heat index around 108 to 110. The next chance for rain comes early next week (Monday) when an upper inverted level disturbance moves from the northern Gulf into the east Texas coast. Then on Tuesday, chances of rain return with increased moisture in place and the seabreeze driving the convective activity. The same pattern is anticipated for Wednesday and Thursday. High temperatures remain in the 90s and up to 102 degrees during the work week.

AVIATION

(18Z TAFS) Issued at 1230 PM CDT Thu Aug 27 2026

Forecast package largely remains on track from previous issuance. Main changes were to delay start time for rain chances for I-35 TAF sites. Otherwise kept VRB winds as prevailing as the frontal boundary looks to stall/slowly move across the area late this afternoon. Should storms form we could see numerous outflow boundaries across the area leading to erratic winds across the terminals. Additionally, we could see brief MVFR cigs as the cloud deck expands from any leftover convection as it moves from north to south. Even after the boundary passes we will still see light and VRB winds until around 16/18Z tomorrow. By this time we should finally see a more easterly prevailing wind direction. For KDRT have easterly winds prevailing before becoming more southeasterly once the boundary passes. Rain/storm chances are a bit more uncertain this far west but if they do occur then it wouldn't be until around 01Z. We will continue to monitor and amend as needed.

PRELIMINARY POINT TEMPS/POPS

Austin Camp Mabry 78 102 78 101 / 20 10 0 0 Austin Bergstrom Intl Airport 77 101 77 100 / 20 10 0 0 New Braunfels Muni Airport 75 101 76 100 / 30 10 10 0 Burnet Muni Airport 75 99 75 98 / 10 0 0 0 Del Rio Intl Airport 78 102 78 100 / 30 20 10 0 Georgetown Muni Airport 77 100 77 100 / 20 0 0 0 Hondo Muni Airport 75 99 75 98 / 30 20 10 0 San Marcos Muni Airport 76 101 76 100 / 20 10 0 0 La Grange - Fayette Regional 77 101 77 100 / 40 10 0 0 San Antonio Intl Airport 77 100 77 99 / 30 20 10 0 Stinson Muni Airport 78 102 78 101 / 30 20 10 0

EWX WATCHES/WARNINGS/ADVISORIES

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