textproduct: Austin/San Antonio

KEY MESSAGES

- Mostly dry this weekend, then stormy with heavy rainfall possible for much of next week.

- Increasing humidity and heat indices through Tuesday, with some spots feeling like 100-105+ Sunday, Monday, and Tuesday.

SHORT TERM

(Today through Saturday) Issued at 129 AM CDT Fri May 15 2026

The capping inversion is expected to hold over the area Friday into Saturday, but some higher terrain activity in Mexico and West TX could threaten to send a stray storm toward the Val Verde County border Friday evening. Low amplitude ridging over TX continues to slowly transition towards a less stable SW flow aloft pattern going into the weekend. A gusty south breeze will continue to fill the nighttime air with increasing gulf moisture, but for Friday, the layer of dry air at the top of the mixed layer will be less effective in mixing down to lower afternoon surface dew points, so the warm conditions for the afternoon will carry a higher humidity and heat index. They will be somewhat typical for a mid May afternoon Friday, but the increasing trend will continue. Low clouds will unable to get started Thursday morning but should cover a good portion of the CWA by the daybreak hours Friday and Saturday. By Saturday afternoon the heat indices will get to the point where we may need to put out some cautionary messaging those spending extra time outdoors.

LONG TERM

(Saturday night through Thursday) Issued at 129 AM CDT Fri May 15 2026

The continued warming and moisture loading will continue to escalate Sunday, and conditions could send heat index values to the near the points of consideration for heat advisories Monday and Tuesday. We think the HI thresholds of 110 West & 108 East for our area are mostly safe but that call should be more easy to make by Sunday.

Saturday night into Sunday the troughing developing upstream over the Wrn CONUS sends a shortwave piece of energy across the Srn Rockies into the Central Plains, but at the same time will lower heights over W and Central TX. Deterministic models do not show an impact on the dry-line, but with moisture continuing to load up over Central TX, do show a low chance of streamer convection cluster over our central counties. While there is skepticism over whether the cap can be overtaken at this spot, it's only a 15-20 percent indication. By Monday afternoon the broad SW aloft pattern over TX has made the expansion to make any location in our CWA a candidate for an isolated storm or two. Capping is still expected to be fairly tough to overcome at this time, and confidence on this period remains too low for us to 2nd guess the NBM guidance. By Tuesday however, there should be enough escalation from activity erupting off higher terrain and a potential area of convection possibly propagating south from a NW TX frontal boundary that we should see better coverage. And here we go throughout the full work week of storm initiation driven by high Pwat value pooling, MCV's, MCS's, and remnant boundaries to paint a stormy, but vague picture. It is assumed that one trend will be more predictable in that the areas of daily convection should take a toll on the temperatures and heat indices. There could be a mid-week front, but there isn't enough model support to specify, and if the front did get here, the impact on temperatures would probably mainly cloud-cover dependent.

At some point we'll also want to address a potential heavy rain threat. Given a wide variety of model solutions, we'll assume coverage begins fairly low, which might favor a slow start and appropriate messaging to point more towards the middle of the week.

AVIATION

(12Z TAFS) Issued at 538 AM CDT Fri May 15 2026

MVFR ceilings have settled over the Austin and San Antonio areas. DRT remains VFR and should remain VFR through the upcoming TAF period. VFR skies will return to Austin and San Antonio by late morning. Winds will increase and become gusty by late morning. Gusty winds should continue into the evening. MVFR ceilings will return early in the overnight period tonight.

PRELIMINARY POINT TEMPS/POPS

Austin Camp Mabry 92 71 92 75 / 0 0 0 10 Austin Bergstrom Intl Airport 92 72 92 77 / 0 0 0 10 New Braunfels Muni Airport 92 69 91 75 / 0 0 0 0 Burnet Muni Airport 88 69 87 73 / 0 0 0 0 Del Rio Intl Airport 96 72 94 76 / 0 0 0 0 Georgetown Muni Airport 90 71 90 74 / 0 0 0 0 Hondo Muni Airport 93 70 92 75 / 0 0 0 0 San Marcos Muni Airport 92 71 92 76 / 0 0 0 0 La Grange - Fayette Regional 91 71 90 76 / 0 0 0 10 San Antonio Intl Airport 93 71 92 76 / 0 0 0 0 Stinson Muni Airport 94 71 92 76 / 0 0 0 0

EWX WATCHES/WARNINGS/ADVISORIES

None.