textproduct: Austin/San Antonio

KEY MESSAGES

- Flood Watch remains in effect for portions of the Coastal Plains into this evening with pockets of heavy rainfall and high hourly rain rates possible.

- Hazardous heat is possible later this week, especially on Thursday. Practice heat safety.

- Dry weather returns midweek for most of South Central Texas before chances return Friday and this weekend.

SHORT TERM

(Tonight through Wednesday night) Issued at 122 PM CDT Tue Jun 16 2026

The tropical disturbance (recently designated Potential Tropical Cyclone One) that helped to supply the anomalous moisture across the region over the past few days was centered along the South Texas coast as of 1 PM CDT Tuesday and is presently drifting generally northeast towards the Gulf. The strong onshore flow of moisture over the eastern half of the low-pressure area is helping to drive a few tropical rainbands into the Coastal Plains, and a Flood Watch remains in effect for some of our Coastal Plains counties through 7 PM today with the potential of locally heavier rain amounts up to around 4 inches. To the west, northerly flow associated with a ridge centered over the SW US is helping to act as a western boundary to this moisture, and this is depicted well on ALPW imagery as drier mid-level air spreads across West and Central Texas. A few tropical showers may reach as far inland as the I-35 corridor with the aid of daytime heating as some low-level moisture slips beneath the ridging aloft, but this should fizzle out in the evening. The plume of moisture will continue to move east outside of our area as the tropical disturbance continues eastward, eventually bringing the heavy rain threat to an end tonight.

On Wednesday, drier mid-level air should funnel southward across the area, carried by north winds aloft rearward of the outgoing PTC One. Sunnier skies, particularly over the western half of our warning area, will support a warmer day with highs generally in the 90s. A few spots along the Rio Grande could get close to 100, while stickier clouds over the Coastal Plains trailing the nearby tropical system should keep some areas from rising above the 80s. Despite the overall drier conditions, the persistence of southerly low-level flow and the lack of a stronger trough nearby means high dew points will remain in our area, leading to heat indices during the day Wednesday to push into the 100-105F range for much of South-Central Texas. Evapotranspiration from recent rains will likely contribute to this humid heat. A few locations along the Rio Grande may see heat indices briefly approaching the 110F mark late afternoon tomorrow.

LONG TERM

(Thursday through next Tuesday) Issued at 122 PM CDT Tue Jun 16 2026

Thursday is on track to be the hottest day of the week over South-Central Texas, and potentially the hottest day of the summer so far for portions of the Edwards Plateau and along the Rio Grande. Troughing over the northern tier of CONUS is forecast to dislodge a lobe of warm air aloft from the Rockies, reaching our area during the day. Beneath this air, a thermal low will increase humid southerly flow over South-Central Texas, resulting in a strong overlap of heat and high humidity leading to potentially hazardous conditions. Heat indices are expected to rise sharply Thursday afternoon, reaching as high as as the 105 to 115 range for much of South-Central Texas. The issuance of a Heat Advisory will likely be needed for Thursday as the resulting heat risk reaches Major levels. Practice heat safety and make sure you have ready access to cooling and hydration.

The hot airmass becomes a little more diffuse Friday, but the day should still be quite hot and may also necessitate a Heat Advisory with the current blend of models still showing heat indices in spots in the 105 to 115 range, though not as widespread as Thursday. The medium range guidance is in fairly decent agreement that a weak disturbance aloft or residual shower/storm activity from a convective outflow boundary or front will approach the area from the north on Friday, leading to an increase in rain chances. Despite ridging expanding over our area, a mid-level trough could bring isolated to scattered rain and storm chances this weekend, and some of this rain could be heavy as filaments of tropical moisture continue to stick around.

Early next week, a broader shift to more zonal flow should set up a drier weather pattern. Hot weather is expected to continue through the forecast period, and without any convincing wind shift to clear out the moisture, a prolonged period of persistent heat near or at hazardous levels is possible. Continue to practice heat safety.

AVIATION

(18Z TAFS) Issued at 1236 PM CDT Tue Jun 16 2026

VFR conditions are forecast for all local area sites through late this evening. MVFR and IFR cigs are forecast to develop overnight and stay through Wednesday morning. Light northeast to east winds are forecast to persist along the I-35 corridor terminals through tonight and then becoming light and variable overnight through Wednesday morning. For KDRT, light and variable winds are forecast for this afternoon and then a light southeast flow develops to stay through Wednesday morning.

PRELIMINARY POINT TEMPS/POPS

Austin Camp Mabry 74 92 78 96 / 0 0 0 0 Austin Bergstrom Intl Airport 74 92 78 96 / 0 0 0 0 New Braunfels Muni Airport 72 91 76 96 / 0 0 0 0 Burnet Muni Airport 72 92 76 96 / 0 0 0 0 Del Rio Intl Airport 74 98 78 102 / 0 0 0 0 Georgetown Muni Airport 73 91 77 96 / 0 0 0 0 Hondo Muni Airport 72 92 77 96 / 0 0 0 0 San Marcos Muni Airport 73 92 77 96 / 10 0 0 0 La Grange - Fayette Regional 74 90 78 96 / 10 10 10 0 San Antonio Intl Airport 73 92 77 96 / 0 0 0 0 Stinson Muni Airport 73 92 78 96 / 10 0 0 0

EWX WATCHES/WARNINGS/ADVISORIES

Flood Watch until 7 PM CDT this evening for TXZ209-222>225.