textproduct: Austin/San Antonio

KEY MESSAGES

- Lingering low to medium (20-40%) rain and storm chances for this afternoon through mid Sunday morning before a drier pattern establishes across the region

- Summer heat featuring elevated heat indices continues through next week

SHORT TERM

(Tonight through Sunday night) Issued at 135 PM CDT Sat Jun 20 2026

Recent short term guidance suggests that isolated to scattered convection continues to move just to our south in association with a disturbance over Corpus' area. Some of this convection has and may continue making it into our Coastal Plains area. PWATs are very high around 2 to 2.2 inches across the region so these showers and thunderstorms will be capable of producing torrential rainfall yet again. As such, WPC has upgraded parts of our region to a level 2 of 4 risk of excessive rainfall basically along and east of Hwy 77 with the rest of our area still in a level 1 of 4 risk. Short range guidance has been consistent in storms continuing to form later this afternoon before dissipating this evening. Though as it stands not sure how potent these storms will be as cloud cover has been pretty dense across the region for most of this morning. Additionally, the atmosphere has been pretty worked over from the overnight convection that we had across the area. We are starting to see a few breaks and allowing temps to warm into the mid to upper 80s. However confidence remains medium to low on if convection forms later this afternoon. Tonight whatever convection forms should be waning as we lose daytime heating and the disturbance starts to move further east of our area.

Early Sunday we could see some more chances of scattered showers and thunderstorms as another disturbance looks to impact our area mainly in the morning hours. By Sunday afternoon we could see lingering convection before finally drying out by Sunday evening. A persistent south to southeasterly flow will continue to help keep temperatures holding above average and remaining very warm and with humidity added in, the heat indices will be elevated again Sunday. It's possible that we may need a Heat Advisory for the I-35 Corridor and the Coastal Plains for this timeframe. However still plenty of uncertainty regarding if and when these showers/storms form and how long cloud cover sticks around. More cloud cover reduces the hazardous heat impact whereas less cloud cover and more sun increases chances for hazardous heat products to be issued. We will continue to monitor this and assess as needed.

Regarding temperatures most should remain in the upper 80s to low 90s for highs for Sunday with heat indices once again hovering around the 100-107 degree range, with the highest values felt out across the Coastal Plains. Lows tonight and Sunday night will remain very mild and humid with upper 70s to near 80 possible.

LONG TERM

(Monday through next Saturday) Issued at 135 PM CDT Sat Jun 20 2026

For the long term, mid-level ridging will remain anchored through much of the period to our west across Northern Mexico to perhaps near or just south of the Arizona/New Mexico border. For Monday this will allow all of our area to heat up and remain dry. The eastern extent of this ridge will continue pushing into West Texas through the period. For us, We should stay just to the east of this ridge allowing our area to continue to remain mostly rain free. However we will be under northerly flow aloft so we will have to watch and see if any disturbances and convection from our north tries to swing southward into our area. Otherwise we should stay just below heat advisory criteria for the rest of the forecast with highs in the mid to upper 90s and heat indices in the 100-107 degree range for most. Overnight lows will continue to be very warm and humid in the mid to upper 70s with returning low stratus occurring most nights from late each overnight before dissipating each morning. Overall the long term part of the forecast remains dry giving us a nice break and a much needed chance to start drying out across the area.

AVIATION

(00Z TAFS) Issued at 620 PM CDT Sat Jun 20 2026

Isolated hit or miss showers persist across South-Central Texas this evening but activity should wane in the next few hours with the loss of daytime heating after sunset. VFR flight conditions continues through at least midnight at the TAF sites before low clouds develop and expands across the region with MVFR to IFR ceilings. With these low clouds, a cluster of isolated to widely scattered rain showers could be possible from the early morning into the mid-morning time frame at the I-35 sites (KAUS, KSAT, and KSSF). KDRT is expected to remain dry. Flight conditions are to return to VFR levels into Sunday afternoon with few to sct mid-level cumulus. The south-southeast to east-southeasterly flow will subside after sunset but will pick up with the daytime heating into and through Sunday afternoon. Winds could gust to the 20 to 25 kt range.

PRELIMINARY POINT TEMPS/POPS

Austin Camp Mabry 77 92 78 95 / 20 20 0 0 Austin Bergstrom Intl Airport 77 92 79 94 / 20 20 0 0 New Braunfels Muni Airport 75 91 77 93 / 20 30 0 0 Burnet Muni Airport 75 91 77 92 / 20 10 0 0 Del Rio Intl Airport 76 96 78 99 / 10 10 0 0 Georgetown Muni Airport 76 91 78 94 / 20 10 0 0 Hondo Muni Airport 75 91 77 93 / 30 30 10 0 San Marcos Muni Airport 76 91 77 93 / 20 20 0 0 La Grange - Fayette Regional 77 92 79 95 / 20 30 0 0 San Antonio Intl Airport 76 91 78 93 / 30 30 10 0 Stinson Muni Airport 76 91 77 93 / 30 20 0 0

EWX WATCHES/WARNINGS/ADVISORIES

None.