textproduct: Austin/San Antonio

KEY MESSAGES

Updated at 633 PM CDT Wed Sep 30 2026

- A Flood Watch is in effect from this evening through Friday evening for most of South Central Texas.

- Some storms tonight and Thursday may also be strong to severe.

- Low to medium rain chances linger through the weekend then decrease heading into next week.

SHORT TERM

(Tonight through Friday) Issued at 1258 PM CDT Wed Sep 30 2026

Upper air analysis this morning shows a 500mb low over the AZ/NM border producing southwesterly flow over TX. At the surface there is a low pressure center near the northwest TX/northeast NM border with a Pacific front extending from it. Over our CWA the flow is from the southeast keeping our warm, moist airmass in place. This morning's soundings at DRT and FWD show PW above 2 inches which is in the 90th percentile of the climatological record. The combined upper low will progress toward the northeast pushing the front into the northwestern part of our CWA tonight. This will be the beginning of a wet period. With the high PW air, showers and thunderstorms will be able to produce locally heavy rain. High resolution models are showing a line of thunderstorms moving across our CWA from the northwest to the southeast. In addition to locally heavy rain some storms could be severe producing damaging wind gusts and large hail with a tornado also possible. A Flood Watch remains in effect for all of South Central Texas except the eastern and southeastern edge counties. The watch is in effect from this evening until Friday evening. We expect widespread rainfall totals of 1-4 inches with isolated amounts up to eight inches. The higher rainfall totals will lead to flash flooding. The front will exit our CWA Friday morning and stall along the coast.

LONG TERM

(Friday night through next Wednesday) Issued at 1258 PM CDT Wed Sep 30 2026

With the front stalled across Deep South Texas, there will be continuing chances for rain into the weekend. The excessive PW values will have moved out of our CWA and rainfall totals will be more moderate. A few showers may linger into Monday. By Tuesday the front will have moved away and upper level ridging will move back over Texas bringing dry weather back. With cloudy skies and scattered showers the long term period will start off cooler with highs in the 70s and 80s Saturday. From there temperatures will slowly increase reaching the low to mid 80s by Tuesday.

AVIATION

(00Z TAFS) Issued at 633 PM CDT Wed Sep 30 2026

Quite the tricky aviation forecast for this package as the main concerns remain the convection from a line of storms approaching from the Hill Country overnight and MVFR timing for all TAF sites. For KAUS have extended the PROB30s for the next few hours due to recent radar trends. Otherwise the previous aviation forecast remains on track for the I-35 sites with main windows of convection likely from the early morning hours into the afternoon with a bit of a lull and then some more redevelopment towards the end of the TAF period. Confidence is higher for the first wave with prevailing TSRA. VCSH and -SHRAs are noted during the lull as could still see lighter activity with VCSH continuing throughout the forecast. Additionally, MVFR CIGs expected to develop by 05/06Z overnight and continue along with visibilities being reduced from the convection over the terminals. VFR CIGs should return by the end of the forecast period though wouldn't be surprised if MVFR CIGs linger longer. Winds may temporarily increase with variable flow during any rain and storm activity as well. Otherwise, outside of any convective influences, S/SE winds of 10 to 15 kts with higher gusts can be expected. For KDRT expect convective activity much earlier with PROB30 for 02 to 07Z with TSRA prevailing noted by 07Z and continuing into sunrise tomorrow. MVFR CIGs also look likely during this timeframe before activity moves off to the south and east and VFR CIGs return in by the afternoon hours.

PRELIMINARY POINT TEMPS/POPS

Austin Camp Mabry 76 91 73 82 / 70 90 90 90 Austin Bergstrom Intl Airport 76 91 72 82 / 60 90 90 90 New Braunfels Muni Airport 75 91 72 81 / 50 90 90 90 Burnet Muni Airport 73 83 70 79 / 80 90 70 90 Del Rio Intl Airport 73 90 70 85 / 90 50 30 50 Georgetown Muni Airport 75 88 72 81 / 70 90 90 90 Hondo Muni Airport 74 85 71 81 / 60 90 80 70 San Marcos Muni Airport 75 92 71 82 / 50 90 90 90 La Grange - Fayette Regional 76 94 73 85 / 40 90 90 90 San Antonio Intl Airport 77 88 73 81 / 50 80 90 90 Stinson Muni Airport 77 90 73 82 / 40 90 90 90

EWX WATCHES/WARNINGS/ADVISORIES

Flood Watch through Friday evening for TXZ171>173-183>193- 202>208-217>221-223-228.