Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX
Issued by NWS Austin/San Antonio, TX
162 FXUS64 KEWX 301135 AFDEWX Area Forecast Discussion National Weather Service Austin/San Antonio TX 635 AM CDT Sat Aug 30 2025 .KEY MESSAGES... - Rain chances spreading south today to include San Antonio, then all areas Sunday into Monday. - Locally heavy rains possible today through Monday. The main threat is urban and small stream flooding with a marginal to slight risk of flash flooding. - Above average temperatures today, turning below average on Sunday into Monday, then near average remainder of the week. && .SHORT TERM (THROUGH MONDAY NIGHT)... A cold front gradually drifts across South Central Texas due to a northerly flow aloft this weekend into Monday. Moisture convergence along the frontal zone will increase PWs to around 2+ inches which is around 150 percent of late August/early September averages. Forcing by the frontal zone, heating, and possibly a couple of weak mid level impulses will generate showers and thunderstorms over the Edwards Plateau, Hill Country to along and east of the I-35 corridor as far south as the San Antonio area today, then all areas on Sunday into Monday. Efficient rainfall processes along with rather slow or repeat storm motions will bring locally heavy rains with possible amounts of 3 to 5 inches and create a threat of flooding. WPC has marginal to slight risks (levels 1 to 2 of 4) for excessive rains leading to flash flooding. The main threat is urban and small stream type flooding. However, should the heavy rains fall over areas with earlier heavy rains, then the threat for flash flooding increases. We will monitor trends for a possible flood watch issuance. Due to moist and unstable airmass, wind gusts up to around 40 mph are possible with the strongest storms. The hot, above late August average temperatures continue today most areas as the showers and thunderstorms hold off until peak heating. With increasing moisture, dewpoints will not mix as efficiently keeping afternoon heat indices a little more elevated possibly briefly reaching heat advisory levels of around 108. With the increasing clouds and rain areas, as well as weak cold advection, temperatures will fall to well below late August/early September averages across the Hill Country to areas north and east of San Antonio on Sunday, then all areas on Monday. && .LONG TERM (TUESDAY THROUGH FRIDAY)... A northerly flow at the surface and aloft dries the airmass. Rains taper off on Tuesday, followed by little or no rain on Wednesday and Thursday. Slight rain chances may return on Friday over the Edwards Plateau due to possibly a mid level impulse or another front. Temperatures remain near early September averages. && .AVIATION (12Z SATURDAY THROUGH SUNDAY)... Low cigs/MVFR category are ongoing and affecting the I-35 airports for a couple of hours. By 15Z or shortly after, VFR conditions should dominate across the local area. Then later in the afternoon, MVFR cigs are anticipated for KAUS as showers and storms develop across the Hill Country and move to the south. This activity is expected to hold and makes it to the San Antonio area by 00Z Sunday for MVFR cigs. Low confidence on this activity making it to KSSF and decided to add -SHRA but keeping things at VFR. For KDRT, VFR conditions persist through the forecast package. Southeast to south winds are forecast to prevail across all terminals through the period with the exception of those times when showers and storms are moving overhead and the wind flow could shift. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 76 90 73 88 / 30 80 60 60 Austin Bergstrom Intl Airport 76 90 73 88 / 30 80 60 60 New Braunfels Muni Airport 75 95 72 90 / 20 60 60 60 Burnet Muni Airport 74 86 71 86 / 40 90 60 50 Del Rio Intl Airport 79 99 76 91 / 10 30 60 70 Georgetown Muni Airport 75 89 71 86 / 40 90 60 50 Hondo Muni Airport 75 97 72 90 / 10 40 50 70 San Marcos Muni Airport 75 94 72 89 / 20 70 60 60 La Grange - Fayette Regional 76 90 73 86 / 30 70 50 60 San Antonio Intl Airport 77 96 75 90 / 20 50 60 70 Stinson Muni Airport 78 98 77 91 / 20 50 50 70 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...04 LONG TERM...04 AVIATION...17