Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX
Issued by NWS Austin/San Antonio, TX
721 FXUS64 KEWX 221909 AFDEWX Area Forecast Discussion National Weather Service Austin/San Antonio TX 209 PM CDT Fri Aug 22 2025 .KEY MESSAGES... - Isolated to scattered convection persists through the weekend with locally heavy rainfall and gusty winds near the stronger storms. - A cold front brings slightly cooler temperatures and an uptick in rain chances on Wednesday. && .SHORT TERM (THROUGH SATURDAY NIGHT)... A mid and upper level shear axis combined with plenty of moisture and residual outflow boundaries have combined with daytime heating to help generate some convection across portions of south central Texas this afternoon. Any additional outflow boundaries from the area of convection ongoing north of Houston should aid in additional development, mainly east of I-35 this afternoon and evening. Farther west, we should see at least some isolated convection across the Hill Country, southern Edwards Plateau and Rio Grande plains and we have updated the forecast to add mention of this. Similar to the last few days, localized heavy rainfall and gusty winds can be expected with the stronger storms. While most of the convection will be tied closely to daytime heating, would not be surprised to see some late evening and overnight convection near the coastal plains as a fair amount of the models do show some convection in the mentioned area. A fairly similar weather pattern is anticipated on Saturday as the mid and upper level shear axis begins to slide southward in response to the subtropical ridge building in from the northwest. As this occurs, the best chances for showers and storms will reside east of I-35/I-37 and into the coastal plains region. However, we will keep a 20% chance for convection as far west as the Hill Country and southern Edwards Plateau on Saturday. A few spots may pick up some locally heavy rainfall, with the coastal plains region likely being favored as moisture will be higher in this region. Temperatures through Saturday night should remain at or perhaps just below normal for this time of year. && .LONG TERM (SUNDAY THROUGH FRIDAY)... With the subtropical ridge axis continuing to strengthen across the region on Sunday, we will see rain chances continue to shift southward, with the coastal plains region being favored for isolated to scattered convection. The subtropical ridge axis persists into Monday, but with daytime heating and sufficient moisture, we should see some isolated convection, with perhaps a little better chance farther south near the coastal plains. Temperatures may nudge upward slightly on Sunday into Monday, but should remain very close to climatological normals. While the subtropical axis is expected to persist into the middle of next week, an upper trough axis moving through the eastern half of the country will aid in pushing a frontal boundary into the region sometime late Tuesday or early Wednesday. With a cold front in the region and sufficient moisture, we should see at least scattered convection on Wednesday and possible into Thursday. Temperatures should also ease a little behind the boundary during the mid-week period. A gradual weakening of the subtropical ridge appears to develop late next week as a mid and upper trough persists over the eastern half of the U.S. && .AVIATION (18Z FRIDAY THROUGH SUNDAY)... VFR conditions expected through the TAF period with exception of any convective activity. Latest guidance indicates isolated to scattered SHRA and TSRAs should initiate this afternoon with the best chances along and east of the I-35 Corridor. Currently seeing -SHRAs forming just to east of KAUS from an outflow boundary. Kept PROB30 groups between 19Z and 01Z for -TSRA at KAUS, KSAT, and KSSF. Could see wind gusts at or above 30 kts due to possible downdrafts with any -TSRAs that form over the TAF sites. Otherwise winds should remain light, below 10 kts with VRB wind direction. For KDRT expect VRB winds around 19Z and lasting until the overnight hours before turning easterly but remaining under 10kt. Based on observational trends for tomorrow, decided to add PROB30s for both KAUS and KSAT 19Z to 24Z for the afternoon as we could see -TSRAs forming once again. Otherwise VRB winds under 10kt are expected. For KDRT there is a chance of -TSRAs and VCSH for Saturday afternoon however, the chance is under 20% so have elected to keep out of this TAF forecast for now but will continue to monitor and amend at needed. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 74 95 74 97 / 10 30 10 10 Austin Bergstrom Intl Airport 73 94 72 96 / 20 30 10 10 New Braunfels Muni Airport 72 94 70 96 / 20 40 10 20 Burnet Muni Airport 72 92 71 94 / 10 10 0 10 Del Rio Intl Airport 76 94 74 97 / 20 20 10 20 Georgetown Muni Airport 72 94 71 97 / 10 20 0 10 Hondo Muni Airport 72 93 71 94 / 10 30 10 20 San Marcos Muni Airport 72 94 70 96 / 20 40 10 10 La Grange - Fayette Regional 72 92 72 94 / 30 50 10 20 San Antonio Intl Airport 75 94 75 96 / 20 40 20 20 Stinson Muni Airport 75 95 75 97 / 20 40 20 20 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Short-Term...Platt Long-Term...Platt Aviation...CJM