Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX
Issued by NWS Austin/San Antonio, TX
579 FXUS64 KEWX 280608 AFDEWX Area Forecast Discussion National Weather Service Austin/San Antonio TX 108 AM CDT Thu Aug 28 2025 .KEY MESSAGES... - Hot conditions through the late work week into Saturday, then cooler than average conditions Sunday and for the start of next week - Rain chances returning Friday across the northern Hill Country and Austin metro, spreading southward Saturday, and peaking Sunday into Monday. - Main storm threats Friday through Monday are gusty winds in stronger storms and a Level 1 of 4 risk for excessive rainfall that could lead to isolated instances of flash flooding && .SHORT TERM (THROUGH FRIDAY)... A benign and generally rain free weather pattern will be in place through Friday morning as the region of higher moisture levels will shift northeastward towards the Texarkana region while mid-level ridging with 592-594 dam heights remains over South-Central Texas. Anticipate a hot end to the work week as afternoon highs both today and Friday top out from the mid to upper 90s into the 100 to 102 degree range across our hottest locations. Peak heat indices could climb into the 103 to 108 range across some areas, especially on Friday afternoon when dew points could be a tad bit higher. The mid-level ridge pattern does reposition slightly through Friday to the northwest. This slight reconfiguration is enough to allow a front to slide southward towards and into Central Texas. While some uncertainty remains on the front`s placement into Friday evening, majority of the guidance indicates that it should slow down and stall close to or just to the north of the Llano, Burnet, and Williamson subset of counties. With that said, We`ll feature low to medium (20-40%) rain and storm chances from Friday afternoon into Friday evening for areas to the north of the I-10 corridor with outflow propagation from initial convective activity farther to the north along the front. Given the instability with the hot afternoon temperatures, storms could be favorable of producing locally heavy downpours along with gusty winds that reach or exceed 40 mph. The WPC highlights a level 1 of 4 risk for excessive rainfall across portions of Llano, Burnet, Williamson, and Lee counties where rain may be quick and heavy enough for isolated instances of flooding Friday into Friday night. && .LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY)... An unsettled weather pattern is expected this weekend and for the start of next week thanks to the influence from the front. As mentioned from the day shift discussion yesterday, confidence with the southward progression of these earlier season fronts are often low, and the models seemed to have slowed any southward progress with the front from Friday night through Saturday. Latest model blends have adjusted the afternoon highs upwards on Saturday afternoon across the region as a result. Highs in the mid to upper 90s look to be common with some locations to the century mark for areas south and west of San Antonio. With more diurnal heating and increased lift from the nearby front, scattered convection will develop Saturday across the region. Propagating outflows could help to generate additional storms and gusty winds as well. Greatest concentration of activity focuses along and north of the I-10/I-37 corridor. Localized heavier downpours that could produce a quick couple of inches again will help to prompt a level 1 of 4 risk for excessive rainfall across the northern 2/3rds of the region for possible isolated instances of flooding. Models continue to indicate that a disturbance aloft within the northwest flow moving from West Texas into North-Central Texas from Saturday night into early Sunday helps to push the stalled front farther southward into and mostly through our south-central Texas region on Sunday. This will help to maximize our rain and storm chances to the 40 to 70% range on Sunday. The highest chances are expected to focus across the Southern Edwards Plateau and Hill Country. Rain chances will continue into Monday but expect for the highest chances to move into the western half of the region. WPC continues to highlight the entire region on Sunday and introduced the western 2/3rds of the region on Monday within a level 1 of 4 risk for excessive rainfall where isolated flash flooding may be possible. Overall, the latest ensemble means and deterministic medium range guidance, are indicating amounts on average across the region from Friday through Monday between a half inch and two inches, where highest amounts focus from the Hill Country into the Southern Edwards Plateau. As always, there will be some pockets with both higher and lower amounts but these locations may become easier to pinpoint as short term guidance becomes into view for this time period. A cooler than average temperature forecast is expected for Sunday into early next week with the modest post-frontal northeasterly flow. This will allow for highs in the 80s and morning lows in the 60s across the Hill Country. Elsewhere, highs in the low 90s and morning lows in the low 70s look to trend more common. The area temperatures look to warm back to around seasonal average by Wednesday. Low (10-30%) rain and storm chances linger Tuesday and Wednesday as well, but the highest chances are looking to favor towards the Rio Grande. While there is very high uncertainty with disagreements in the longer range guidance, there may be another front that possibly enters the state sometime late next week. && .AVIATION (06Z THURSDAY THROUGH FRIDAY)... VFR cigs are forecast across the local airports to about 08Z Thurs. Then, cigs begin to lower to MVFR at KSAT around 09Z, KSSF 10Z, KDRT 11Z, and KAUS 12Z. MVFR cigs could linger for a two to four hour period, before lifting to VFR. A light to moderate wind flow of 5 to 10 knots from the south is forecast for the I-35 terminals through the period while an east- southeast flow of 7 to 11 knots with gusts up to 18 knots (mainly in the afternoon hours) is forecast for KDRT. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 78 99 76 96 / 0 20 20 50 Austin Bergstrom Intl Airport 77 99 75 96 / 0 20 20 50 New Braunfels Muni Airport 76 100 75 98 / 0 10 10 40 Burnet Muni Airport 75 96 73 92 / 0 30 20 50 Del Rio Intl Airport 79 102 79 102 / 0 0 10 20 Georgetown Muni Airport 77 98 75 94 / 0 30 30 50 Hondo Muni Airport 75 100 75 99 / 0 0 10 30 San Marcos Muni Airport 75 99 74 98 / 0 20 10 40 La Grange - Fayette Regional 76 99 75 96 / 0 20 20 50 San Antonio Intl Airport 77 100 77 98 / 0 10 10 30 Stinson Muni Airport 78 101 78 100 / 0 0 10 30 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Short-Term...62 Long-Term...62 Aviation...17