Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX
Issued by NWS Austin/San Antonio, TX
433 FXUS64 KEWX 111104 AFDEWX Area Forecast Discussion National Weather Service Austin/San Antonio TX 604 AM CDT Mon Aug 11 2025 ...New AVIATION... .KEY MESSAGES... - Slightly less stable conditions later in the week could signal a shift toward increasing rain chances. - Seasonably hot weather should continue with a near flat trend on high temperatures through the weekend. && .SHORT TERM... (Today through Tuesday) Issued at 1208 AM CDT Mon Aug 11 2025 An inverted upper trough initially aligned along the TX coast as a SW-NE axis drifts farther inland today and then gets pulled north to merge with a polar trough over OK/NW TX by Tuesday. Due to the influence of the polar trough, the position of the Gulf upper disturbance has more of the north pivot than was shown in earlier model solutions for today into Tuesday. This has resulted in a downward trend in PoPs for most of the area today and again for most areas for daytime Tuesday. The Edwards Plateau and Hill Country may see a boost in available moisture as residual mid level moisture from NW TX convection today will drift southeast in a weak NW flow aloft pattern over West Central TX by late in the day. Better rain chances here will probably be suited for mainly 21Z Tuesday to 03Z Wednesday. The two convergent disturbances from the SE and NW could lead to gradually increasing PWat values to perhaps add a few more daytime cumulus, but high temperatures should remain somewhat flat with most areas seeing mid 90 to lower 100s. && .LONG TERM... (Tuesday night through Sunday) Issued at 1208 AM CDT Mon Aug 11 2025 A few clustered areas of convection could take advantage of daytime heating and NW flow aloft over West Central TX and spread south into our southern Edwards Plateau and Hill Country counties Tuesday evening. Storm motion vectors are going to come to a stall as any convection reaches this area, so we are expecting mainly 20-30 percent type coverage, and cells that do not last particularly long. Even so, the time of year would suggest any type of storm clustering if even brief could lead to an isolated pocket of heavy rainfall that could exceed one inch. Since the NW flow aloft at the base of the polar trough is only at the upper levels and not the mid levels, we should see the better rain chances holding to the north, but perhaps shifting slightly east toward Central TX to follow the PVA of the polar trough. While this does not bring rain to most areas, it doesn`t allow for the ridge to fill back in either. There will be a weak shear axis that could support convection around any weak disturbance that might crop up in the region. One such feature is a mid to upper level disturbance that looks the part of a tropical wave but does not appear to show such features at lower levels of the atmosphere. The GFS has been picking up on this feature moving over the Yucatan Wednesday and toward TX by late Friday, with the subtle feature noticeable since at least the 08/10/00Z cycle. The ECM sees this feature as well, but has been more conservative in keeping it on a westward track into Mexico. The GFS also sends mainly toward Mexico, but closer to BRO and curves it north across our EWX counties late Friday into early Saturday. In an otherwise mostly stable air regime, the vorticity with this system might be enough to generate at least some elevated PWat values and diurnal activity Friday evening and midday Saturday before the feature weakens and gets absorbed into a broader weakness over N TX and OK. For now we will introduce a slight chance of convection for this period as moisture availability and tracking of this system will probably still be a bit tricky. Going deeper into the weekend, the pattern remains weakly stable, with a westward moving H5 ridge moving west to suggest a hotter and more stable pattern for early next week. && .AVIATION... (12Z TAFS) Issued at 601 AM CDT Mon Aug 11 2025 Patchy MVFR ceilings have formed near SAT/SSF this morning and may last a few more hours before returning to VFR. Otherwise, VFR conditions are expected the rest of the period. Winds remain east- southeasterly to southerly with speeds generally around 10 kts or less. There is a very low chance for an isolated shower or thunderstorm later this afternoon around I-35 sites, but will keep this mention out of the TAF due to low confidence. KDRT will see mostly clear skies and dry conditions. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 97 76 97 76 / 10 10 20 10 Austin Bergstrom Intl Airport 97 76 97 76 / 10 10 20 10 New Braunfels Muni Airport 97 74 97 74 / 10 10 10 10 Burnet Muni Airport 94 74 93 74 / 0 0 20 10 Del Rio Intl Airport 100 79 100 78 / 0 0 10 10 Georgetown Muni Airport 97 75 96 76 / 10 10 20 10 Hondo Muni Airport 98 74 98 74 / 0 0 10 10 San Marcos Muni Airport 97 74 98 74 / 10 10 10 10 La Grange - Fayette Regional 95 75 95 75 / 10 10 20 10 San Antonio Intl Airport 98 76 97 76 / 10 10 10 10 Stinson Muni Airport 99 76 100 76 / 10 10 10 10 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Short-Term...18 Long-Term...18 Aviation...27