Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX
Issued by NWS Austin/San Antonio, TX
441 FXUS64 KEWX 031117 AFDEWX Area Forecast Discussion National Weather Service Austin/San Antonio TX 617 AM CDT Wed Sep 3 2025 .KEY MESSAGES... - Warm and dry weather continues through the work week. - Rain chances return this weekend and early next week with some potential for locally heavy rain. Continue to monitor the forecast. && .SHORT TERM (THROUGH THURSDAY)... Quiet weather across South Central Texas will continue through midweek as dry mid-level air continues to funnel in from the north from the Great Plains. The 00Z soundings across Texas this past evening indicated relative humidity values aloft of 3 to 10 percent in the mid-troposphere within that band of dry northerly flow, and this is helping to maintain those quiet conditions. Expect mostly clear and dry weather Wednesday with highs in the mid 90s in the Hill Country and upper 90s to near 100 for the Rio Grande, I-35 corridor, and Coastal Plains. Like Tuesday, a small and brief lone shower or two could crop up over the Coastal Plains in the late afternoon with daytime heating, but without much fanfare. The mid-level ridge over New Mexico responsible for the dry northerly wind starts to slide more over our area Wednesday night into Thursday. The calm weather combined with lower dew points will make for a relatively cooler Thursday morning with lows in the 60s north of I-10. That same ridge is paired with a thermal ridge that will also support a large temperature swing during the day, so Thursday will likely be the warmest day of the week with a triple digit dry heat prevailing for most of South Central Texas that afternoon under clear skies. Current forecast highs for Thursday are generally between about 97 to 102 degrees throughout the region. && .LONG TERM (THURSDAY NIGHT THROUGH TUESDAY)... The mid-level ridge Thursday continues its eastward drift into Friday, but enough of the ridge will still be around to give South Central Texas another warm day with highs in the upper 90s with pockets of 100-degree highs. After Friday, the ridge starts to break down as a shortwave trough subtly amplifies over the Desert Southwest and moves across Texas this weekend into early next week. This trough is expected to draw a plume of Eastern Pacific moisture from Tropical Storm Lorena, which is forecast to be near the Baja California Peninsula on Friday with its vorticity and moisture being sheared away. As this energy and moisture is ingested into and ahead of the trough and spreads across Texas, rain chances increase over our region with the highest odds on Sunday and Monday based on the current timing of the modeled disturbances. There is good consensus across the medium-range ensemble guidance that moisture levels over our area will be on the rise this weekend as moisture arriving from TS Lorena or its remnants overlaps with an uptick in moisture arriving from the Gulf, with combined outputs from the GEFS, ENS, and GEPS ensemble suites indicating PWATs likely reaching at least 1.8 to 2.1 inches over South Central Texas. This indicates that the environment over our region could support heavy rainfall this weekend into early next week. However, there is still considerable uncertainty over the location and intensity of those rains largely due to discrepancies with how the models are handling the remnants of TS Lorena. The GFS has consistently been one of the more aggressive models, keeping the energy associated with the tropical system intact and combining it with the trough to produce a more potent low pressure system over Texas, resulting in more aggressive rainfall projections. The ECMWF and CMC deterministic outputs have so far stayed the course with a less aggressive approach, one that features a weaker trough with some broader and ill-defined reconstituted components of TS Lorena`s remnant vorticity as opposed to a direct phasing of the two disturbances. Consequently, the rainfall outputs from those models are lower. The wide uncertainty displayed in the global synoptic models is also reflected in the regional hurricane models which show a wide range of outcomes regarding the evolution of what`s left of TS Lorena. While it`s too early to talk about specific rainfall amounts, the moist air and increased rain chances warrant closely monitoring trends for this weekend and early next week. This active weather period may start to wind down Tuesday as drier continental air begins to work its way behind the outgoing trough. && .AVIATION (11Z WEDNESDAY THROUGH THURSDAY)... VFR conditions are forecast through the TAF period, with a mix a thin, high cirrus and FEW-SCT afternoon cumulus field. Variable winds less than 5 KT this morning, becoming NW to N 5-8 KT this afternoon and early evening. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 70 101 75 100 / 0 0 0 0 Austin Bergstrom Intl Airport 68 101 74 100 / 0 0 0 0 New Braunfels Muni Airport 69 101 73 99 / 0 0 0 0 Burnet Muni Airport 66 97 72 96 / 0 0 0 0 Del Rio Intl Airport 73 101 76 100 / 0 0 0 0 Georgetown Muni Airport 67 100 73 99 / 0 0 0 0 Hondo Muni Airport 69 101 72 99 / 0 0 0 0 San Marcos Muni Airport 68 102 71 101 / 0 0 0 0 La Grange - Fayette Regional 69 99 73 98 / 0 0 0 0 San Antonio Intl Airport 72 101 74 99 / 0 0 0 0 Stinson Muni Airport 73 102 75 101 / 0 0 0 0 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Tran LONG TERM...Tran AVIATION...76