Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX
Issued by NWS Austin/San Antonio, TX
989 FXUS64 KEWX 201129 AAA AFDEWX Area Forecast Discussion...UPDATED National Weather Service Austin/San Antonio TX 529 AM CST Thu Nov 20 2025 ...New AVIATION... .KEY MESSAGES... - Flood Watch is now in effect for parts of the Rio Grande, Southern Edwards Plateau, Hill Country, and I-35 Corridor through Friday morning due to the potential for heavy rain and localized flooding. - Some strong to isolated severe thunderstorms also possible overnight through Thursday morning, mainly west of the I-35 corridor - A line of strong to severe storms is forecast to develop across the Hill Country and I-35 Corridor Thursday afternoon into the evening associated with a dry line/surface trough - Another round of heavy rain is possible Sunday afternoon into Monday afternoon. There is some uncertainty for this round. However, medium range and ensemble models suggest the Southern Edwards Plateau, Hill Country, and I-35 Corridor to be impacted the most. && .SHORT TERM... (Today through Friday) Issued at 1213 AM CST Thu Nov 20 2025 The heavy rain event is under way as we go through the overnight period into Thursday morning. Ahead of a dry line/surface trough and mid to upper level pulses of energy, there is a developing low level jet spreading increased moisture across the Rio Grande and Southern Edwards Plateau. As a matter of fact, the 00Z Thu DRT sounding precipitable water (pwats) value was recorded at 1.72 inches which is way above the daily max value of 1.46 inches. The latest RAP sounding data shows pwats going up overnight to 1.82 inches over the Rio Grande and Southern Edwards Plateau. In addition, the sounding data suggests for instability to increase for the potential of strong to severe storms capable of producing large hail and strong wind gusts. Elevated shear values and hodograph presentation suggest that an isolated tornado can`t be ruled out. As the overnight goes on and the Thursday morning period arrives, hires models suggest for training cells over and over the Rio Grande, Southern Edwards Plateau, and western Hill Country. As above mentioned in the key messages, a Flood Watch is in effect mainly for areas along and west of Interstate 35 through Friday morning. Forecast storm rainfall totals range from 1 to 3 inches with isolated amounts of 6 to 8 inches across the watch area. Outside of the watch area, rainfall amounts are generally between 0.25 to 1.5 inches. The Weather Prediction Center highlights parts of the Rio Grande including Del Rio and areas to the northeast into the Edwards county including the cities of Rocksprings and Barksdale under a moderate risk of Excessive Rainfall. It is rare to see this in our area per local records. Therefore, we urge people to stay weather aware and to keep checking for weather updates from us and trusted resources. As the day progresses, an upper level short wave trough is forecast to push across the Four Corners region and into the Southern Plains by this evening. This scenario pushes a line of moderate to heavy rain and possible embedded strong to severe storms capable of producing large hail and strong winds. With elevated pwats, we are expecting pockets of heavy rain that are likely to affect the Hill Country and I-35 Corridor mid to late afternoon through the evening. There could be a lull of activity late this evening going into the overnight hours before a new line of showers and storms pushes across most of South Central Texas as a cold front moves through the region. Dry weather conditions are in store from northwest to southeast mid to late Friday morning into the afternoon hours. A cooler airmass spreads across South Central Texas with Friday`s highs in the lower to mid 70s across the Southern Edwards Plateau and Hill Country to lower 80s elsewhere. Very limited shower activity is forecast for Friday night into Saturday morning with overnight lows in the 50s over higher elevations and 60s across the rest of the local area. && .LONG TERM... (Friday night through Wednesday) Issued at 1213 AM CST Thu Nov 20 2025 Rain chances return across the Coastal Plains and parts of the Rio Grande on Saturday afternoon and evening as a warm front pushes northward into Highway 90. The warm front continues to push to the north and into the Hill Country overnight through Sunday morning. In the meantime, an elongated upper level short wave trough pushes across the Southern Plains including the local area. At the surface, a Pacific frontal boundary is forecast to push across South Central Texas between Sunday afternoon and Monday afternoon. Ahead of the boundary, models suggest for pwats to increase above normal values, which could result in another heavy rain event and localized flooding. With the potential of several inches of rainfall and isolated 6 to 8 inches during the tonight into Thursday night event, new rainfall amounts greater than couple of inches could be problematic for some areas of South Central Texas especially portions of the Southern Edwards Plateau, Hill Country, and the I-35 Corridor. Models are in better agreement of the occurrence of this second round, however, more details to come during future weather packages as there is still some uncertainly on timing and location. && .AVIATION... (12Z TAFS) Issued at 526 AM CST Thu Nov 20 2025 The forecast on the aviation side of things remains quite tricky as ironing out timing at AUS, SAT, and SSF will be the biggest challenge with afternoon/evening TSRA/SHRA. For now, have opted to mostly stick with what was inherited but to move the timeline forward and shrink the length of prevailing TSRA at the 3 sites. Otherwise, a very similar forecast from the previous with showers and thunderstorms this morning at DRT, transitioning east to the I-35 Corridor by late this afternoon into the evening hours. A secondary round may form after midnight, but significant uncertainty exists. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 81 66 81 61 / 50 70 50 20 Austin Bergstrom Intl Airport 83 66 80 61 / 40 60 60 30 New Braunfels Muni Airport 82 66 81 62 / 50 50 50 30 Burnet Muni Airport 76 63 77 55 / 60 80 40 10 Del Rio Intl Airport 76 61 80 58 / 90 20 10 10 Georgetown Muni Airport 80 64 80 58 / 60 80 50 20 Hondo Muni Airport 81 64 80 62 / 50 50 40 30 San Marcos Muni Airport 83 66 82 62 / 40 60 50 30 La Grange - Fayette Regional 84 68 83 63 / 20 30 60 40 San Antonio Intl Airport 82 68 80 65 / 40 50 50 30 Stinson Muni Airport 84 69 82 66 / 40 50 40 30 && .EWX WATCHES/WARNINGS/ADVISORIES... Flood Watch through late tonight for TXZ171>173-183>192-202>206- 217. && $$ SHORT TERM...17 LONG TERM....17 AVIATION...MMM