An upper level low over West Texas and stationary front combined to generate thunderstorms some of which produced heavy rain leading to flash flooding. 50 inches of rain.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS EWX wrote it up.
An upper level low over West Texas and stationary front combined to generate thunderstorms some of which produced heavy rain leading to flash flooding. An observer in Reagan Wells in Uvalde County reported 6.50 inches of rain.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Austin/San Antonio, TX wrote its last area forecast discussion before the first event at Aug 12, 5:38 AM CST, 1 hour 24 minutes earlier.
Area Forecast Discussion National Weather Service Austin/San Antonio TX 638 AM CDT Sun Aug 12 2018 .AVIATION... Ceilings have set in across South Central Texas with DRT being a mix of VFR/MVFR, AUS holding at MVFR, and the San Antonio terminals (SAT/SSF) currently at IFR. Improvement will be slow through them morning with SAT/SSF becoming MVFR by 15z and cigs at all terminals becoming VFR by mid-day around 18z. Winds will continue to be out of the southeast today across the area about 10 knots. AUS and DRT have already seen scattered showers this morning moving within the vicinity of the terminals while SAT remains dry. Coverage of showers and thunderstorm activity should increase through the day. Thunderstorms will also be possible during the afternoon hours prompting the change from VCSH to VCTS within the TAFs. Precipitation could last through the afternoon into the overnight hours before shifting westward late tonight into Monday morning. At this point have precipitation ending that I-35 terminals around 08z tonight with the return of MVFR cigs due to the plentiful moisture still over the area. && .PREV DISCUSSION... /ISSUED 337 AM CDT Sun Aug 12 2018/ SHORT TERM (Today through Monday)... Upper air analysis last evening showed a low over New Mexico with weak flow over Texas. A weak pressure gradient at the surface had winds light and variable. There were two frontal boundaries stalled across the region. One was across our CWA from northeast to southwest and the other was to the north of us. The upper low will drift slowly toward the northeast through this period. PW values from 00Z soundings were 1.85 inches at DRT and 2.05 inches at CRP. PW is forecast to remain near or above 2 inches over most of our CWA today. Convection is likely today with the upper low and stalled surface boundaries. The best chances for precipitation will be west of a line from Burnet to Hondo to Carrizo Springs. With the high PW, locally heavy rain is possible and a few places could see minor flooding especially places that have had rain over the last couple of days. Rainfall totals will be one to three inches with isolated spots of five inches. As the upper low moves away Monday, PW will decrease across the area. Rain chances will decrease from the southeast. The area of likely POPs will be confined to the western Edwards Plateau with only chance and slight chance south and east of there. LONG TERM (Monday Night through Saturday)... The upper low will open into a wave and accelerate to the northeast starting Monday night. This will continue a decrease in our rain chances. There will only be slight and low end chances POPs Monday night over the northern Hill Country and Edwards Plateau. The decreased PW will mean no heavy rain during this period. By Tuesday the subtropical ridge will begin building back into Texas from the Gulf bringing dry weather back to the region. The ridge will become stronger through the rest of the week suppressing convection. Temperatures will also warm through the week under sunny skies and subsidence. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 90 75 94 76 96 / 60 40 20 - - Austin Bergstrom Intl Airport 90 75 94 75 96 / 60 40 20 - - New Braunfels Muni Airport 90 75 94 75 95 / 60 50 20 - 10 Burnet Muni Airport 85 73 90 73 93 / 60 60 30 10 - Del Rio Intl Airport 85 73 89 76 94 / 80 80 60 30 10 Georgetown Muni Airport 88 74 92 75 96 / 60 50 30 - - Hondo Muni Airport 90 74 95 75 97 / 70 60 30 10 - San Marcos Muni Airport 90 75 93 75 96 / 60 40 20 - - La Grange - Fayette Regional 92 76 95 75 97 / 50 20 10 - 10 San Antonio Intl Airport 89 76 94 76 96 / 60 60 20 - - Stinson Muni Airport 91 77 95 76 96 / 60 50 20 - - && .EWX WATCHES/WARNINGS/ADVISORIES... None. && Mesoscale/Aviation...Treadway Synoptic/Grids...05
Hazardous Weather Outlook National Weather Service Austin/San Antonio TX 414 AM CDT Sun Aug 12 2018 TXZ171>173-183>194-202>209-217>225-228-130915- Llano-Burnet-Williamson-Val Verde-Edwards-Real-Kerr-Bandera- Gillespie-Kendall-Blanco-Hays-Travis-Bastrop-Lee-Kinney-Uvalde- Medina-Bexar-Comal-Guadalupe-Caldwell-Fayette-Maverick-Zavala- Frio-Atascosa-Wilson-Karnes-Gonzales-De Witt-Lavaca-Dimmit- 414 AM CDT Sun Aug 12 2018 This Hazardous Weather Outlook is for South-Central Texas.. .DAY ONE...Today And Tonight. Locally heavy rain is possible today through tonight across the Southern Edwards Plateau, Hill Country, and Rio Grande Plains. Rainfall totals of one to three inches are expected with isolated higher amounts possible. Pockets of localized flooding are possible, especially across areas that have seen rainfall Friday and Saturday. .DAYS TWO THROUGH SEVEN...Monday through Saturday. Locally heavy rainfall is possible on Monday across the northern Rio Grande Plains and Edwards Plateau. An additional half inch of rain is possible with precipitation on Monday. No hazardous weather is expected Tuesday through Saturday. .SPOTTER INFORMATION STATEMENT... Spotter activation is not anticipated.
Special Weather Statement National Weather Service Austin/San Antonio TX 617 AM CDT Sun Aug 12 2018 TXZ171>173-183>192-202>206-217-218-122100- Llano-Burnet-Williamson-Val Verde-Edwards-Real-Kerr-Bandera- Gillespie-Kendall-Blanco-Hays-Travis-Kinney-Uvalde-Medina-Bexar- Comal-Maverick-Zavala- Including the cities of Llano, Burnet, Georgetown, Del Rio, Rocksprings, Leakey, Kerrville, Bandera, Fredericksburg, Boerne, Blanco, San Marcos, Austin, Bracketville, Uvalde, Hondo, San Antonio, New Braunfels, Eagle Pass, and Crystal City 617 AM CDT Sun Aug 12 2018 ...LOCALLY HEAVY RAIN COULD LEAD TO ISOLATED FLASH FLOODING... Isolated flash flooding is possible today due to heavy rainfall. An upper level low will interact with a surface boundary to generate showers and thunderstorms today. Some of these storms will produce heavy rainfall. Rainfall totals will be one to three inches with a few places getting up to five inches. This rain could lead to flash flooding. Places that have received rain over the last few days will be more prone to flooding.
The Laughlin AFB radar (KDFX), 55 km away, was scanning. The volume nearest the first event began at 13:00 UTC.
5 flash flood. Local standard time, as filed.
Thunderstorms produced heavy rain that led to flash flooding near FM 1051 and US Hwy 83 along the Nueces River near Concan.
Thunderstorms produced heavy rain that led to flash flooding along Hwy 55 at the Nueces River and Indian Creek. Hwy 55 was closed between Uvalde and Camp Wood.
Thunderstorms produced heavy rain that led to flash flooding. Based on radar estimates, 8-11 inches of rain fell in a three hour period across northwestern Uvalde County. Many low water crossings flooded across this area, and Highway 55 was closed from Uvalde to Camp Wood. A flood wave traveled down the Nueces River and through the Chalk Bluff camp ground. Several people from the camp ground became stranded in trees and on roof tops of vehicles, and some were reported swept downstream. Twenty-seven people were successfully rescued from the flood waters by boats and helicopter. One person was treated for a head injury and two children were treated for hypothermia. Estimated monetary loss of one hundred thousand dollars based on flooded cars and trailers that were lost downstream.
Thunderstorms produced heavy rain that led to flash flooding closing several roads in southern San Antonio. Road closures were reported on the bexarflood.org website.
Thunderstorms produced heavy rain that led to flash flooding closing the low water crossing at Jungman Rd. and the Medina River outside of Lacoste.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Texas in 2018Every state in 2018This day in weather historyWarnings in Texas, August 2018
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 779462, 779464, 779465, 779467, 779469.