On September 8th, a slow moving surface front entered a very moist environment where precipitable water values were near and above two inches. Thunderstorms developed and some produced heavy rain that led to flash flooding.
Every event with a place to put it. Tap one for its entry below.
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.
On September 8th, a slow moving surface front entered a very moist environment where precipitable water values were near and above two inches. Thunderstorms developed and some produced heavy rain that led to flash flooding. The pattern remained unchanged on the 9th and thunderstorms with heavy rain developed again, but the focus was generally farther east.
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 Sep 8, 6:05 AM CST, 1 hour 25 minutes earlier.
Area Forecast Discussion National Weather Service Austin/San Antonio TX 705 AM CDT Sat Sep 8 2018 .UPDATE... Please see the 12Z aviation forecast discussion below. && .AVIATION... Convection has temporarily weakened along the I-35 corridor this morning and we will only mention VCSH along with MVFR cigs. Out west at DRT, convection is more widespread and have opted to go with prevailing -SHRA and TEMPO groups for TSRA this morning. There will be a very good chance for continued shower and thunderstorm development this afternoon and evening with daytime heating and a slow moving cold front. && .PREV DISCUSSION... /ISSUED 450 AM CDT Sat Sep 8 2018/ ..Locally Heavy Rain and Flash Flooding Possible... SHORT TERM (Today through Sunday)... Widespread rain is expected today through Sunday especially along and west of Interstate 35. A Flash Flood Watch is now in effect for areas along and west of I-35 through Sunday morning. Rich tropical moisture coupled with a slow moving frontal boundary will lead to localized heavy rain today through Sunday. Scattered to numerous showers and thunderstorms are expected ahead of the actual frontal boundary for most of the today period. Later this afternoon and evening, the frontal boundary is forecast to push across the Rio Grande Plains. An upper level disturbance across the Southern Plains will also serve to enhance shower and thunderstorm development late tonight into Sunday. Storm total amounts of 1 to 3 inches are possible with isolated amounts up to 7 inches. The heavy rains should become more isolated Sunday afternoon, allowing the flash flood concerns to decrease. LONG TERM (Sunday Night through Friday)... The upper level disturbance moves to the southeast Sunday evening while an upper level ridge builds into our area from the west. This will allow for showers and thunderstorms to decrease or come to an end from the northwest to southeast parts of South Central Texas. Some HiRes and medium-range models suggest for the frontal boundary to stall across the Coastal Plains Sunday evening into Monday for chances of rain over that area. Several upper level short-waves are expected to move across South Central Texas for the first part of next week to keep rain chances over parts of the southeast and Coastal Plains. An inverted upper level trough is forecast to move across the southern coastal states into our area later in the week for rain chance mainly across the eastern half of South Central Texas. Temperatures will be cooler and slightly below climate normal values through the period due to cloud coverage and wet soils. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 89 73 84 71 86 / 70 60 50 20 20 Austin Bergstrom Intl Airport 90 73 83 70 87 / 70 60 50 30 20 New Braunfels Muni Airport 90 72 84 70 87 / 70 70 60 30 30 Burnet Muni Airport 84 70 82 68 84 / 80 50 40 10 10 Del Rio Intl Airport 81 71 82 69 84 / 80 50 50 10 10 Georgetown Muni Airport 88 71 84 68 86 / 70 50 30 20 10 Hondo Muni Airport 87 72 83 70 85 / 60 70 70 40 10 San Marcos Muni Airport 90 72 83 70 86 / 70 70 60 30 20 La Grange - Fayette Regional 92 73 85 72 87 / 50 50 50 40 50 San Antonio Intl Airport 89 73 82 70 85 / 70 70 60 40 20 Stinson Muni Airport 90 74 83 71 85 / 60 70 70 40 30 && .EWX WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch through Sunday morning for Bandera-Bexar-Blanco- Burnet-Comal-Dimmit-Edwards-Frio-Gillespie-Hays-Kendall-Kerr-Kinney- Llano-Maverick-Medina-Real-Travis-Uvalde-Val Verde-Williamson- Zavala. && Mesoscale/Aviation...Platt Synoptic/Grids...17
Hazardous Weather Outlook National Weather Service Austin/San Antonio TX 526 AM CDT Sat Sep 8 2018 TXZ171>173-183>194-202>209-217>225-228-091030- 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- 526 AM CDT Sat Sep 8 2018 This Hazardous Weather Outlook is for South-Central Texas.. .DAY ONE...Today And Tonight. Scattered to numerous showers and thunderstorms are expected across South Central Texas today and tonight. The main concern will be heavy rainfall and possible flooding. A Flash Flood Watch is in effect for areas along and west of the Interstate 35 corridor. Areas that have recently seen heavy rainfall will be at greater risk for flash flooding. .DAYS TWO THROUGH SEVEN...Sunday through Friday. Scattered to numerous showers and thunderstorms will continue across South Central Texas through Sunday. Isolated areas of heavy rainfall could lead to flooding mainly across areas that have had significant rains recently. A Flash Flood Watch will be in effect for areas along and west of the Interstate 35 corridor until mid-morning Sunday. Showers and thunderstorms will gradually become less numerous Monday through Wednesday. Locally heavy rains may cause some minor flooding. .SPOTTER INFORMATION STATEMENT... While spotter activation is not anticipated, any reports of heavy rainfall or flooding are appreciated.
The Laughlin AFB radar (KDFX), 39 km away, was scanning. The volume nearest the first event began at 13:32 UTC.
11 flash flood. Local standard time, as filed.
Thunderstorms produced heavy rain that led to flash flooding of the Nueces River. The river flooded Hwy 55 near Montell.
Thunderstorms produced heavy rain that led to flash flooding. Multiple low water crossings on River Rd. were flooded by the Frio River near Concan.
Thunderstorms produced heavy rain that led to flash flooding closing multiple roads around Uvalde including Hwy 55.
Thunderstorms produced heavy rain that led to flash flooding closing 43 roads across the city of San Antonio.
Thunderstorms produced heavy rain that led to flash flooding sending Rocky Creek over Old Castroville Rd. near the northern end of Medina Lake.
Thunderstorms produced heavy rain that led to flash flooding. Bandera Creek Rd. was washed out at West Verde Creek in the Hill Country State Natural Area.
Thunderstorms produced heavy rain that led to flash flooding. Hondo Creek flooded FM 462 north of Hondo. FM 463 was also flooded at Twin Hollow Creek.
Thunderstorms produced heavy rain that led to flash flooding. Lehman Rd. south was flooded at Masonwood Dr. in Kyle.
Thunderstorms produced heavy rain that led to flash flooding. The Blanco River flooded Wayside Dr. southwest of Wimberley.
Thunderstorms produced heavy rain that led to flash flooding. The low water crossing near Helotes Creek at FM 1560 and Parrigin Rd. in Helotes was flooded up to the three foot marker.
Thunderstorms produced heavy rain that led to flash flooding. Privilege Creek flooded Privilege Creek Rd. sending nine inches of water over the road northwest of Pipe Creek.
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, September 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: 783940, 783941, 783942, 783943, 783944, 784065, 784074, 784075, 784076, 784079, 784144.