A cold front moved through South Central Texas and generated thunderstorms. Some of these storms produced large hail and heavy rain that led to flash flooding.
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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.
A cold front moved through South Central Texas and generated thunderstorms. Some of these storms produced large hail and heavy rain that led to flash flooding.
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 Apr 10, 6:23 PM CST, 4 hours 17 minutes earlier.
Area Forecast Discussion National Weather Service Austin/San Antonio TX 723 PM CDT Mon Apr 10 2017 .MESOSCALE UPDATE... Spent a good amount of time attempting to add some timing precision to the WX/PoP/QPF grids for the next 18 hours. While some initial CI has begun in the vicinity of San Antonio, capping continues to hold on preventing cells from growing upscale without help from a surface boundary...unlike the convection farther north. In regards to activity farther north, SPC mesoanalysis and proximity RAP soundings show the cap eroded along the boundary with surface dewpoints at or near 70 degrees and 3000+ J/KG to tap into. Convergence along the front is maximized from north of Kerrville and northeast whereas farther west, weaker low level flow and less favorable moisture flux vector orientation to the front has kept the majority of the plateau from convecting. CAM guidance continues to ramp up QPF values however some guidance, especially the HRRR, appears to be overconvecting in the next 2-4 hours. While these values are not being disregarded, the TTU-WRF model has been generally handling this convection thus far rather well. It continues to convect more along the favorable convergent zone along the front, becoming outflow dominant, and thus convecting farther southeast along the line beginning around 10PM. These new storms will be able to capitalize on the high instability and PWAT values of over 1.5" advecting into the I-35 corridor allowing for hourly rainfall rates of over 2 inches per hour possible. This means that the QPF forecasts of 2-4 inches with isolated up to 7 inches is still very much valid for all areas east of the Edwards escarpment as well as along and east of the I-35 corridor. Also, with the high instability and appreciable shear, quarter size hail and damaging winds are also still possible through 11PM. However, these threats are secondary to the flash flood threat, which is still the more significant impact for the next 12 hours. && .PREV DISCUSSION... /ISSUED 622 PM CDT Mon Apr 10 2017/ AVIATION DISCUSSION...FOR 00Z TAF PERIOD... Expecting TSRA development northwest of the KAUS terminal in the first 6 hours of the TAF period. Some isolated development has already been observed in the vicinity but have been short lived with sporadic ltng. Included TEMPO for possible iso storms for first 3 hours and then prevailing afterwards. Latest models have a line of TSRA to begin impacting around 03Z and an hour or so later for KSAT/KSSF. Hvy rain will be the primary impact to the terminals in addition to lightning thus reduced VIS as a result. CIGs will be difficult but should fluctuate around low end MVFR and IFR during storm impact. Activity is expected to be clear of all terminals by 10-12Z. However cloud cover is expected to prevail through much of the morning hours. Only marginal improvement to CIGs is expected by the afternoon hours tomorrow. PREV DISCUSSION... /ISSUED 332 PM CDT Mon Apr 10 2017/ SHORT TERM (Tonight through Tuesday Night)... .Dangerous Flash Flooding Event Possible Late This Afternoon through Tonight across South Central Texas... Complex weather scenario taking shape late this afternoon through tonight. The cold front was located just south of a Stephenville to San Angelo line at 3 PM with showers and storms developing along and just behind it in West Central Texas. Additional isolated to scattered showers have developed through the afternoon beneath a mid level cap across Central Texas. Aircraft sounding data from AUS indicates the mid level cap still in place, but this is forecast to erode late this afternoon and evening as the front approaches the region. Initially discrete storms could pose a hail threat across the northern Hill Country and Central Texas through the early evening. Signals in hi resolution models then transition into an organized complex of storms, but there are some difference in timing on how fast this happens. Should this happen this could support a threat of damaging straight line winds through the CWA. However, the main concern we are messaging will be the heavy rainfall potential that could lead to flash flooding. Precipitable water values of 1.6-1.8 inches are pooling over the region south of the front. This is nearly 2 standard deviations above average. Initial slow motions of the storms and complex will yield pockets of intense rainfall rates this evening through portions of the overnight, as indicated by runs of the HRRR. Models the past three runs have trended farther south and with higher QPF amounts into much of the southern and eastern Hill Country as well as I-35 corridor. GEFS plumes for both Austin and San Antonio have trended up, with the lowest member at Austin around 2", highest at 4.3", and mean 2.87". Some of the high resolution guidance suggests the highest amounts farther south toward the San Antonio metro area. It is difficult at this time frame to determine where the heavier pockets may occur as there is uncertainty with the mesoscale evolution of the system. But generally 2-4" is expected across the Flash Flood Watch area with isolated amounts up to 7". It is important to stress the flash flooding potential with this system, especially since this will be occurring at night when it is harder to recognize the dangers of flash flooding. Tomorrow's chances for rainfall will depend entirely on how organized the system evolves tonight. With hi resolution guidance trended towards and MCS, the atmosphere may become worked over and stabilized for Tuesday. LONG TERM (Wednesday through Monday)... Chances for showers and thunderstorms will remain in the forecast through the rest of the week with slightly greater chances Thursday as a trough shifts through the region. No concentrated signals appear to warrant hazard mention at this time during the long-term period. Diurnal showers and thunderstorms look to be likely each afternoon through the week as a unsettled and active southern jetstream branch helps promote lift with the continued moist airmass in place. Thursday and Friday appears to be a slightly better concentrated day with the passage of stronger trough axis. Weak ridging over the weekend may help to keep the area dry. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 65 76 63 79 64 / 100 40 10 20 10 Austin Bergstrom Intl Airport 65 76 62 79 63 / 100 50 10 20 10 New Braunfels Muni Airport 66 77 63 79 64 / 100 60 10 20 10 Burnet Muni Airport 62 74 61 76 63 / 90 40 10 20 10 Del Rio Intl Airport 67 79 65 80 64 / 50 40 20 20 30 Georgetown Muni Airport 63 75 62 78 63 / 100 40 10 20 10 Hondo Muni Airport 68 79 63 81 64 / 100 50 10 20 10 San Marcos Muni Airport 66 76 63 79 64 / 100 60 10 20 10 La Grange - Fayette Regional 67 77 64 80 63 / 100 60 10 20 10 San Antonio Intl Airport 67 78 64 80 65 / 100 60 10 20 10 Stinson Muni Airport 69 78 65 80 65 / 100 60 10 20 10 && .EWX WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch through Tuesday morning for the following counties: Atascosa...Bandera...Bastrop...Bexar...Blanco...Burnet... Caldwell...Comal...Fayette...Frio...Gillespie...Gonzales... Guadalupe...Hays...Kendall...Kerr...Lee...Llano...Medina...Real... Travis...Uvalde...Williamson...Wilson...Zavala. && Mesoscale/Aviation...TB3 Synoptic/Grids...TB3 Public Service/Data Collection...33
Hazardous Weather Outlook National Weather Service Austin/San Antonio TX 731 PM CDT Mon Apr 10 2017 TXZ171>173-183>194-202>209-217>225-228-120045- 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- 731 PM CDT Mon Apr 10 2017 This Hazardous Weather Outlook is for South-Central Texas.. .DAY ONE...Tonight through Tuesday morning. A Flash Flood Watch is in effect for most of South Central Texas. Rain totals of 2 to 4 inches with isolated amounts to 7 inches are possible through Tuesday morning...mainly for areas along and east of the Edwards escarpment, including the Interstate 35 corridor. This could lead to flash flooding for these areas. In addition...hail up to one inch in diameter and gusty winds up to 50 mph are possible. However, these threats are secondary to the main flash flooding threat. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday. There is chance for heavy rain to continue Tuesday morning across the extreme southern part of the area. .SPOTTER INFORMATION STATEMENT... Please submit any flooding or severe weather reports to the National Weather Service. TB3
Special Weather Statement National Weather Service Austin/San Antonio TX 826 PM CDT MON APR 10 2017 TXZ171-110215- Llano TX- 826 PM CDT MON APR 10 2017 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN LLANO COUNTY UNTIL 915 PM CDT... At 826 PM CDT, Doppler radar was tracking a strong thunderstorm near Castell, or 14 miles east of Mason, moving slowly east at 15 mph. Nickel size hail and wind gusts up to 50 mph will be possible with this storm. Locations impacted include... Llano, Field Creek, Valley Spring and Castell. PRECAUTIONARY/PREPAREDNESS ACTIONS... This storm may intensify, so be certain to monitor local radio stations and available television stations for additional information and possible warnings from the National Weather Service. To report severe weather, contact your nearest law enforcement agency. They will relay your report to the National Weather Service office in Austin San Antonio. && A Severe Thunderstorm Watch remains in effect until 1100 PM CDT for south central Texas. LAT...LON 3071 9868 3056 9896 3092 9896 3092 9875 TIME...MOT...LOC 0126Z 254DEG 11KT 3079 9899 TB3
Special Weather Statement
National Weather Service Austin/San Antonio TX
1128 PM CDT MON APR 10 2017
TXZ171-188-110530-
Gillespie TX-Llano TX-
1128 PM CDT MON APR 10 2017
...SIGNIFICANT WEATHER ADVISORY FOR LLANO AND NORTHERN GILLESPIE
COUNTIES UNTIL 1230 AM CDT...
At 1125 PM CDT, Doppler radar was tracking strong thunderstorms 10
miles north of Harper, to 5 miles southwest of Llano, moving east at
20 mph.
Wind gusts up to 50 mph and nickel sized hail will be possible with
this storm. Additionally, prolonged heavy rainfall in this area will
result in the threat for flash flooding.
Locations impacted include...
Kingsland, Llano, Buchanan Dam, Gainesville, Granite Shoals,
Horseshoe Bay, Cherry Spring, Doss, Prairie Mountain, Stolz, Castell,
Crabapple, Oxford, Enchanted Rock Station and Sunrise Beach Village.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.
This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.
To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
office in Austin San Antonio.
&&
A Severe Thunderstorm Watch remains in effect until 700 AM CDT for
south central Texas.
LAT...LON 3079 9843 3075 9843 3074 9837 3070 9842
3068 9840 3067 9844 3060 9840 3057 9841
3057 9837 3056 9835 3049 9835 3050 9840
3050 9859 3043 9859 3043 9930 3050 9930
3050 9896 3073 9896 3081 9841
TIME...MOT...LOC 0425Z 268DEG 19KT 3064 9880
TB3The Ft Hood radar (KGRK), 132 km away, was scanning. The volume nearest the first event began at 04:41 UTC.
8 flash flood, 8 hail, 1 thunderstorm wind. Local standard time, as filed.
Thunderstorms produced heavy rain that led to flash flooding closing several county roads west of Llano.
Thunderstorms produced heavy rain that led to flash flooding closing CR 405 at San Fernando Creek.
Thunderstorms produced heavy rain that led to flash flooding closing RM 152 along the Llano River from Castell to Llano.
A thunderstorm produced hail larger than quarters along I-10 just northwest of Boerne.
A thunderstorm produced quarter size hail five miles north of Boerne.
Thunderstorms produced heavy rain that led to flash flooding closing numerous roads in southwestern Kendall County near Boerne.
The Dripping Springs Fire Department relayed a spotter report of a thunderstorm producing quarter size hail.
Thunderstorms produced heavy rain that led to flash flooding with a high water rescue on San Antonio St. in San Marcos. Rains totaled near 8 inches in part of the City of San Marcos and surrounding areas mainly south and east of town.
Thunderstorms produced wind gusts estimated at 70 mph that knocked down five power lines on Cordova Rd. near Geronimo.
Thunderstorms produced heavy rain (up to 8 inches) that led to flash flooding in San Marcos. The I-35 frontage roads from Hwy 80 to McCarty Ln. and Hwy 123 south of the city were closed due to water over the road. Several people had to be rescued from their cars. Emergency Management reported 60 water rescues. There were 35 residential properties damaged and 7 commercial properties damaged. Monetary damage estimates include infrastructure damage and flooded cars. Crop damage is unknown. Nearly 3000 people were without power. Along with the flash flooding, winds up to 70 mph and dime size hail were reported.
Thunderstorms produced heavy rain that led to flash flooding closing FM 78 near Youngs Creek in McQueeney.
Thunderstorms produced heavy rain that led to flash flooding closing FM 758 at Alligator Creek near the New Braunfels Airport.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Texas in 2017Every state in 2017This day in weather historyWarnings in Texas, April 2017
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: 686409, 686412, 686446, 686447, 686448, 686415, 686449, 686450, 686452, 686453, 686417, 686454, 686455, 686459, 686439, 686442, 686444.