Southeasterly flow in the boundary layer brought deep moisture from the Gulf of Mexico into South Central Texas. An upper trough pushed a cold front into this airmass and 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.
Southeasterly flow in the boundary layer brought deep moisture from the Gulf of Mexico into South Central Texas. An upper trough pushed a cold front into this airmass and produced heavy rain that led to flash flooding. There was also an isolated thunderstorm that produced damaging wind gusts.
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 13, 5:05 PM CST, 6 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX 605 PM CDT THU SEP 13 2012 .AVIATION... FOR THE NEXT 24 HOURS...A COLD FRONT WILL PUSH THRU S CENTRAL TX AS AN UPPER AIR TROF TO THE WEST SENDS DISTURBANCES ACROSS THE AREA. WITH A VERY MOIST AND UNSTABLE AIRMASS OVER S TX...NUMEROUS SHRA/TSRA WILL PERSIST AND MAKE FOR VARIABLE CONDITIONS TONIGHT INTO FRIDAY. IFR CIGS AND VSBYS ARE POSSIBLE IN THE SHRA/TSRA...HOWEVER MVFR CIGS WILL GENERALLY PREVAIL. SURFACE WINDS WILL SHIFT TO N-NELY AT 8-12 KNOTS BEHIND THE FRONT AND 10-15 KNOTS AHEAD OF IT. && .PREV DISCUSSION... /ISSUED 316 PM CDT THU SEP 13 2012/ DISCUSSION... COOLER...WET WEATHER IS IN THE OFFING FOR SOUTH CENTRAL TEXAS. A COLD FRONT OVER NORTHWEST TEXAS TO THE BIG BEND WILL SLIDE INTO THE HILL COUNTRY AND WESTERN PORTIONS OF SOUTH CENTRAL TEXAS BY MIDNIGHT...TRUDGING SOUTHEAST OVER MUCH OF THE AREA DURING THE DAY TOMORROW. THE COLD FRONT'S SLOW MOVEMENT WILL BE CAUSED BY AN ELONGATED UPPER TROUGH WELL BEHIND THE SURFACE FRONT EXTENDING FROM THE SOUTHERN U.S. PLAINS TO SOUTHERN NEW MEXICO. THIS UPPER LEVEL TROUGH WILL MOVE LITTLE THROUGH EARLY SATURDAY. DISTURBANCES EJECTING EAST ON THE UNDERSIDE OF THE TROUGH WILL PUSH OVER THE REGION TOMORROW WHICH MAY CAUSE THE FRONT TO SLOW FURTHER. THE FRONT AND MESOSCALE OUTFLOWS WILL INTERACT WITH AN UNCAPPED AND TROPIC- LIKE ATMOSPHERE (PRECIPITABLE WATER VALUES 1.6 AND GREATER) TO PRODUCE EFFICIENT RAIN RATES ACROSS THE AREA. GENERAL 1/2 TO 1 INCH AMOUNTS CAN BE EXPECTED THROUGH TOMORROW AFTERNOON WITH ISOLATED 2 TO 4 INCH TOTALS POSSIBLE...MAINLY OVER SOUTH CENTRAL AND WESTERN PORTIONS. MINOR FLOOD PROBLEMS MAY OCCUR AS A RESULT. HIGHS TOMORROW WILL ONLY REACH INTO THE 70S ACROSS THE HILL COUNTRY AND WESTERN SECTIONS WITH LOWER 80S ALONG THE I-35 CORRIDOR. BY TOMORROW NIGHT GULF MOISTURE WILL CONTINUE TO OVERRUN THE COOL AIR-MASS AND WITH CONTINUED DISTURBANCES ALOFT...A CHANCE OF SHOWERS AND THUNDERSTORMS ARE AGAIN POSSIBLE...WITH LIGHTER RAIN AMOUNTS EXPECTED. THE UPPER TROUGH WILL BEGIN ITS MOVE SATURDAY AND BY SUNDAY NIGHT...THE TROUGH WILL HAVE PUSHED THROUGH THE REGION WITH NORTHWEST FLOW ALOFT AND RAIN CHANCES HAVING DIMINISHED. THROUGH SUNDAY HOWEVER WE'LL MAINTAIN AT LEAST A CHANCE OF SHOWERS AND THUNDERSTORMS OVER MUCH OF THE AREA. AFTER SOME PATCHY MORNING FOG ALONG AND EAST OF THE ESCARPMENT EARLY MONDAY MORNING...SKIES MONDAY WILL TURN PARTLY CLOUDY AND TEMPERATURES WILL CREEP BACK INTO THE 90S WITH DRY WESTERLIES ALOFT. A SHORT WAVE WILL DIG A LONG WAVE TROUGH DEEP INTO THE MISSISSIPPI VALLEY AREA TUESDAY WITH AN ASSOCIATED COLD FRONT PUSHING THROUGH THE REGION. THE FRONT SHOULD PUSH THROUGH DRY WITH LIMITED MOISTURE AHEAD OF THE FRONT. A DRY WEST NORTHWEST FLOW ALOFT WILL DOMINATE THE REGION WEDNESDAY AND THURSDAY WITH COOL MORNINGS AND WARM AFTERNOONS. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 69 83 69 84 70 / 80 70 40 50 50 AUSTIN BERGSTROM INTL AIRPORT 70 83 64 85 65 / 80 70 40 50 50 NEW BRAUNFELS MUNI AIRPORT 70 83 66 85 66 / 80 80 40 50 50 BURNET MUNI AIRPORT 67 78 66 79 67 / 70 70 40 50 40 DEL RIO INTL AIRPORT 70 76 68 80 69 / 90 80 40 40 30 GEORGETOWN MUNI AIRPORT 68 81 67 82 67 / 70 70 40 50 50 HONDO MUNI AIRPORT 70 81 66 83 66 / 90 80 40 50 50 SAN MARCOS MUNI AIRPORT 70 82 66 85 67 / 80 80 40 50 50 LA GRANGE - FAYETTE REGIONAL 71 85 69 86 68 / 60 60 50 40 30 SAN ANTONIO INTL AIRPORT 71 82 69 84 69 / 80 80 40 50 50 STINSON MUNI AIRPORT 71 83 70 85 70 / 80 80 40 50 50 && .EWX WATCHES/WARNINGS/ADVISORIES... NONE. && MESOSCALE/AVIATION...05 SYNOPTIC/GRIDS...01 PUBLIC SERVICE/DATA COLLECTION...33
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX 551 AM CDT THU SEP 13 2012 TXZ171>173-183>194-202>209-217>225-228-141100- 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- 551 AM CDT THU SEP 13 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH CENTRAL TEXAS. .DAY ONE...TODAY AND TONIGHT... AN INCREASING CHANCE OF RAIN...FROM SHOWERS OR THUNDERSTORMS... IS EXPECTED TODAY AND TONIGHT ASSOCIATED WITH A RAIN MAKING DISTURBANCE AND COLD FRONT. THE PRIMARY HAZARDS WILL BE LOCALLY HEAVY RAINFALL AND LIGHTNING ASSOCIATED WITH THE THUNDERSTORMS. THE MAIN THREAT FOR THIS EVENT WILL BE MINOR FLOODING ACROSS STREETS...UNDERPASSES...LOW WATER CROSSINGS AND SMALL STREAMS AND RIVERS. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY... RAIN FROM SHOWERS OR THUNDERSTORMS IS EXPECTED FRIDAY THROUGH SATURDAY. THE PRIMARY HAZARDS WILL BE LOCALLY HEAVY RAINFALL AND LIGHTNING ASSOCIATED WITH THE THUNDERSTORMS. THE MAIN THREAT FOR THIS EVENT WILL BE MINOR FLOODING ACROSS STREETS...UNDERPASSES... LOW WATER CROSSINGS AND SMALL STREAMS AND RIVERS. NO HAZARDOUS WEATHER IS EXPECTED SUNDAY THROUGH WEDNESDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
341 PM CDT THU SEP 13 2012
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0337 PM HEAVY RAIN 2 E GRANITE SHOALS 30.59N 98.36W
09/13/2012 M1.05 INCH BURNET TX COCORAHS
RAINFALL OVER PAST HOUR
&&
EVENT NUMBER EWX1200465
CVPPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
355 PM CDT THU SEP 13 2012
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0337 PM HEAVY RAIN HORSESHOE BAY 30.54N 98.35W
09/13/2012 M4.50 INCH LLANO TX BROADCAST MEDIA
RAINFALL AMOUNT OVER APPROXIMATELY 1.5 HOURS
&&
EVENT NUMBER EWX1200466
CVPPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
456 PM CDT THU SEP 13 2012
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0453 PM HEAVY RAIN 2 N JOHNSON CITY 30.31N 98.41W
09/13/2012 M5.00 INCH BLANCO TX COCORAHS
RAINFALL IN THE PAST HOUR AND 10 MINUTES
&&
EVENT NUMBER EWX1200467
CVPPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
459 PM CDT THU SEP 13 2012
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0445 PM HEAVY RAIN 1 NNW LIBERTY HILL 30.67N 97.92W
09/13/2012 M2.75 INCH WILLIAMSON TX COCORAHS
RAINFALL IN PAST 80 MINUTES
&&
EVENT NUMBER EWX1200468
CVPSPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX 502 PM CDT THU SEP 13 2012 TXZ202-203-132245- KINNEY-UVALDE- 502 PM CDT THU SEP 13 2012 ...SIGNIFICANT WEATHER ADVISORY FOR WESTERN UVALDE AND CENTRAL KINNEY COUNTIES UNTIL 545 PM CDT... AT 457 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED AN AREA OF STRONG THUNDERSTORMS EXTENDING FROM 7 MILES SOUTHEAST OF STANDART TO 6 MILES WEST OF UVALDE...AND MOVING NORTHEAST AT 5 MPH. WIND GUSTS UP TO 40 MPH ARE EXPECTED WITH THESE STORMS...ALONG WITH HEAVY RAIN AND FREQUENT DANGEROUS LIGHTNING. LOCATIONS NEAR THE PATH OF THESE STORMS INCLUDE... UVALDE... BRACKETTVILLE... STANDART... CLINE... ALAMO VILLAGE... LAGUNA... MONTELL... CONCAN... REAGAN WELLS... GARNER STATE PARK... IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A STURDY BUILDING. THE HEAVY RAIN MAY FLOOD LOW LYING AREAS SUCH AS DITCHES...LOW WATER CROSSINGS AND UNDERPASSES. DO NOT DRIVE YOUR VEHICLE ACROSS FLOODED ROADWAYS. LAT...LON 2958 10050 2957 9962 2913 9983 2922 10068 TIME...MOT...LOC 2202Z 207DEG 5KT 2929 10053 2923 9988
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
600 PM CDT THU SEP 13 2012
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0559 PM HEAVY RAIN 5 SW LEANDER 30.51N 97.92W
09/13/2012 M7.15 INCH TRAVIS TX MESONET
RAINFALL OVER PAST 3 HOURS
&&
EVENT NUMBER EWX1200469
CVPThe Ft Hood radar (KGRK), 56 km away, was scanning. The volume nearest the first event began at 23:12 UTC.
6 flash flood, 1 thunderstorm wind. Local standard time, as filed.
Thunderstorms produced heavy rain that caused flash flooding down Big Sandy Creek that washed several docks, that were on dry land near drought stricken Lake Travis, down stream. Upstream rainfall of 7.75 inches in approximately three hours caused a 10 foot rise on the creek.
Thunderstorms produced heavy rain that caused flash flooding closing several streets in Georgetown.
Thunderstorms produced heavy rain that caused flash flooding closing County Road 279 north of County Road 281.
A thunderstorm produced wind gusts estimated at 50 mph that blew the roof off a trailer home.
Thunderstorms produced heavy rain that caused flash flooding closing Orsinger Ln at Sleepy Hollow St, Overbrook Dr at Danville, Sleepy Hollow St at Sunburst St, and Vance Jackson Rd at Orsinger Ln all in San Antonio.
Thunderstorms produced heavy rain that caused flash flooding closing Hwy 473 outside Kendalia.
Thunderstorms produced heavy rain that caused flash flooding closing Hein Rd near Welfare.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Texas in 2012Every state in 2012This day in weather historyWarnings in Texas, September 2012
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: 407346, 407347, 407348, 407349, 407350, 407351, 407352.