3 flash flood, 1 thunderstorm wind, as filed by the National Weather Service.
Every event with a place to put it; 3 filed by county or forecast zone are drawn at its center, in a lighter ring. 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 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 11, 1:10 PM CST, 3 hours 25 minutes earlier.
SOUTH CENTRAL TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
210 PM CDT THU SEP 11 2003
SAT PIXS THIS AFTN SHOW STG S/W ENERGY ROTATING AROUND THE BASE OF
THE UPR TROF IN THE FORM OF DEVELOPING CONVECTION OVER WEST TX.
THIS S/W ENERGY WHICH IS EXPECTED TO GENERATE A SQUALL LINE...WOULD
FAVOR THE GFS SOLN OF A FASTER/STRONGER UPR TROF THAN INDICATED BY
THE LATEST ETA. AM THEREFORE LEANING TOWARD THE GFS SOLN WHICH IS
ALSO MORE IN LINE WITH THE UKMET/ECMWF(SEE HPC MODEL DISC). THE GFS
QPF AMOUNTS ARE QUITE IMPRESSIVE OVER THE EWX CWA AND PREFER A BLEND
OF THE GFS AREA WITH ETA AMOUNTS WHICH MATCHES THE WGRFC QPF. THE
EASTWARD MOVG SQUALL LINE WILL INTERACT WITH INCREASING SLY INFLO OF
GULF MOISTURE AND PWS AOA 2 INCHES. STG SFC CONVERGENCE NEAR THE
SFC TROF/FRONT ALONG WITH UPR DIFFLUENCE AHEAD OF THE UPR TROF WILL
CREATE A FAVORABLE ENVIRONMENT FOR NORTHEASTWARD TRAINING CELLS.
WILL ALSO CONT TO MENTION OF SVR THIS EVENING FOR THE NWRN CWA AS
MENTION IN AN EARLIER AFD.
THEREFORE NEED TO EXPAND THE FFA TO INCLUDE MUCH OF THE HILL COUNTRY
THRU FRIDAY...ALTHOUGH EXPECT HEAVIEST RAINS TO HAVE MOVED EAST OUT
OF THE HILL COUNTRY BY FRI AFTN...WITH HEAVY RAIN POTENTIAL CONTG IN
THE EAST. SHOULD SEE RAPID CLEARING IN THE WRN CWA BY FRI AFTN AND
IN THE EAST FRI EVENING. PLEASANT-QUIET...COOLER/DRIER WEEKEND IN
STORE FOR S TX AS THE SFC RDG PREVAILS.
GENERALLY DRY WESTERLY UPR FLOW TO PREVAIL OVER THE WEEKEND INTO
EARLY NEXT WEEK WITH A SHALLOW RETURN FLOW RESUMING BY MID WEEK AS
THE NEXT UPR TROF DIGS INTO THE GREAT BASIN.
AUS TB 067/081 064/088 064 883
BBBBB 086/060 086/060 087/063 090/061 090 00000000000
DRT BU 068/087 062/089 062 841
BBBBB 089/064 089/067 090/067 094/068 094 00000000000
SAT TB 069/083 063/088 063 883
BBBBB 087/063 089/065 089/068 092/066 092 00000000000
.EWX...FLASH FLOOD WATCH TONIGHT AND FRIDAY FOR THE HILL COUNTRY
AND MUCH OF SOUTH CENTRAL TEXAS.TXZ171>173-183>194-202>209-217>225-228-121100- HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX 600 AM CDT THU SEP 11 2003 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH CENTRAL TEXAS. .DAY ONE...TODAY AN APPROACHING UPPER LEVEL TROUGH AND COLD FRONT WILL INTERACT WITH A MOIST AIRMASS TO PRODUCE SHOWERS AND THUNDERSTORMS. SCATTERED RAINS WILL DEVELOP TODAY...THEN BECOME NUMEROUS TO WIDESPREAD LATER THIS AFTERNOON INTO TONIGHT. HEAVY RAINFALL IS LIKELY BEGINNING LATER THIS AFTERNOON THEN CONTINUING THROUGH TONIGHT. THESE RAINS WILL LIKELY CAUSE FLOODING PROBLEMS WITH THE GREATEST THREAT ALONG AND EAST OF A BURNET TO SAN ANTONIO TO JOURDANTON LINE WHERE A FLASH FLOOD WATCH HAS BEEN ISSUED. DANGEROUS LIGHTNING AND GUSTY WINDS CAN ALSO BE EXPECTED...WHILE HAIL MAY APPROACH SEVERE LEVELS. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY. NUMEROUS TO WIDESPREAD SHOWERS AND THUNDERSTORMS WILL BE ONGOING FRIDAY AS AN UPPER LEVEL TROUGH AND COLD FRONT MOVE ACROSS THE AREA. HEAVY RAINFALL IS LIKELY INTO MUCH OF FRIDAY. THROUGH FRIDAY...RAINFALL AMOUNTS WILL AVERAGE 1 TO 3 INCHES WITH ISOLATED TOTALS OF 3 TO 5 INCHES OR HIGHER POSSIBLE. FLOODING PROBLEMS WILL LIKELY BE ONGOING WITH THE GREATEST THREAT ALONG AND EAST OF A BURNET TO SAN ANTONIO TO JOURDANTON LINE WHERE A FLASH FLOOD WATCH HAS BEEN ISSUED. DANGEROUS LIGHTNING AND GUSTY WINDS CAN ALSO BE EXPECTED... WHILE HAIL MAY APPROACH SEVERE LEVELS. THE RAINS WILL END FROM THE WEST FRIDAY NIGHT INTO EARLY SATURDAY. .SPOTTER INFORMATION STATEMENT... SOME SPOTTER ACTIVATION MAY BE REQUIRED TODAY THROUGH FRIDAY.
The national radar mosaic for the moment the first event began.
3 flash flood, 1 thunderstorm wind. Local standard time, as filed.
Severe thunderstorms winds estimated at 60 knots blew down power lines in eastern Llano County.
Late on September 11, in advance of an upper level disturbance approaching from the west, a line of thunderstorms formed west of Llano and moved through the county. Storms produced a general 1 to 2 inch rainfall with isolated totals to near 4 inches northwest of Llano. Lower Colorado River Authority personnel reported creeks out of banks in the eastern part of the county as a result of the heavy rainfall.
Late on September 11, the line of showers and thunderstorms that had formed over the Hill Country moved into the IH35 corridor. Heavy rain fell briefly from the southern part of Hays County across much of Comal County. The storm line produced a countywide1inch rain, with 2 inches near San Marcos. Brief flash flooding was reported in San Marcos with damage limited to streets and roads.
Late on September 11, the line of showers and thunderstorms that had formed over the Hill Country moved into the IH35 corridor. Heavy rain fell briefly from the southern part of Hays County across much of Comal County. The line of storms produced a general 1inch rainfall, with 3 inches just west of New Braunfels. Brief flash flooding was reported across New Braunfels as streets became flooded and barricades were put up across the low water crossings. Damage was reported to streets and roads.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Texas in 2003Every state in 2003This day in weather historyWarnings in Texas, September 2003
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: 5371620, 5371978, 5371979, 5372050.