A dryline and weak upper level short wave trough produced a line of thunderstorms one of which caused severe wind gusts in Williamson County.
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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 dryline and weak upper level short wave trough produced a line of thunderstorms one of which caused severe wind gusts in Williamson County.
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 26, 6:05 PM CST, 1 hour 25 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX 705 PM CDT MON SEP 26 2011 .DISCUSSION... SEE BELOW FOR 00Z AVIATION DISCUSSION. && .AVIATION... VFR CONDITIONS WILL GENERALLY PREVAIL THROUGH THIS EVENING. AN AREA OF CONVECTION ACROSS THE HILL COUNTRY IS EXPECTED TO CONTINUE THROUGH THE EVENING HOURS. HAVE INCLUDED CB THROUGH ABOUT 03/04Z AT KAUS AND KDRT...BUT SHRA/TSRA SHOULD STAY NORTH OF TAF TERMINALS WITH THE MAJORITY OF THE ACTIVITY BETWEEN KT82 AND KGTU. CONVECTION IS EXPECTED TO DIE OFF WITH THE LOSS OF DIURNAL HEATING THIS EVENING AND IS NOT ANTICIPATED TO PERSIST BEYOND 04Z. SE-SLY SFC WINDS OF 10 TO 15 KTS THIS EVENING WILL ENABLE GOOD MOISTURE ADVECTION INTO THE LOWER LEVELS...RESULTING A STRATUS DECK DEVELOPING OVERNIGHT MAINLY ALONG AND SOUTHEAST OF THE I-35 CORRIDOR. MVFR CIGS WILL DEVELOP AT KSAT/KSSF BY 09/10Z AND SPREAD TO KAUS BY 10/11Z. GOOD VERTICAL MIXING IN THE MID-MORNING HOURS WILL ENABLE THE STRATUS TO LIFT/BURN OFF BY 14/15Z...WITH VFR CONDITIONS PREVAILING THROUGH THE REMAINDER OF THE TAF PERIOD. SE- SLY SFC WINDS WILL DECREASE TO AOB 10 KTS OVERNIGHT BEFORE INCREASING AGAIN TO 10 TO 15 KTS AFTER 15Z. && .PREV DISCUSSION... /ISSUED 514 PM CDT MON SEP 26 2011/ UPDATE... QUICK UPDATE TO EXPAND POPS. DISCUSSION... A BROKEN LINE OF CONVECTION SPREAD ACROSS THE HILL COUNTRY WILL CONTINUE TO GENERATE ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS THROUGH THIS EVENING. THE BEST COVERAGE WILL GENERALLY BE ACROSS THE EASTERN HILL COUNTRY AND ADJACENT AREAS. HOWEVER...BACK-BUILDING AT THE TAIL-END OF THE SYSTEM INDICATES THE POTENTIAL FOR AN ISOLATED STORM TO REACH AS FAR SOUTH AS HIGHWAY 90. QPF AMOUNTS APPEAR TO BE LACKLUSTER THROUGH THE NEXT FEW HOURS AS MUCH OF THE RAIN WILL EVAPORATE BEFORE HITTING THE GROUND THANKS TO HOT TEMPS AT THE SFC AND THROUGH THE BOUNDARY LAYER. ADDITIONAL DEVELOPMENT IS EXPECTED THROUGH THE EVENING HOURS...WITH A BETTER SHOT AT MEASURABLE PRECIPITATION. STRONG OUTFLOWS AND GUSTY WINDS REMAIN A POSSIBILITY THROUGH THIS EVENING. HAVE EXPANDED SLIGHT CHANCE POPS TO AREAS ALONG AND NORTH OF A LINE FROM EAGLE PASS TO SAN ANTONIO TO LA GRANGE...WITH THE HIGHEST POPS (STILL 20 PERCENT FOR THE TIME BEING UNTIL BETTER COVERAGE DEVELOPS) CONCENTRATED ACROSS THE HILL COUNTRY EASTWARD TO THE AUSTIN METRO AREA. NEW ZONES WILL BE OUT SHORTLY. PREV DISCUSSION... /ISSUED 320 PM CDT MON SEP 26 2011/ DISCUSSION... ABOVE NORMAL HIGHS TO PERSIST FOR MUCH OF THE WORK WEEK BEFORE A COLD FRONT FINALLY BRINGS NEAR NORMAL TEMPERATURES INTO THE AREA FRIDAY INTO THE WEEKEND. DEEP UPPER LOW REMAINS NEARLY CUT OFF FROM THE PREDOMINANT WESTERLIES TO HELP PROMOTE CONTINUED UPPER RIDGING OVER THE WESTERN HALF OF THE US. THE PATTERN ALSO CONTINUES TO PROLONG ELEVATED FIRE WEATHER CONDITIONS...WITH MODERATE WIND GUSTS AND CHANGING WIND DIRECTIONS BEING THE PRIMARY CONCERN. IN THE SHORT TERM...A COLLECTION OF SHORT WAVE DISTURBANCES ARE MOVING IN WESTERLY FLOW ALOFT THAT IS UNDERCUTTING THE WRN US UPPER RIDGE. THESE DISTURBANCES CAN BE HARD TO DEFINE THROUGH SATELLITE IMAGERY DUE TO THE LACK OF MOISTURE...BUT SOME INDIVIDUAL FEATURES CAN BE SEEN LATE THIS AFTERNOON SOUTH OF THE AZ BORDER...OVER CENTRAL NM...AND THE SMALLER ONE MENTIONED EARLIER TO BE MOVING ACROSS WEST CENTRAL TX. A MIXED OUT DRY-LINE OVER THE I-35 CORRIDOR WILL ALSO MAKE CONVECTIVE INITIATION DIFFICULT...ESPECIALLY CONSIDERING THE LACK OF SURFACE BASED CUMULUS. WILL EXPAND ISOLATED POPS/WX DEEPER INTO THE HILL COUNTRY TO NEAR FREDERICKSBURG...AND HAVE THE HWO MENTION GUSTY WINDS AS TRIPLE DIGIT HEAT HAS CONFIDENCE SLIGHTLY INCREASED ON CONVECTIVE INITIATION SOMEWHERE IN THIS AREA. THESE FEATURES WILL AGAIN BE A FOCUS TUESDAY AS THE BROADER WEATHER PATTERN DOES NOT CHANGE MUCH UNTIL WEDNESDAY. THE DRIER ECMWF APPEARS TO HAVE THE BETTER HANDLE ON MEDIUM RANGE PROJECTIONS IN DEVELOPING THE WRN US RIDGE...BUT SOME GFS INFLUENCE WAS FACTORED INTO ALLOWING FOR MORE MOISTURE AND INSTABILITY UNDERCUTTING THE RIDGE ALONG THE SRN US BORDER WED- FRI. THE SLOWER THAN PROJECTED TRENDS OF THE CUT-OFF LOW SHOULD SUPPORT MORE ABOVE NORMAL TEMPS...BUT THE MOISTURE...AND POSSIBILITY OF FURTHER DESTABILIZATION TO BE DRAWN IN FROM HURRICANE HILLARY KEEPS THE TEMPERATURES IN THIS FORECAST ON A GRADUAL DOWNWARD TREND...WHILE LOW CONFIDENCE ISOLATED POPS CONTINUE OFF AND ON THROUGH THURSDAY. A MORE SIGNIFICANT TREND SHOULD BE NOTICED WHEN THE FRONTAL PASSAGE FINALLY GETS TRACTION FROM A STRONGER SURFACE HIGH EARLY FRIDAY. THIS FRONTAL PUSH SHOULD BRING ABOUT A MORE NOTICEABLE AIR MASS CHANGE WITH DRIER AIR AND THE REMOVAL OF POPS. STILL AM NOT CONFIDENT THAT THE PACIFIC MOISTURE TAP WILL BE CUT OFF...BUT WOULD EXPECT PARTLY CLOUDY SKIES FROM MOSTLY MID AND HIGH LEVEL CLOUDS THIS WEEKEND. FIRE WEATHER... ELEVATED FIRE WEATHER CONDITIONS CONTINUE TO BE MENTIONED FOR THIS AFTERNOON AND THIS EVENING...AND WILL BE ADDED FOR TUESDAY AFTERNOON. THE REASONING IS SHIFTED LESS ON THE GENERAL AFTERNOON GUSTY WINDS AND MORE ON THE CONCERN FOR OUTFLOW WINDS FROM CONVECTION ON A HOT DAY. INCREASED RH VALUES AND INCREASING MID LEVEL CLOUD COVER SHOULD HELP LIMIT THE POTENTIAL FOR A RED FLAG EVENT. THE COLD FRONT ON FRIDAY SHOULD ALSO BE MONITORED AS POOR TIMING OR A SHIFT BACK TO A DRYING TREND COULD OCCUR. CLIMATE... RECORD HIGHS TODAY TUESDAY SAT 103/2005 102/2005 AUS 107/2005 105/1953 ATT 107/2005 103/2005 DRT 106/2005 104/2005 && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 74 100 71 99 73 / 20 20 20 20 10 AUSTIN BERGSTROM INTL AIRPORT 70 99 69 98 69 / 20 20 20 20 10 NEW BRAUNFELS MUNI AIRPORT 72 99 74 98 69 / 10 20 20 20 10 BURNET MUNI AIRPORT 71 98 68 97 70 / 20 20 20 20 10 DEL RIO INTL AIRPORT 72 101 73 98 71 / 10 10 10 20 10 GEORGETOWN MUNI AIRPORT 70 97 68 97 69 / 20 20 20 20 10 HONDO MUNI AIRPORT 71 101 70 99 69 / 10 10 10 20 10 SAN MARCOS MUNI AIRPORT 73 98 71 97 71 / 10 20 20 20 10 LA GRANGE - FAYETTE REGIONAL 74 97 73 96 72 / 10 20 20 20 10 SAN ANTONIO INTL AIRPORT 74 99 73 97 73 / 10 20 20 20 10 STINSON MUNI AIRPORT 73 101 72 99 74 / - 10 10 20 10 && .EWX WATCHES/WARNINGS/ADVISORIES... NONE. && MESOSCALE/AVIATION...09 SYNOPTIC/GRIDS...25 PUBLIC SERVICE/DATA COLLECTION...32
HAZARDOUS WEATHER OUTLOOK...UPDATED NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX 345 PM CDT MON SEP 26 2011 TXZ171>173-183>194-202>209-217>225-228-271200- 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- 345 PM CDT MON SEP 26 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH CENTRAL TEXAS. .DAY ONE...THIS AFTERNOON AND TONIGHT... ISOLATED THUNDERSTORMS ARE POSSIBLE THIS EVENING ACROSS THE NORTHEASTERN PORTIONS OF SOUTH CENTRAL TEXAS. ANY STORMS THAT DEVELOP WILL HAVE THE POTENTIAL TO PRODUCE GUSTY WINDS AND OUTFLOW WINDS. BECAUSE OF THE GUSTY WIND THREAT...ELEVATED FIRE WEATHER CONDITIONS ARE POSSIBLE DURING THE EVENING ACROSS THE NORTHEASTERN PORTIONS OF SOUTH CENTRAL TEXAS. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY... ISOLATED THUNDERSTORMS ARE POSSIBLE ACROSS THE NORTHERN HALF OF SOUTH CENTRAL TEXAS TUESDAY AFTERNOON AND EVENING. ANY STORMS THAT DEVELOP WILL HAVE THE POTENTIAL TO PRODUCE GUSTY WINDS AND OUTFLOW WINDS. THIS WILL CAUSE ELEVATED FIRE WEATHER CONDITIONS ACROSS THE NORTHERN HALF OF SOUTH CENTRAL TEXAS...MAINLY DURING THE AFTERNOON AND INTO THE EVENING. AFTER TUESDAY EVENING NO HAZARDOUS WEATHER IS EXPECTED. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX 632 PM CDT MON SEP 26 2011 TXZ172-270015- BURNET- 632 PM CDT MON SEP 26 2011 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN BURNET COUNTY UNTIL 715 PM CDT... AT 627 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A STRONG THUNDERSTORM 8 MILES NORTHEAST OF TOW...OR 12 MILES NORTH OF BUCHANAN DAM...MOVING EAST AT 30 MPH. WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THIS STORM ALONG WITH PENNY SIZE HAIL. LOCATIONS NEAR THE PATH OF THIS STORM INCLUDE... LAKE VICTOR... SUNNYLANE...
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
705 PM CDT MON SEP 26 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0655 PM HAIL 10 NE TOW 30.98N 98.34W
09/26/2011 E0.25 INCH BURNET TX PUBLIC
PEA SIZE HAIL... HEAVY RAIN AND STRONG WINDS.
&&
EVENT NUMBER EWX1100318
PMSPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX 721 PM CDT MON SEP 26 2011 TXZ172-173-270115- BURNET-WILLIAMSON- 721 PM CDT MON SEP 26 2011 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN BURNET AND NORTHWESTERN WILLIAMSON COUNTIES UNTIL 815 PM CDT... AT 716 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 6 MILES SOUTHWEST OF COPPERAS COVE TO INKS LAKE STATE PARK...AND MOVING EAST AT 15 MPH. HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THESE STORMS. FREQUENT LIGHTNING IS ALSO EXPECTED. LOCATIONS NEAR THE PATH OF THESE STORMS INCLUDE... BURNET... BERTRAM... WATSON... SHADY GROVE... JOPPA... BRIGGS... OATMEAL... MAHOMET... FLORENCE... ANDICE...
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
822 PM CDT MON SEP 26 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0821 PM HAIL 2 NW BRIGGS 30.89N 97.94W
09/26/2011 E0.70 INCH BURNET TX PUBLIC
DIME SIZE HAIL... HEAVY RAIN AND LOTS OF LIGHTNING.
&&
EVENT NUMBER EWX1100319
PMThe Ft Hood radar (KGRK), 45 km away, was scanning. The volume nearest the first event began at 01:27 UTC.
1 thunderstorm wind. Local standard time, as filed.
A thunderstorm produced wind gusts estimated at 58 mph which knocked down powerlines along Ranch Road 2338.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Texas in 2011Every state in 2011This day in weather historyWarnings in Texas, September 2011
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: 349810.