Alert archive / Texas / Flash Flood Warnings in 2012

Flash Flood Warning 36, NWS Austin/San Antonio, TX

May 10, 2012Hays County, Travis County, Williamson County, Texas

NWS Austin/San Antonio, TX issued this flash flood warning at May 10, 2012, 8:02 PM CDT for Hays County, Travis County, Williamson County, Texas. It was in force for 118 min. 3 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
May 10, 2012, 8:02 PM CDT (01:02 UTC)
Expired
May 10, 2012, 10:00 PM CDT
In force
118 min
Issued by
NWS Austin/San Antonio, TX
Area
Storm-based polygon
Flood severity
None

Counties Hays County, TX, Travis County, TX, Williamson County, TX

The radar

The Ft Hood radar (KGRK), 57 km from the middle of the area, began a volume at 01:05 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

TimeReportWhereRemark
May 10, 8:50 PM CDTHEAVY RAIN 1.283 Ese Leander, TX1.28 INCHES OF RAINFALL IN 20 MINUTES.
May 10, 9:05 PM CDTHEAVY RAIN 2.241 W Hutto, TX2.00 TO 2.24 INCHES IN ABOUT 20 MINUTES.
May 10, 9:30 PM CDTFLASH FLOOD3 W Driftwood, TXSEVERAL ROADS IN AND AROUND DRIFTWOOD CLOSED DUE TO FLOODING... INCLUDING PARTS OF HIGHWAY 12.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Fort Worth, TX (KFWD), launched 00:00Z, 1.0 hours before the alert went out and 278 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Fort Worth, TX at 00:00Z on 2012-05-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Fort Worth, TX at 00:00Z on 2012-05-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 2 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2229 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
2 m²/s²
0-3 km storm-relative helicity
27 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

129 
WGUS54 KEWX 110102
FFWEWX
TXC209-453-491-110300-
/O.NEW.KEWX.FF.W.0036.120511T0102Z-120511T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
802 PM CDT THU MAY 10 2012

THE NATIONAL WEATHER SERVICE IN AUSTIN SAN ANTONIO HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  HAYS COUNTY...
  TRAVIS COUNTY...
  WILLIAMSON COUNTY...

* UNTIL 1000 PM CDT.

* AT 800 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS HAVE
  DETERMINED THAT RAINFALL ESTIMATES FROM DOPPLER RADAR INDICATE A
  LINE OF THUNDERSTORMS WITH VERY HEAVY RAINFALL APPROACHING
  THE AUSTIN METRO AREA FROM THE WEST. RAINFALL AMOUNTS OF BETWEEN
  ONE AND TWO INCHES WILL OCCUR IN ONE HOUR OR LESS.  

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
  OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  ANDERSON MILL...AUSTIN...AUSTIN BERGSTROM INT AP...CEDAR PARK...
  DRIPPING SPRINGS...GEORGETOWN...PFLUGERVILLE...ROUND ROCK...
  SERENADA...TANGLEWOOD FOREST...TAYLOR...WIMBERLEY...WINDEMERE...
  ANDICE...BEE CAVE...BUDA...COUPLAND...DRIFTWOOD...GEORGETOWN DAM...
  HUTTO...KYLE...LAGO VISTA...LAKEWAY...LEANDER...LIBERTY HILL...
  MANOR...MANSFIELD DAM...MUSTANG RIDGE...ONION CREEK AND
  ROLLINGWOOD.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

RUNOFF FROM HEAVY RAIN WILL FLOOD CREEKS, STREAMS, STREET
INTERSECTIONS, CULVERTS AND UNDERPASSES. LOW LYING PLACES THAT
NORMALLY FLOOD COULD BECOME DEATH TRAPS. DO NOT CROSS ANY FLOODED
AREA. TURN AROUND DON'T DROWN.

&&

LAT...LON 3058 9726 3043 9739 3041 9737 3021 9749
      3002 9771 3005 9775 2985 9799 3006 9826
      3033 9814 3035 9817 3046 9810 3051 9812
      3062 9805 3062 9801 3083 9791

$$
1 follow-up statement
415 
WGUS74 KEWX 110246
FFSEWX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
946 PM CDT THU MAY 10 2012

TXC209-453-491-110300-
/O.CON.KEWX.FF.W.0036.000000T0000Z-120511T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
HAYS TX-TRAVIS TX-WILLIAMSON TX-
946 PM CDT THU MAY 10 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1000 PM CDT FOR
WILLIAMSON...TRAVIS AND HAYS COUNTIES...

AT 940 PM CDT...A BAND OF THUNDERSTORMS EXTENDED ACROSS MUCH OF 
HAYS...TRAVIS AND SOUTHERN WILLIAMSON COUNTIES...MOVING EAST AT 30 
MPH. RAINFALL RATES OF 1 TO 2 INCHES PER HOUR WERE INDICATED BY 
RADAR.

SMALL STREAMS AND CREEKS MAY FLOOD LOW LYING AREAS OVER THE NEXT FEW 
HOURS. MOTORISTS SHOULD BE AWARE THAT LOW WATER CROSSINGS MAY BE 
EXTREMELY DANGEROUS THE NEXT FEW HOURS.  TRAVEL SHOULD BE AT LOW 
SPEEDS SO ONE CAN STOP BEFORE DRIVING INTO DANGEROUS CROSSINGS AND 
BRIDGES. 

LOCATIONS IN THE WARNING AREA INCLUDE SUN CITY...LIBERTY HILL...
WINDEMERE...PFLUGERVILLE...LAKEWAY...LAGO VISTA...WEIR...THRALL...
TAYLOR...SERENADA...ROUND ROCK...LEANDER...HUTTO...GEORGETOWN DAM...
GEORGETOWN...COUPLAND...CEDAR PARK...ANDICE AND ANDERSON MILL.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A TORNADO WATCH REMAINS IN EFFECT UNTIL 300 AM CDT FRIDAY MORNING FOR
SOUTH CENTRAL TEXAS.

&&

LAT...LON 3058 9726 3043 9739 3041 9737 3021 9749
      3002 9771 3005 9775 2985 9799 3006 9826
      3033 9814 3035 9817 3046 9810 3051 9812
      3062 9805 3062 9801 3083 9791

$$

The office that day

Everything else NWS Austin/San Antonio, TX issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 10, 7:21 PM CDTTornado WarningEWXDimmit, Frio, Zavala24 min
May 10, 7:59 PM CDTRiver Flood WarningEWXKerr18 hr
May 10, 8:26 PM CDTSevere Thunderstorm WarningEWXTravis, Williamson49 min
May 10, 8:32 PM CDTRiver Flood WarningEWXVal Verde30 hr
May 10, 8:34 PM CDTAreal Flood AdvisoryEWXBexar116 min
May 10, 9:10 PM CDTFlash Flood WarningEWXBexar, Comal, Guadalupe, Hays3 hr
May 10, 9:59 PM CDTAreal Flood AdvisoryEWXBastrop, Caldwell, Comal, Guadalupe, Hays, Lee and 2 more2 hr
May 10, 10:42 PM CDTFlash Flood WarningEWXBastrop, Caldwell, Guadalupe, Hays, Lee, Travis and 1 more4 hr
May 11, 12:06 AM CDTFlash Flood WarningEWXBexar, Comal3 hr
May 11, 2:37 AM CDTFlash Flood WarningEWXHays113 min

Nearby

Flash Flood Warnings in Texas, 2012Every flash flood warning in 2012

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.