Alert archive / Texas / Flash Flood Warnings in 2012

Flash Flood Warning 37, NWS Austin/San Antonio, TX

May 10, 20124 counties in Texas

NWS Austin/San Antonio, TX issued this flash flood warning at May 10, 2012, 9:10 PM CDT for 4 counties in Texas. It was in force for 3 hr. 2 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, 9:10 PM CDT (02:10 UTC)
Expired
May 11, 2012, 12:00 AM CDT
In force
3 hr
Issued by
NWS Austin/San Antonio, TX
Area
Storm-based polygon
Flood severity
None

Counties Bexar County, TX, Comal County, TX, Guadalupe County, TX, Hays County, TX

The radar

The Austin/San Antonio radar (KEWX), 45 km from the middle of the area, began a volume at 02:12 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, 9:48 PM CDTFLASH FLOOD5 Sw San Antonio, TXTHERE ARE CURRENTLY 7 ROADS IN AND AROUND SAN ANTONIO CLOSED DUE TO FLOODING.
May 10, 11:32 PM CDTFLASH FLOODN San Antonio, TXTHERE ARE CURRENTLY 17 ROADS CLOSED IN AND AROUND SAN ANTONIO DUE TO FLOODING.

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

The nearest sounding before it

Del Rio, TX (KDRT), launched 00:00Z, 2.2 hours before the alert went out and 230 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, Del Rio, TX at 00:00Z on 2012-05-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 67 joules per kilogram.LCLLFCEL10008507005003002001001 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, Del Rio, TX at 00:00Z on 2012-05-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 94 square meters per square second.1939587897Sfc1 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
67 J/kg
Mixed-layer CIN
-176 J/kg
Mixed-layer LCL
934 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
94 m²/s²
0-3 km storm-relative helicity
20 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

Open this sounding in Storm Lab

The text

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

046 
WGUS54 KEWX 110210
FFWEWX
TXC029-091-187-209-110500-
/O.NEW.KEWX.FF.W.0037.120511T0210Z-120511T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

THE NATIONAL WEATHER SERVICE IN AUSTIN SAN ANTONIO HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  BEXAR COUNTY...
  COMAL COUNTY...
  WEST CENTRAL GUADALUPE COUNTY...
  SOUTHERN HAYS COUNTY...

* UNTIL MIDNIGHT CDT.

* AT 907 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS HAVE
  DETERMINED THAT RAINFALL ESTIMATES FROM DOPPLER RADAR INDICATE 
  FLASH FLOODING ACROSS THE SAN ANTONIO METROPOLITAN AREA TO NEW 
  BRAUNFELS...AND SAN MARCOS.  RAINFALL RATES OF 1 TO 2 INCHES
  PER HOUR WILL OCCUR WITH THESE STORMS.    

* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...CANYON LAKE
  DAM...NEW BRAUNFELS...SAN ANTONIO...UNIVERSAL CITY...ALAMO
  HEIGHTS...BULVERDE...CALAVERAS LAKE...CHINA GROVE...CIBOLO...CROSS
  MOUNTAIN...ELMENDORF...FAIR OAKS RANCH...FISCHER...GARDEN RIDGE...
  HELOTES...HILL COUNTRY VILLA...HOLLYWOOD PARK...KIRBY...LACKLAND
  AFB...LEON SPRINGS...LEON VALLEY...LIVE OAK...MARION...OLMOS
  PARK...SCHERTZ...SEA WORLD...SELMA...SHAVANO PARK...SOMERSET AND
  SPRING BRANCH.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IT IS HARD TO RECOGNIZE THE DANGERS OF FLOODING AT NIGHT. IF FLOOD
WATERS RISE ACT QUICKLY. DO NOT STAY IN FLOOD PRONE AREAS.

&&

LAT...LON 2925 9880 2970 9880 2972 9878 2972 9874
      2975 9866 2975 9859 3006 9826 2983 9796
      2949 9814 2948 9812 2945 9812 2911 9841

$$
2 follow-up statements
798 
WGUS74 KEWX 110232
FFSEWX

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

TXC029-091-187-209-110500-
/O.CON.KEWX.FF.W.0037.000000T0000Z-120511T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
GUADALUPE TX-HAYS TX-BEXAR TX-COMAL TX-
932 PM CDT THU MAY 10 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL MIDNIGHT CDT FOR
COMAL...BEXAR...SOUTHERN HAYS AND WEST CENTRAL GUADALUPE COUNTIES...

AT 925 PM CDT...A COMPLEX OF SHOWERS AND THUNDERSTORMS WAS OVER MUCH 
OF BEXAR AND COMAL COUNTIES MOVING EAST AT 30 MPH. RAINFALL RATES 
CONTINUE IN THE ONE TO TWO INCH PER HOUR RANGE. 

SOME SECONDARY ROADS AND LOW WATER CROSSINGS MAY FLOOD ACROSS COMAL 
AND OVER SOUTHERN AND EASTERN BEXAR COUNTIES OVER THE NEXT FEW 
HOURS.  MOTORISTS SHOULD NOT ENTER LOW WATER CROSSINGS AS 80 PERCENT 
OF FLOOD FATALITIES OCCUR THIS WAY. 

LOCATIONS IN THE WARNING AREA INCLUDE FISCHER.

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.

WHEN WATER COVERS THE ROAD...TURN AROUND DON'T DROWN. THE LIFE YOU
SAVE MAY BE YOUR OWN.

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

&&

LAT...LON 2925 9880 2970 9880 2972 9878 2972 9874
      2975 9866 2975 9859 3006 9826 2983 9796
      2949 9814 2948 9812 2945 9812 2911 9841

$$
769 
WGUS74 KEWX 110419
FFSEWX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1119 PM CDT THU MAY 10 2012

TXC029-091-187-209-110500-
/O.CON.KEWX.FF.W.0037.000000T0000Z-120511T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
GUADALUPE TX-HAYS TX-BEXAR TX-COMAL TX-
1119 PM CDT THU MAY 10 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL MIDNIGHT CDT FOR
COMAL...BEXAR...SOUTHERN HAYS AND WEST CENTRAL GUADALUPE COUNTIES...

AT 1115 PM CDT...ISOLATED LOW WATER CROSSINGS AND LOCAL ROADS ACROSS 
THE COMAL...BEXAR...HAYS AND GUADALUPE COUNTIES CONTINUE FLOODED AT 
THIS HOUR AS THEY SLOWLY DRAIN. THE SHOWER ACTIVITY HAS ENDED FOR 
NOW...HOWEVER...FLOODED AREAS WILL CONTINUE FOR THE NEXT SEVERAL 
HOURS...ESPECIALLY EAST OF THE SAN ANTONIO AND AUSTIN METRO AREAS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

WHEN WATER COVERS THE ROAD...TURN AROUND DON'T DROWN. THE LIFE YOU
SAVE MAY BE YOUR OWN.

IT IS HARD TO RECOGNIZE THE DANGERS OF FLOODING AT NIGHT. IF FLOOD
WATERS RISE ACT QUICKLY. DO NOT STAY IN FLOOD PRONE AREAS.

&&

LAT...LON 2925 9880 2970 9880 2972 9878 2972 9874
      2975 9866 2975 9859 3006 9826 2983 9796
      2949 9814 2948 9812 2945 9812 2911 9841

$$

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, 8:02 PM CDTFlash Flood WarningEWXHays, Travis, Williamson118 min
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, 9:59 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.