Alert archive / Texas / Flash Flood Warnings in 2012

Flash Flood Warning 49, NWS Austin/San Antonio, TX

July 15, 2012Williamson County, Texas

NWS Austin/San Antonio, TX issued this flash flood warning at Jul 15, 2012, 5:18 PM CDT for Williamson County, Texas. It was in force for 2 hr. 5 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
Jul 15, 2012, 5:18 PM CDT (22:18 UTC)
Expired
Jul 15, 2012, 7:30 PM CDT
In force
2 hr
Issued by
NWS Austin/San Antonio, TX
Area
Storm-based polygon
Flood severity
None

County Williamson County, TX

The radar

The Ft Hood radar (KGRK), 27 km from the middle of the area, began a volume at 22:20 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
Jul 15, 5:59 PM CDTFLASH FLOODBrushy Creek, TXFLASH FLOODING ON BRUSHY CREEK AT COUNTY ROAD 174 AND RED OAK
Jul 15, 6:00 PM CDTHEAVY RAIN 2.756 E Leander, TXRAINFALL OVER THE PAST 2 HOURS
Jul 15, 6:09 PM CDTHEAVY RAIN 31 S Round Rock, TXRAINFALL SINCE 345 PM
Jul 15, 6:30 PM CDTHEAVY RAIN 3.491 Ene Anderson Mill, TXRAINFALL TOTAL SINCE 450 PM
Jul 15, 7:04 PM CDTFLASH FLOODRound Rock, TXEMERGENCY MANAGER REPORTED SEVERE FLOODING IN SW WILLIAMSON COUNTY ALONG WITH EVACUATIONS IN ROUND ROCK NEAR BRUSHY CREEK

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 12:00Z, 10.3 hours before the alert went out and 249 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 12:00Z on 2012-07-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1985 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, Fort Worth, TX at 12:00Z on 2012-07-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 19 square meters per square second.1939Sfc1 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
1985 J/kg
Mixed-layer CIN
-64 J/kg
Mixed-layer LCL
823 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
19 m²/s²
0-3 km storm-relative helicity
101 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.

215 
WGUS54 KEWX 152218
FFWEWX
TXC491-160030-
/O.NEW.KEWX.FF.W.0049.120715T2218Z-120716T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
518 PM CDT SUN JUL 15 2012

THE NATIONAL WEATHER SERVICE IN AUSTIN SAN ANTONIO HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CENTRAL WILLIAMSON COUNTY...

* UNTIL 730 PM CDT.

* AT 515 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  A LINE OF SLOW MOVING THUNDERSTORMS WITH VERY HEAVY RAINFALL       
  EXTENDING FROM ROUND ROCK TO JARRELL. RAINFALL RATES WERE          
  ESTIMATED AT 2 TO 4 INCHES AN HOUR. THIS NORTH/SOUTH LINE OF       
  THUNDERSTORMS WILL IMPACT I-35.

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
  OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  ANDERSON MILL...GEORGETOWN...ROUND ROCK...SERENADA...GEORGETOWN
  DAM...HUTTO...JARRELL...SUN CITY AND WEIR.

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 3084 9751 3082 9747 3048 9755 3050 9759
      3049 9761 3048 9768 3046 9770 3043 9778
      3046 9783 3090 9775

$$
2 follow-up statements
420 
WGUS74 KEWX 152243
FFSEWX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
543 PM CDT SUN JUL 15 2012

TXC491-160030-
/O.CON.KEWX.FF.W.0049.000000T0000Z-120716T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WILLIAMSON TX-
543 PM CDT SUN JUL 15 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 730 PM CDT FOR
CENTRAL WILLIAMSON COUNTY...

AT 535 PM CDT...THUNDERSTORMS PRODUCING VERY HEAVY RAIN CONTINUE
OVER THE WARNED AREA. MOVEMENT WAS EAST AT 5 TO 10 MPH. DOPPLER 
RADAR ESTIMATED RAINFALL RATES OF 2 TO 4 INCHES AN HOUR. UNDERPASSES
ASSOCIATED WITH I-35 HAVE THE GREATEST RISK OF FLASH FLOODING.

LOCATIONS IN THE WARNING AREA INCLUDE SUN CITY...WEIR...SERENADA...
JARRELL...GEORGETOWN DAM AND GEORGETOWN.

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 3084 9751 3082 9747 3048 9755 3050 9759
      3049 9761 3048 9768 3046 9770 3043 9778
      3046 9783 3090 9775

$$
966 
WGUS74 KEWX 152312
FFSEWX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
612 PM CDT SUN JUL 15 2012

TXC491-160030-
/O.CON.KEWX.FF.W.0049.000000T0000Z-120716T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WILLIAMSON TX-
612 PM CDT SUN JUL 15 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 730 PM CDT FOR
CENTRAL WILLIAMSON COUNTY...

AT 605 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS CONTINUED TO 
DETECT THUNDERSTORM PRODUCING VERY HEAVY RAIN OVER THE WARNED AREA.
THE THUNDERSTORMS WERE MOVING TO THE EAST AND NORTHEAST AT 5 TO 10 
MPH. DOPPLER RAINFALL RATES WERE ESTIMATED 2 TO 4 INCHES AN HOUR 
BETWEEN BRUSHY CREEK AND ROUND ROCK.

LOCATIONS IN THE WARNING AREA INCLUDE SUN CITY...WEIR...SERENADA...
JARRELL...GEORGETOWN DAM AND GEORGETOWN.

LAW ENFORCEMENT HAS REPORTED FLASH FLOODING ON BRUSHY CREEK AT 
COUNTY ROAD 174 AND RED OAK. 

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 3084 9751 3082 9747 3048 9755 3050 9759
      3049 9761 3048 9768 3046 9770 3043 9778
      3046 9783 3090 9775

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 15, 12:25 AM CDTAreal Flood AdvisoryEWXTravis, Williamson2 hr
Jul 15, 12:40 AM CDTFlash Flood WarningEWXTravis, Williamson3 hr
Jul 15, 4:59 PM CDTAreal Flood AdvisoryEWXWilliamson2 hr
Jul 15, 6:03 PM CDTAreal Flood AdvisoryEWXTravis117 min
Jul 15, 6:31 PM CDTFlash Flood WarningEWXTravis3 hr
Jul 15, 6:40 PM CDTAreal Flood AdvisoryEWXBandera, Medina110 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.