Alert archive / Texas / Flash Flood Warnings in 2012

Flash Flood Warning 39, NWS Houston/Galveston, TX

July 11, 20125 counties in Texas

NWS Houston/Galveston, TX issued this flash flood warning at Jul 11, 2012, 10:06 AM CDT for 5 counties in Texas. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 11, 2012, 10:06 AM CDT (15:06 UTC)
Expired
Jul 11, 2012, 1:00 PM CDT
In force
3 hr
Issued by
NWS Houston/Galveston, TX
Area
Storm-based polygon
Flood severity
None

Counties Brazoria County, TX, Colorado County, TX, Jackson County, TX, Matagorda County, TX, Wharton County, TX

The radar

The Houston radar (KHGX), 115 km from the middle of the area, began a volume at 15:06 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.

The nearest sounding before it

Corpus Christi, TX (KCRP), launched 12:00Z, 3.1 hours before the alert went out and 180 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, Corpus Christi, TX at 12:00Z on 2012-07-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2040 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Corpus Christi, TX at 12:00Z on 2012-07-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 11 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
2040 J/kg
Mixed-layer CIN
-8 J/kg
Mixed-layer LCL
702 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
11 m²/s²
0-3 km storm-relative helicity
58 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.

119 
WGUS54 KHGX 111506
FFWHGX
TXC039-089-239-321-481-111800-
/O.NEW.KHGX.FF.W.0039.120711T1506Z-120711T1800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1006 AM CDT WED JUL 11 2012

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY  HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  WHARTON COUNTY IN SOUTHEAST TEXAS...
  BRAZORIA COUNTY IN SOUTHEAST TEXAS...
  EXTREME SOUTHWESTERN COLORADO COUNTY IN SOUTHEAST TEXAS...
  MATAGORDA COUNTY IN SOUTHEAST TEXAS...
  JACKSON COUNTY IN SOUTH CENTRAL TEXAS...

* UNTIL 100 PM CDT

* AT 952 AM CDT...DOPPLER RADAR CONTINUES TO SHOW RAINFALL 
  WITH EMBEDDED THUNDERSTORMS ACROSS THE WARNED AREA. A BROAD SWATH 
  OF 3 TO 10 INCHES HAVE RAIN HAS ALREADY FALLEN WITH THE HEAVIEST 
  GENERALLY CENTERED ALONG A LAKE TEXANA TO BLESSING TO WADSWORTH TO 
  SARGENT TO WEST FREEPORT LINE. STREET FLOODING 
  CONTINUES...ESPECIALLY IN MATAGORDA COUNTY IN AND AROUND BLESSING. 
  RAINFALL RATES HAVE DROPPED OFF FROM EARLIER LEVELS...BUT WITH 
  SATURATED GROUNDS...ADDITIONAL RAINS...EVEN LIGHT TO MODERATE WILL 
  FURTHER CONTRIBUTE TO ONGOING FLOODING. DO NOT DRIVE ACROSS WATER 
  COVERED ROADS! 

* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  LAKE JACKSON...BAY CITY...ANGLETON...FREEPORT...EL CAMPO...CLUTE...
  EDNA...PALACIOS...WEST COLUMBIA...SWEENY...RICHWOOD...BRAZORIA...
  WILD PEACH VILLAGE...JONES CREEK...GANADO...INEZ...DANBURY...VAN
  VLECK...OYSTER CREEK...MARKHAM...BOLING-IAGO...HOLIDAY LAKES...
  BAILEY'S PRAIRIE...SURFSIDE BEACH...LIVERPOOL...BONNEY...LA WARD
  AND QUINTANA.

LAT...LON 2927 9666 2929 9563 2949 9532 2908 9513
      2887 9538 2888 9539 2865 9587 2870 9576
      2871 9575 2871 9591 2863 9598 2857 9604
      2864 9598 2858 9621 2875 9618 2864 9632
      2876 9645 2873 9644 2871 9664 2906 9694

$$

The office that day

Everything else NWS Houston/Galveston, TX issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 11, 2:47 AM CDTAreal Flood AdvisoryHGXBrazoria, Matagorda118 min
Jul 11, 4:02 AM CDTFlash Flood WarningHGXBrazoria, Matagorda118 min
Jul 11, 4:21 AM CDTAreal Flood AdvisoryHGXFort Bend, Harris114 min
Jul 11, 4:41 AM CDTFlash Flood WatchHGXAustin, Brazoria, Brazos, Burleson, Chambers, Colorado and 15 more64 hr
Jul 11, 4:49 AM CDTAreal Flood AdvisoryHGXJackson, Matagorda, Wharton116 min
Jul 11, 4:56 AM CDTAreal Flood AdvisoryHGXHarris2 hr
Jul 11, 5:24 AM CDTFlash Flood WarningHGXBrazoria, Jackson, Matagorda, Wharton2 hr
Jul 11, 5:32 AM CDTAreal Flood AdvisoryHGXBrazos, Grimes, Harris, Montgomery, Waller, Washington118 min
Jul 11, 6:12 AM CDTFlash Flood WarningHGXAustin, Brazos, Grimes, Harris, Montgomery, Waller and 1 more2 hr
Jul 11, 6:29 AM CDTRiver Flood WarningHGXMatagorda, Wharton62 hr
Jul 11, 7:24 AM CDTFlash Flood WarningHGXBrazoria, Jackson, Matagorda, Wharton3 hr
Jul 11, 7:36 AM CDTAreal Flood AdvisoryHGXHarris, Montgomery114 min
Jul 11, 8:04 AM CDTFlash Flood WarningHGXAustin, Colorado, Grimes, Harris, Montgomery, Waller and 1 more3 hr
Jul 11, 12:19 PM CDTSpecial Weather StatementHGXJackson, Matagorda, Wharton41 min
Jul 11, 12:59 PM CDTFlash Flood WarningHGXBrazoria, Jackson, Matagorda, Wharton3 hr
Jul 11, 2:49 PM CDTRiver Flood WarningHGXHarris6 hr
Jul 11, 2:49 PM CDTRiver Flood WarningHGXJackson, Wharton27 hr

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.