Alert archive / Texas / Flash Flood Warnings in 2009

Flash Flood Warning 4, NWS Austin/San Antonio, TX

April 18, 2009DeWitt County, Gonzales County, Lavaca County, Texas

NWS Austin/San Antonio, TX issued this flash flood warning at Apr 18, 2009, 11:45 AM CDT for DeWitt County, Gonzales County, Lavaca County, Texas. It was in force for 3 hr. 1 report 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
Apr 18, 2009, 11:45 AM CDT (16:45 UTC)
Expired
Apr 18, 2009, 2:45 PM CDT
In force
3 hr
Issued by
NWS Austin/San Antonio, TX
Area
Storm-based polygon
Flood severity
None

Counties DeWitt County, TX, Gonzales County, TX, Lavaca County, TX

The radar

The Austin/San Antonio radar (KEWX), 93 km from the middle of the area, began a volume at 16:47 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
Apr 18, 12:30 PM CDTHEAVY RAIN 4.276 Nne Yoakum, TX4.27 INCHES OF RAINFALL IN THE PAST 5 HOURS ALONG WITH SOME MINOR FLOODING.

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

The nearest sounding before it

Corpus Christi, TX (KCRP), launched 12:00Z, 4.8 hours before the alert went out and 175 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 2009-04-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1763 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, Corpus Christi, TX at 12:00Z on 2009-04-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 112 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
1763 J/kg
Mixed-layer CIN
-70 J/kg
Mixed-layer LCL
486 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
112 m²/s²
0-3 km storm-relative helicity
170 m²/s²
Significant tornado parameter
1.4
Supercell composite
8.4

Open this sounding in Storm Lab

The text

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

000 
WGUS54 KEWX 181645
FFWEWX
TXC123-177-285-181945-
/O.NEW.KEWX.FF.W.0004.090418T1645Z-090418T1945Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1145 AM CDT SAT APR 18 2009

THE NATIONAL WEATHER SERVICE IN AUSTIN SAN ANTONIO HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  DEWITT COUNTY...
  GONZALES COUNTY...
  LAVACA COUNTY...

* UNTIL 245 PM CDT.

* AT 1142 AM CDT...THE NATIONAL WEATHER SERVICE HAS DETERMINED THAT
  RAINFALL ESTIMATES FROM DOPPLER RADAR INDICATE FLASH FLOODING FROM
  THUNDERSTORMS OVER THE WARNED AREA. WIDESPREAD MODERATE TO HEAVY 
  RAINS CONTINUED ACROSS THE AREA. RAINFALL RATES OF 1 TO 2.5 INCHES
  PER HOUR WERE NOTED. THIS WILL PROLONG THE THREAT OF FLASH 
  FLOODING AND WILL AGGRAVATE IT IN AREAS THAT SAW HEAVY RAINS ON
  FRIDAY. 

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO WAELDER...
  SUBLIME...SHINER...PALMETO...MOULTON...HALLETTSVILLE AND GONZALES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

WHEN WATER COVERS THE ROAD...TURN AROUND DONT DROWN. THE LIFE YOU
SAVE MAY BE YOUR OWN.

&&

LAT...LON 2906 9694 2910 9698 2887 9730 2892 9743
      2937 9784 2959 9764 2975 9734 2963 9716
      2961 9685 2935 9657

$$
3 follow-up statements
000 
WGUS74 KEWX 181747
FFSEWX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1247 PM CDT SAT APR 18 2009

TXC123-177-285-181945-
/O.CON.KEWX.FF.W.0004.000000T0000Z-090418T1945Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
GONZALES TX-LAVACA TX-DEWITT TX-
1247 PM CDT SAT APR 18 2009

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 245 PM CDT FOR
DEWITT...LAVACA AND GONZALES COUNTIES...

AT 1243 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS CONTINUED TO
DETECT THUNDERSTORMS PRODUCING FLASH FLOODING OVER THE WARNED AREA. 
NUMEROUS SHOWERS AND THUNDERSTORMS WITH HEAVY RAIN CONTINUED ACROSS 
MUCH OF DE WITT AND LAVACA COUNTIES WITH RAINFALL RATES OF 2 TO 3 
INCHES PER HOUR. RAINFALL WAS SLOWLY DECREASING ACROSS GONZALES 
COUNTY WITH RAINFALL RATES LESS THAN ONE INCH PER HOUR. THIS RAIN 
WILL PROLONG THE THREAT OF FLASH FLOODING AND WILL AGGRAVATE IT IN 
AREAS THAT SAW HEAVY RAINS FRIDAY AND LAST NIGHT. 

LOCATIONS IN THE WARNING AREA INCLUDE WAELDER...SUBLIME...SHINER...
PALMETO...MOULTON...HALLETTSVILLE AND GONZALES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

WHEN WATER COVERS THE ROAD...TURN AROUND DONT DROWN. THE LIFE YOU
SAVE MAY BE YOUR OWN.

&&

LAT...LON 2906 9694 2910 9698 2887 9730 2892 9743
      2937 9784 2959 9764 2975 9734 2963 9716
      2961 9685 2935 9657

$$
000 
WGUS74 KEWX 181854
FFSEWX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
154 PM CDT SAT APR 18 2009

TXC123-177-285-181945-
/O.CON.KEWX.FF.W.0004.000000T0000Z-090418T1945Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
GONZALES TX-LAVACA TX-DEWITT TX-
154 PM CDT SAT APR 18 2009

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 245 PM CDT FOR
DEWITT...LAVACA AND GONZALES COUNTIES...

AT 150 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS CONTINUED TO 
DETECT THUNDERSTORMS PRODUCING FLASH FLOODING OVER THE WARNED AREA.
HEAVY RAINS WERE NOTED BETWEEN YOAKUM...HALLETTSVILLE AND SPEAKS 
WITH RAINFALL RATES OF 2 TO 3 INCHES PER HOUR. ELSEWHERE...PATCHY 
LIGHT RAIN WITH RAINFALL RATES LESS THAN ONE TENTH INCH PER HOUR WAS 
NOTED. THESE RAINS WILL CONTINUE TO AGGRAVATE THE FLOOD SITUATION.  

LOCATIONS IN THE WARNING AREA INCLUDE WAELDER...SUBLIME...SHINER...
PALMETO...MOULTON...HALLETTSVILLE AND GONZALES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

WHEN WATER COVERS THE ROAD...TURN AROUND DONT DROWN. THE LIFE YOU
SAVE MAY BE YOUR OWN.

&&

LAT...LON 2906 9694 2910 9698 2887 9730 2892 9743
      2937 9784 2959 9764 2975 9734 2963 9716
      2961 9685 2935 9657

$$
000 
WGUS74 KEWX 181948
FFSEWX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
248 PM CDT SAT APR 18 2009

TXC123-177-285-181956-
/O.EXP.KEWX.FF.W.0004.000000T0000Z-090418T1945Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
GONZALES TX-LAVACA TX-DEWITT TX-
248 PM CDT SAT APR 18 2009

...THE FLASH FLOOD WARNING HAS EXPIRED FOR DEWITT...LAVACA AND
GONZALES COUNTIES...

AT 245 PM CDT...ONLY LIGHT RAIN WAS NOTED ACROSS THE AREA. THE 
THREAT FOR NEW FLASH FLOODING HAS ENDED. AS A RESULT...THEN WARNING 
WAS ALLOWED TO EXPIRE. HOWEVER...SOME STREAMS MAY CONTINUE TO SEE 
RISES AND PONDING OF WATER IN LOW LYING AREAS CAN BE EXPECTED FOR 
THE NEXT HOUR OR SO. 

LAT...LON 2906 9694 2910 9698 2887 9730 2892 9743
      2937 9784 2959 9764 2975 9734 2963 9716
      2961 9685 2935 9657

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 17, 9:20 PM CDTFlash Flood WatchEWXAtascosa, Bastrop, Bexar, Caldwell, Comal, DeWitt and 10 more19 hr
Apr 18, 3:03 AM CDTSevere Thunderstorm WarningEWXVal Verde27 min
Apr 18, 3:45 AM CDTSevere Thunderstorm WarningEWXUvalde, Zavala60 min
Apr 18, 4:57 AM CDTAreal Flood AdvisoryEWXFrio, Medina, Uvalde, Zavala2 hr
Apr 18, 5:11 AM CDTAreal Flood AdvisoryEWXAtascosa, Caldwell, Gonzales, Guadalupe, Wilson2 hr
Apr 18, 5:46 AM CDTAreal Flood AdvisoryEWXBexar119 min
Apr 18, 5:49 AM CDTSevere Thunderstorm WarningEWXDimmit56 min
Apr 18, 6:45 AM CDTFlash Flood WarningEWXBastrop, Bexar, Caldwell, Fayette, Gonzales, Guadalupe and 2 more4 hr
Apr 18, 7:47 AM CDTFlash Flood WarningEWXDeWitt, Fayette, Gonzales, Karnes, Lavaca, Lee and 1 more4 hr
Apr 18, 8:44 AM CDTSevere Thunderstorm WarningEWXDeWitt, Lavaca29 min
Apr 18, 10:50 AM CDTAreal Flood AdvisoryEWXAtascosa, Bastrop, Caldwell, Fayette, Gonzales, Guadalupe and 1 more115 min
Apr 18, 12:01 PM CDTRiver Flood WarningEWXCaldwell, Gonzales24 hr
Apr 18, 4:13 PM CDTRiver Flood WarningEWXDeWitt60 hr

Nearby

Flash Flood Warnings in Texas, 2009Every flash flood warning in 2009

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.