Alert archive / Texas / Flash Flood Warnings in 2004

Flash Flood Warning 375, NWS Austin/San Antonio, TX

November 20, 2004Lavaca County, Texas

NWS Austin/San Antonio, TX issued this flash flood warning at Nov 20, 2004, 10:55 PM CST for Lavaca County, Texas. It was in force for 2 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
Nov 20, 2004, 10:55 PM CST (04:55 UTC)
Expired
Nov 21, 2004, 1:00 AM CST
In force
2 hr
Issued by
NWS Austin/San Antonio, TX
Area
Counties, with a storm outline in the text

County Lavaca County, TX

The radar

The Houston radar (KHGX), 134 km from the middle of the area, began a volume at 04:55 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 00:00Z, 4.9 hours before the alert went out and 210 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 00:00Z on 2004-11-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2240 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 00:00Z on 2004-11-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 168 square meters per square second.19395878Sfc1 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
2240 J/kg
Mixed-layer CIN
-12 J/kg
Mixed-layer LCL
699 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
168 m²/s²
0-3 km storm-relative helicity
172 m²/s²
Significant tornado parameter
2.0
Supercell composite
9.0

Open this sounding in Storm Lab

The text

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

000 
WGUS54 KEWX 210457
FFWEWX
TXC285-210700-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1055 PM CST SAT NOV 20 2004

THE NATIONAL WEATHER SERVICE IN AUSTIN SAN ANTONIO HAS ISSUED A

* FLASH FLOOD WARNING FOR THE FOLLOWING COUNTIES...
  LAVACA

* UNTIL 100 AM CST

* AT 1051 PM CST...NATIONAL WEATHER SERVICE DOPPLER RADAR
  INDICATED HEAVY RAINS FROM A THUNDERSTORM 5 MILES SOUTH OF
  EZZELL...OR ABOUT 16 MILES SOUTH OF HALLETTSVILLE...MOVING
  NORTHEAST AT 20 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE SPEAKS.

MANY ROADS IN LAVACA COUNTY REMAIN CLOSED FROM EARLIER FLOODING.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLASH FLOODING IS OBSERVED ACT QUICKLY. MOVE
UP TO HIGHER GROUND. DO NOT STAY IN FLOOD PRONE AREAS.

REPORT FLASH FLOODING TO THE NEAREST LAW ENFORCEMENT AGENCY FOR RELAY
TO THE NATIONAL WEATHER SERVICE.

LAT...LON 2926 9702 2910 9691 2964 9556 3003 9583

$$
2 follow-up statements
000 
WGUS74 KEWX 210601
FFSEWX
TXC285-210700-

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1159 PM CST SAT NOV 20 2004

...A FLASH FLOOD WARNING CONTINUES UNTIL 100 AM CST FOR LAVACA
COUNTY...

AT 1154 PM CST...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE HEAVY RAIN MOVING INTO LAVACA COUNTY.  RAINFALL AMOUNTS OF 
ONE HALF TO ONE INCH WAS ESTIMATED BY DOPPLER RADAR ACROSS EZZELL 
AND NORTH OF SPEAKS. ADDITIONAL SHOWERS ARE MOVING EAST INTO LAVACA 
COUNTY AT 20 MPH.

HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL CREEKS AND STREAMS...
COUNTRY ROADS...AND FARMLAND ALONG THE BANKS OF CREEKS AND STREAMS.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLASH FLOODING IS OBSERVED ACT QUICKLY. MOVE
UP TO HIGHER GROUND. DO NOT STAY IN FLOOD PRONE AREAS.

REPORT FLASH FLOODING TO THE NEAREST LAW ENFORCEMENT AGENCY FOR RELAY
TO THE NATIONAL WEATHER SERVICE.

LAT...LON 2926 9702 2910 9691 2964 9556 3003 9583

$$
000 
WGUS74 KEWX 210711
FFSEWX
TXC285-210725-

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
105 AM CST SUN NOV 21 2004

...FLASH FLOOD WARNING FOR LAVACA COUNTY HAS EXPIRED...

HEAVY RAINFALL HAS MOVED OUT OF LAVACA COUNTY. HOWEVER RUNOFF WILL
CONTINUE OVER THE NEXT COUPLE OF HOURS WHICH WILL FLOOD SMALL
CREEKS...STREAMS AND COUNTRY ROADS.

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Nov 20, 6:53 PM CSTSevere Thunderstorm WarningEWXLavaca97 min
Nov 20, 6:58 PM CSTTornado WarningEWXLavaca62 min
Nov 21, 6:53 AM CSTFlash Flood WarningEWXDeWitt, Lavaca4 hr
Nov 21, 10:38 AM CSTFlash Flood WarningEWXDeWitt, Lavaca4 hr
Nov 21, 11:45 AM CSTFlash Flood WarningEWXBexar3 hr
Nov 21, 12:15 PM CSTFlash Flood WarningEWXGonzales, Guadalupe3 hr
Nov 21, 12:43 PM CSTFlash Flood WarningEWXComal3 hr
Nov 21, 12:58 PM CSTFlash Flood WarningEWXBastrop, Caldwell3 hr
Nov 21, 1:10 PM CSTFlash Flood WarningEWXHays3 hr
Nov 21, 1:17 PM CSTSevere Thunderstorm WarningEWXBastrop58 min
Nov 21, 1:45 PM CSTFlash Flood WarningEWXBlanco, Gillespie3 hr
Nov 21, 2:05 PM CSTFlash Flood WarningEWXKarnes, Wilson3 hr
Nov 21, 2:22 PM CSTFlash Flood WarningEWXFayette, Lee3 hr
Nov 21, 2:43 PM CSTSevere Thunderstorm WarningEWXBlanco32 min
Nov 21, 2:55 PM CSTSevere Thunderstorm WarningEWXBurnet, Llano65 min
Nov 21, 3:01 PM CSTFlash Flood WarningEWXDeWitt, Lavaca3 hr
Nov 21, 3:20 PM CSTFlash Flood WarningEWXGonzales, Guadalupe3 hr
Nov 21, 4:15 PM CSTFlash Flood WarningEWXBastrop, Caldwell3 hr
Nov 21, 4:41 PM CSTFlash Flood WarningEWXFayette, Lee4 hr
Nov 21, 4:41 PM CSTFlash Flood WarningEWXKarnes4 hr
Nov 21, 5:43 PM CSTFlash Flood WarningEWXGonzales, Guadalupe, Lavaca3 hr

Nearby

Flash Flood Warnings in Texas, 2004Every flash flood warning in 2004

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.