Alert archive / Texas / Flash Flood Warnings in 1997

Flash Flood Warning 33, NWS Houston/Galveston, TX

April 11, 1997Galveston County, Texas

NWS Houston/Galveston, TX issued this flash flood warning at Apr 11, 1997, 5:33 AM CDT for Galveston County, 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 counties it named.

The facts

Issued
Apr 11, 1997, 5:33 AM CDT (10:33 UTC)
Expired
Apr 11, 1997, 8:30 AM CDT
In force
3 hr
Issued by
NWS Houston/Galveston, TX
Area
Whole counties

County Galveston County, TX

The radar

The Houston radar (KHGX), 32 km from the middle of the area, began a volume at 10:35 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

Lake Charles Mun, LA (KLCH), launched 00:00Z, 10.6 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, Lake Charles Mun, LA at 00:00Z on 1997-04-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 22 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, Lake Charles Mun, LA at 00:00Z on 1997-04-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 11 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
22 J/kg
Mixed-layer CIN
-81 J/kg
Mixed-layer LCL
946 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
11 m²/s²
0-3 km storm-relative helicity
108 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.

000 
TTAA00 KHOU 111035
FFWHOU
TXC167-111330-
 
BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
533 AM CDT FRI APR 11 1997
 
THE NATIONAL WEATHER SERVICE IN HOUSTON/GALVESTON HAS ISSUED A
FLASH FLOOD WARNING EFFECTIVE UNTIL  830 AM CDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN SOUTHEAST TEXAS
 
   ...GALVESTON COUNTY
 
AT 530 AM...A LARGE CLUSTER OF STRONG TO SEVERE THUNDERSTORMS WAS OVER
NORTHERN GALVESTON COUNTY - NORTH OF A LINE FROM HITCHCOCK TO TEXAS
CITY. THESE STORM WERE MOVING SLOWLY TO THE EAST AT 10 MPH. RADAR
ESTIMATES RAINFALL RATES OF 2 TO 3 INCHES OF RAIN PER HOUR WITH THESE
STORMS.
 
THIS IS A DANGEROUS FLOOD SITUATION.  MOST FLASH FLOOD DEATHS *OCCUR
IN AUTOMOBILES. DO NOT ATTEMPT TO CROSS BRIDGES...DIPS...OR
UNDERPASSES.  NEVER TRY TO CROSS A FLOWING STREAM...EVEN A SMALL
ONE...ON FOOT.  TO ESCAPE RISING WATER MOVE UP TO HIGHER GROUND.

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Houston/Galveston, TX wrote its last area forecast discussion before this flash flood warning went out at Apr 11, 2:46 AM CDT, 2 hours 47 minutes earlier.

Area forecast discussion, Apr 11, 2:46 AM CDT, 2 hours 47 minutes before
SOUTHEAST TEXAS FORECAST DISCUSSION ...MORE ON SECOND PAGE
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
245 AM CDT FRI APR 11 1997
...VERY DANGEROUS FLOODING SITUTATION UNDERWAY...

MCS THAT MOVED INTO THE SW ZONES SHOULD SLOW IN ITS NORTHEASTWARD
MOVEMENT AND BEGIN TO TURN MORE EAST AFTER 3 AM.  LOW LEVEL/MESOSCALE
FEATURES INDICATING THAT SIGNIFICANT TRAINING WILL BE A PROBLEM
THROUGH 12Z.  AND TO TOP IT ALL OFF IT APPEARS FROM WATER VAPOR THAT
OUTFLOW JET BECOMING PRONOUNCED ON THE WEST SIDE OF THE COMPLEX
HELPING IN THE ORGANIZATION.  RADAR ALREADY INDICATING STORM TOTAL
RAINFALL ACCUMULATIONS OF AROUND 5 INCHES NEAR EL CAMPO AND 9 TO 10
INCHES NEAR HALLETSVILLE! (SOME OF THE PRECIP OVER THESE AREAS MAY BE
GETTING SOME HAIL CONTAMINATION...ALTHOUGH SO FAR NO GROUNDTRUTH BACK
OF HAIL WITH THESE STORMS.)  ALSO OF NOTE THE VERY STRONG MESO ALONG
THE SLOW MOVING PSEUDO WARM FRONT OVER WATER.  AT THIS RATE NOT ONLY
WILL WE HAVE FLOODING PROBLEMS BUT SEVERE AS WELL.  WILL NEED TO
EXPAND FFA A LITTLE FURTHER NORTH AND MUCH FURTHER EAST AND ADD
MENTION OF SEVERE FOR A LARGE PART OF THE AREA...ALTHOUGH THE SPEED
SHEAR IS NOT TREMENDOUS THE TURNING IS IMPRESSIVE AND THE CAPE IS
RATHER APPARENT BY LOOKING AT THE REFLECTIVITY MAXIMA ALOFT A NUMBER
OF STORMS DEVELOPING STRONG MESOS OVER THE SW ZONES.

LATEST 3HR PRECIP ESTIMATES RUNNING IN EXCESS OF 7 INCHES.
...........................................................
245 AM
COMPLEX MOVING SLOWLY NORTH WITH DEVELOPMENT ALONG THE EASTERN FLANK.
WILL RUN FFA SOUTH OF A BRENHAM TO CONROE TO LIBERTY LINE.
ON DOWN THE ROAD AFTER THIS FIRST COMPLEX SHIFTS EAST THIS MORNING IT
LOOKS AS THOUGH UPPER SUPPORT REMAINS FAVORABLE FOR ANOTHER ROUND OF
THUNDERSTORMS THIS AFTERNOON SOME SEVERE AND LOCALLY HEAVY RAIN
POSSIBLE. THE FRONT WILL BE SWEEPING THE AREA OUT AND PRODUCING GUSTS
NEAR GALE OVER THE NEARSHORE WATERS AROUND 01Z.  MAY BECOME PARTLY
CLUODY BY SATURDAY AFTERNOON.

CURSORY LOOK AT NUMBERS FOLLOWS

CLL 78/47/62/46  5200
IAH 79/51/64/46  7300
GLS 77/59/66/56  8500

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 10, 10:26 PM CDTSevere Thunderstorm WarningHGXMatagorda59 min
Apr 10, 11:40 PM CDTSevere Thunderstorm WarningHGXWharton65 min
Apr 11, 12:45 AM CDTSevere Thunderstorm WarningHGXWharton60 min
Apr 11, 1:07 AM CDTFlash Flood WarningHGXWharton118 min
Apr 11, 1:40 AM CDTTornado WarningHGXWharton65 min
Apr 11, 2:04 AM CDTTornado WarningHGXFort Bend61 min
Apr 11, 2:28 AM CDTFlash Flood WarningHGXFort Bend, Wharton3 hr
Apr 11, 2:28 AM CDTTornado WarningHGXBrazoria62 min
Apr 11, 2:40 AM CDTSevere Thunderstorm WarningHGXWharton65 min
Apr 11, 2:58 AM CDTSevere Thunderstorm WarningHGXBrazoria, Fort Bend62 min
Apr 11, 3:42 AM CDTSevere Thunderstorm WarningHGXMatagorda, Wharton33 min
Apr 11, 3:59 AM CDTSevere Thunderstorm WarningHGXBrazoria61 min
Apr 11, 4:08 AM CDTFlash Flood WarningHGXBrazoria3 hr
Apr 11, 4:22 AM CDTTornado WarningHGXBrazoria, Galveston68 min
Apr 11, 5:23 AM CDTSevere Thunderstorm WarningHGXMatagorda67 min
Apr 11, 5:26 AM CDTTornado WarningHGXGalveston64 min
Apr 11, 5:27 AM CDTSevere Thunderstorm WarningHGXHarris63 min
Apr 11, 5:45 AM CDTSevere Thunderstorm WarningHGXBrazoria60 min
Apr 11, 9:24 AM CDTFlash Flood WarningHGXWharton4 hr
Apr 11, 3:30 PM CDTSevere Thunderstorm WarningHGXHarris60 min
Apr 11, 4:25 PM CDTSevere Thunderstorm WarningHGXHarris, Montgomery65 min
Apr 11, 5:06 PM CDTSevere Thunderstorm WarningHGXLiberty64 min
Apr 11, 5:17 PM CDTSevere Thunderstorm WarningHGXHarris58 min
Apr 11, 6:11 PM CDTTornado WarningHGXHarris49 min
Apr 11, 6:45 PM CDTSevere Thunderstorm WarningHGXChambers60 min
Apr 11, 6:58 PM CDTSevere Thunderstorm WarningHGXHarris32 min

Nearby

Flash Flood Warnings in Texas, 1997Every flash flood warning in 1997

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.