Alert archive / Texas / Tornado Warnings in 1997

Tornado Warning 20, NWS Houston/Galveston, TX

April 11, 1997Harris County, Texas

NWS Houston/Galveston, TX issued this tornado warning at Apr 11, 1997, 6:11 PM CDT for Harris County, Texas. It was in force for 49 min. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Apr 11, 1997, 6:11 PM CDT (23:11 UTC)
Expired
Apr 11, 1997, 7:00 PM CDT
In force
49 min
Issued by
NWS Houston/Galveston, TX
Area
Whole counties

County Harris County, TX

The radar

The Houston radar (KHGX), 52 km from the middle of the area, began a volume at 23:14 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 11, 6:28 PM CDTHail 1.75Houston, TX

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Apr 11, 2:30 PM CDTTornado WatchSPC6 hr

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 11.2 hours before the alert went out and 213 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 12:00Z on 1997-04-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 723 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 12:00Z on 1997-04-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 137 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
723 J/kg
Mixed-layer CIN
-45 J/kg
Mixed-layer LCL
601 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
137 m²/s²
0-3 km storm-relative helicity
205 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.9

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KHOU 112311
TORHOU
TXC201-120000-
 
BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
611 PM CDT FRI APR 11 1997
 
THE NATIONAL WEATHER SERVICE IN HOUSTON/GALVESTON HAS ISSUED A
TORNADO WARNING EFFECTIVE UNTIL  700 PM CDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN SOUTHEAST TEXAS
 
   ...EASTERN HARRIS COUNTY
 
TORNADIC THUNDERSTORM INDICATED BY RADAR JUST WEST OF CHANNELVIEW MOVING
EAST AT 20 MPH.
 
THIS IS A DANGEROUS STORM SITUATION.  ACT QUICKLY.  IF YOU ARE
IN THE PATH OF THIS TORNADO... GO TO A SMALL INTERIOR ROOM ON
THE LOWEST FLOOR POSSIBLE.  AVOID WINDOWS.  ABANDON CARS AND
MOBILE HOMES FOR A REINFORCED BUILDING.  AS A LAST RESORT GET
INTO A DITCH OR CULVERT.

What forecasters said that day

The local office's own words before this tornado 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 tornado warning went out at Apr 11, 2:40 PM CDT, 3 hours 31 minutes earlier.

Area forecast discussion, Apr 11, 2:40 PM CDT, 3 hours 31 minutes before
SOUTHEAST TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON
TX 940 AM CDT FRI APR 11 1997

AIRMASS OVR SW SECTIONS OF FA ARE VERY MOIST AND UNSTABLE WITH SELS
REPORTING CAPES ARND 3500+.  CF NEAR CLL ATTM IS PROGD TO MV INTO
HOUSTON METRO AREA ARND 4-5 PM AND THEN OFF COAST BETWEEN 7-8 PM.
SATL WV SHOWS STRNG SPD MX PULLING UP OUT OF SW TX AND SHUD PROVIDE
KICK FOR STRNG TSTMS TO DVLP OVR SW SECTIONS AND TRAIN TO NE ACRS
RMNG FA ALONG AND JUST OUT AHEAD OF FROPA.  THEREFORE...SVR WX & HVY
RAINS STILL A THREAT LATE AFTN/EVENG FOR PORTIONS OF SE TX.  FNT SHUD
PUSH THRU CNTRL ZONES ABOUT FCST ISSUENCE TIME SO WORDING WILL BE
DIFFICULT THERE.  WATCH TILL 01Z REQUIRES CONT MENTION OF PSBL SVR
WITH HVY RAINS EARLY...THEN SHIFT WNDS AND LWR CHC TSTMS TO SLGT CHC
LGT RAIN AFTER FROPA.  SATL SHOWS DRY AIR ADVECTING UP FM SW BUT
BELIEVE POST-FNTL ST DECK WILL PREVAIL MOST OF TNGT THEN ERODE BY
MRNG AND GIVE WAY TO BKN MID LVL CLDS ON SAT.  DECREASING CLDS SAT
AFTN WILL ALLOW FAIR SKIES SAT NGT TO BOTTOM TMPS OUT INTO THE 40S.
OVRRNG CLDS SEEM TO SET UP LATE SUN AS NXT UPR TROF DIGS INTO BAJA
AREA AND SPREADS PAC MOIST/CLDS OVR A COOL DRY NE-E FLOW AT SFC.
WILL TWEAK CLDS AND TMPS ACCORDINGLY WITH NO POPS AFTR TNGT.  CAUTION
ADVISED ON AREA LAKES INLAND...INLAND BAYS AND WATERWAYS FOR COASTAL
ZONES TNGT AND SAT.  LEANING TWRD COOL DRY S ATTM.  39

PRELIMS...

CLL E/B A/B-E  48/55 42/63  2000
IAH E/B A/B-E  52/60 44/64  6-2000
GLS C/E B/B-E  58/64 55/63  8-2000

In the hours before

Special weather statement, Apr 11, 2:25 PM CDT, 3 hours 46 minutes before
TXZ178-179-199-200-210>214-226-227-235>238-511-513-120130-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
225 PM CDT FRI APR 11 1997

...A TORNADO WATCH HAS BEEN ISSUED UNTIL 800 PM FOR MOST OF
SOUTHEAST TEXAS...

THE NATIONAL WEATHER SERVICE HAS ISSUED A TORNADO WATCH UNTIL 8 PM
FOR THE SOUTHERN PORTIONS OF SOUTHEAST TEXAS.  COUNTIES IN THE
WATCH AREA INCLUDE...POLK...SAN JACINTO...MONTGOMERY...WALLER...
AUSTIN...COLORADO...LIBERTY...CHAMBERS...HARRIS...GALVESTON...
BRAZORIA...FORT BEND...MATAGORDA...WHARTON...JACKSON.

CITIES IN THE WATCH AREA INCLUDE CONROE...HOUSTON...COLUMBUS...
RICHMOND...EL CAMPO...ANGLETON...AND GALVESTON.  THE WATCH INCLUDES
THE ADJACIENT COASTAL WATERS.

SCATTERED TO NUMEROUS THUNDERSTORMS ARE DEVELOPING ACROSS THE AREA
THIS AFTERNOON IN A VERY MOIST AND UNSTABLE ATMOSPHERE. A
COMBINATION OF A STRONG UPPER LEVEL DISTURBANCE...THE JET STREAM
ALOFT...AND A STRONG COLD FRONT AT THE SURFACE HAVE INDUCED A WIND
SHEAR PATTERN FAVORABLE FOR THE DEVELOPMENT OF TORNADIC STORMS OVER
THE WATCH AREA.  THE COLD FRONT IS EXPECTED TO MOVE THROUGH THE
HOUSTON AREA BETWEEN 4 AND 6 PM...THEN OFF OF THE COAST BETWEEN 8
AND 10 PM.

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA.
PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING
WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE
WARNINGS.

AMATUER RADIO OPERATORS AND SKYWARN SPOTTERS ARE URGED TO MONITOR
THIS WEATHER SITUATION AND BE PREPARED FOR ACTIVATION.

STAY TUNED TO NOAA WEATHER RADIO FOR FURTHER UPDATES AND STATEMENTS.

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, 5:33 AM CDTFlash Flood WarningHGXGalveston3 hr
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, 6:45 PM CDTSevere Thunderstorm WarningHGXChambers60 min
Apr 11, 6:58 PM CDTSevere Thunderstorm WarningHGXHarris32 min

Nearby

Tornado Warnings in Texas, 1997Every tornado warning in 1997Tornadoes 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.