Alert archive / Texas / Tornado Watches in 1997

Tornado Watch 156

April 11, 199724 counties in Texas

The Storm Prediction Center issued this tornado watch at Apr 11, 1997, 2:30 PM CDT for 24 counties in Texas. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Apr 11, 1997, 2:30 PM CDT (19:30 UTC)
Expired: Apr 11, 1997, 8:00 PM CDT
In force: 6 hr
Issued by: the Storm Prediction Center

All 24 counties

Austin County, TX, Brazoria County, TX, Calhoun County, TX, Chambers County, TX, Colorado County, TX, Fayette County, TX, Fort Bend County, TX, Galveston County, TX, Hardin County, TX, Harris County, TX, Jackson County, TX, Jefferson County, TX, Lavaca County, TX, Liberty County, TX, Matagorda County, TX, Montgomery County, TX, Orange County, TX, Polk County, TX, San Jacinto County, TX, Tyler County, TX, Victoria County, TX, Waller County, TX, Washington County, TX, Wharton County, TX

The radar

The Houston radar (KHGX), 87 km from the middle of the area, began a volume at 19:33 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.

Warnings issued inside it

8 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Apr 11, 3:30 PM CDT	Severe Thunderstorm Warning	HGX	Harris	60 min
Apr 11, 4:25 PM CDT	Severe Thunderstorm Warning	HGX	Harris, Montgomery	65 min
Apr 11, 5:06 PM CDT	Severe Thunderstorm Warning	HGX	Liberty	64 min
Apr 11, 5:17 PM CDT	Severe Thunderstorm Warning	HGX	Harris	58 min
Apr 11, 6:11 PM CDT	Tornado Warning	HGX	Harris	49 min
Apr 11, 6:45 PM CDT	Severe Thunderstorm Warning	HGX	Chambers	60 min
Apr 11, 6:58 PM CDT	Severe Thunderstorm Warning	HGX	Harris	32 min
Apr 11, 7:38 PM CDT	Severe Thunderstorm Warning	HGX	Chambers	52 min

The nearest sounding before it

Corpus Christi, TX (KCRP), launched 12:00Z, 7.5 hours before the alert went out and 256 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 2359 J/kg
Mixed-layer CIN: -53 J/kg
Mixed-layer LCL: 484 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 150 m²/s²
0-3 km storm-relative helicity: 318 m²/s²
Significant tornado parameter: 1.7
Supercell composite: 9.7

Open this sounding in Storm Lab

The text

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

101 
WWUS9 KMKC 111857
SEL6  
MKC WW 111857
TXZ000-120100-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 156
STORM PREDICTION CENTER NORMAN OK
157 PM CDT FRI APR 11 1997

A...THE STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR

   PARTS OF SOUTHEAST TEXAS                              
   AND ADJACENT COASTAL WATERS

EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING UNTIL 800 PM CDT.

TORNADOES...LARGE HAIL...DANGEROUS LIGHTNING AND DAMAGING
THUNDERSTORM WINDS ARE POSSIBLE IN THESE AREAS.


THE TORNADO WATCH AREA IS ALONG AND 60 STATUTE MILES EITHER SIDE OF
A LINE FROM 10 MILES WEST NORTHWEST OF VICTORIA TEXAS TO 35 MILES
NORTH OF PORT ARTHUR TEXAS.

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.

B..OTHER WATCH INFORMATION.. THIS TORNADO WATCH REPLACES SEVERE
THUNDERSTORM WATCH NUMBER 154.  WATCH NUMBER 154 WILL NOT BE IN
EFFECT AFTER 230 PM CDT.
$$

C...TORNADOES AND A FEW SVR TSTMS WITH HAIL SFC AND ALF TO 2 3/4
INCHES.  EXTRM TURBC AND SFC WIND GUSTS TO 70 KNOTS.  A FEW CBS
WITH MAX TOPS TO 550.  MEAN WIND VECTOR 24025.

D...LN STG TSTMS CONT TO PUSH SEWD INTO VERY UNSTBL AMS OVR SERN
TX. CAPES IN EXCESS OF 3000 J/KG AND SFC LI/S TO MINUS 10 WRN
PORTION OF WATCH.  GOOD MSTR CNVRGNC BTWN APCHG LN AND RETREATING
OLD CNVCTV BNDY W OF HOU.  STMS SHUD RPDLY INCR TO SVR WITH CONTD
HEATING AND THEN DVLP/PROPAGATE SEWD INTO GULF THIS EVE.

E...OTR TSTMS... THIS WATCH REPLACES..WW 154.

...HALES

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 10, 8:15 PM CDT	Severe Thunderstorm Watch	SPC	Hardeman	6 hr
Apr 10, 8:45 PM CDT	Tornado Watch	SPC	Andrews, Borden, Briscoe, Castro, Childress, Coke and 36 more	6 hr
Apr 11, 3:00 AM CDT	Tornado Watch	SPC	Archer, Baylor, Brown, Callahan, Clay, Coke and 26 more	6 hr
Apr 11, 9:30 AM CDT	Severe Thunderstorm Watch	SPC	Anderson, Angelina, Bastrop, Bell, Brazos, Burleson and 28 more	6 hr

Nearby

Tornado Watches in Texas, 1997 Every tornado watch 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.