Alert archive / Texas / Tornado Watches in 2001

Tornado Watch 772

October 11, 200141 counties in Texas

The Storm Prediction Center issued this tornado watch at Oct 11, 2001, 8:00 AM CDT for 41 counties in Texas. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Oct 11, 2001, 8:00 AM CDT (13:00 UTC)
Expired: Oct 11, 2001, 1:00 PM CDT
In force: 5 hr
Issued by: the Storm Prediction Center

All 41 counties

Anderson County, TX, Angelina County, TX, Austin County, TX, Brazoria County, TX, Brazos County, TX, Burleson County, TX, Calhoun County, TX, Chambers County, TX, Cherokee County, TX, Colorado County, TX, Fort Bend County, TX, Freestone County, TX, Galveston County, TX, Gregg County, TX, Grimes County, TX, Hardin County, TX, Harris County, TX, Harrison County, TX, Houston County, TX, Jackson County, TX, Jasper County, TX, Jefferson County, TX, Leon County, TX, Liberty County, TX, Madison County, TX, Matagorda County, TX, Montgomery County, TX, Nacogdoches County, TX, Panola County, TX, Polk County, TX, Robertson County, TX, Rusk County, TX, San Augustine County, TX, San Jacinto County, TX, Shelby County, TX, Trinity County, TX, Tyler County, TX, Walker County, TX, Waller County, TX, Washington County, TX, Wharton County, TX

The radar

The Houston radar (KHGX), 145 km from the middle of the area, began a volume at 13:02 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

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

Issued	Product	Office	Counties	Lasted
Oct 11, 8:15 AM CDT	Tornado Warning	HGX	Harris	60 min
Oct 11, 8:36 AM CDT	Tornado Warning	HGX	Montgomery, Walker	39 min
Oct 11, 9:15 AM CDT	Severe Thunderstorm Warning	HGX	Montgomery	45 min
Oct 11, 9:30 AM CDT	Severe Thunderstorm Warning	HGX	Harris	45 min
Oct 11, 10:00 AM CDT	Severe Thunderstorm Warning	HGX	Harris, Liberty, Montgomery	45 min
Oct 11, 10:22 AM CDT	Tornado Warning	LCH	Hardin	53 min
Oct 11, 10:45 AM CDT	Severe Thunderstorm Warning	HGX	Chambers, Liberty	45 min
Oct 11, 10:50 AM CDT	Tornado Warning	HGX	Brazoria	40 min
Oct 11, 11:37 AM CDT	Severe Thunderstorm Warning	LCH	Hardin, Jefferson	53 min

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 1.0 hours before the alert went out and 244 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: 1805 J/kg
Mixed-layer CIN: -4 J/kg
Mixed-layer LCL: 496 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 95 m²/s²
0-3 km storm-relative helicity: 120 m²/s²
Significant tornado parameter: 1.2
Supercell composite: 5.4

Open this sounding in Storm Lab

The text

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

235 
WWUS9 KMKC 111250
SEL2  

SEL2  
MKC WW 111247
TXZ000-111800-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 772
STORM PREDICTION CENTER NORMAN OK
747 AM CDT THU OCT 11 2001

THE STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

   EASTERN TEXAS                              

EFFECTIVE THIS THURSDAY MORNING AND AFTERNOON FROM 800 AM UNTIL 100
PM CDT.

TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS ALONG AND 115 STATUTE MILES NORTH AND
SOUTH OF A LINE FROM 70 MILES SOUTH SOUTHWEST OF COLLEGE STATION
TEXAS TO 50 MILES EAST NORTHEAST OF LUFKIN 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.


DISCUSSION...VERY MOIST AND UNSTABLE AIRMASS ERN TX AHEAD OF
APPROACHING S/WV TROUGH.  MORNING HEATING SHOULD BE SUFFICIENT TO
DEVELOP SEVERE THUNDERSTORMS AND WITH MODERATE DEEP LAYER SHEAR IN
SUCH A TROPICAL AIR MASS...ISOLATED TORNADIC SUPERCELLS ARE LIKELY.


AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES.  EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 60 KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. 
MEAN STORM MOTION VECTOR 24030.


...HALES

295,0935 275,0964 311,0964 331,0935

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Oct 11, 10:00 AM CDT	Tornado Watch	SPC	Newton	5 hr

Nearby

Tornado Watches in Texas, 2001 Every tornado watch in 2001

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.