Alert archive / Texas / Tornado Watches in 2001

Tornado Watch 781

October 12, 200120 counties in Texas

The Storm Prediction Center issued this tornado watch at Oct 12, 2001, 9:30 PM CDT for 20 counties in Texas. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Oct 12, 2001, 9:30 PM CDT (02:30 UTC)
Expired: Oct 13, 2001, 3:00 AM CDT
In force: 6 hr
Issued by: the Storm Prediction Center

Counties Atascosa County, TX, Bastrop County, TX, Bexar County, TX, Blanco County, TX, Brazos County, TX, Burleson County, TX, Caldwell County, TX, Comal County, TX, DeWitt County, TX, Fayette County, TX, Frio County, TX, Gonzales County, TX, Guadalupe County, TX, Hays County, TX, Karnes County, TX, Lee County, TX, Milam County, TX, Travis County, TX, Williamson County, TX, Wilson County, TX

The radar

The Austin/San Antonio radar (KEWX), 21 km from the middle of the area, began a volume at 02:39 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

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

Issued	Product	Office	Counties	Lasted
Oct 12, 9:56 PM CDT	Tornado Warning	EWX	Blanco, Gillespie	64 min
Oct 12, 10:27 PM CDT	Severe Thunderstorm Warning	EWX	Hays, Travis	63 min
Oct 12, 10:49 PM CDT	Severe Thunderstorm Warning	EWX	Bexar	71 min
Oct 12, 11:11 PM CDT	Severe Thunderstorm Warning	EWX	Comal	49 min
Oct 12, 11:16 PM CDT	Severe Thunderstorm Warning	EWX	Williamson	59 min
Oct 12, 11:25 PM CDT	Severe Thunderstorm Warning	EWX	Caldwell, Guadalupe	65 min
Oct 12, 11:25 PM CDT	Severe Thunderstorm Warning	EWX	Bastrop	65 min
Oct 12, 11:31 PM CDT	Severe Thunderstorm Warning	FWD	Milam	59 min
Oct 12, 11:58 PM CDT	Severe Thunderstorm Warning	EWX	Bexar, Comal	62 min
Oct 13, 12:18 AM CDT	Severe Thunderstorm Warning	HGX	Burleson	57 min
Oct 13, 12:36 AM CDT	Severe Thunderstorm Warning	HGX	Brazos, Washington	54 min

The nearest sounding before it

Corpus Christi, TX (KCRP), launched 00:00Z, 2.5 hours before the alert went out and 214 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: 3505 J/kg
Mixed-layer CIN: -15 J/kg
Mixed-layer LCL: 755 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 117 m²/s²
0-3 km storm-relative helicity: 164 m²/s²
Significant tornado parameter: 2.8
Supercell composite: 13.4

Open this sounding in Storm Lab

The text

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

281 
WWUS9 KMKC 130208
SEL1  

SEL1  
MKC WW 130203
TXZ000-130800-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 781
STORM PREDICTION CENTER NORMAN OK
903 PM CDT FRI OCT 12 2001

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

   SOUTH CENTRAL AND SOUTHEAST TEXAS                              

EFFECTIVE THIS FRIDAY NIGHT AND SATURDAY MORNING FROM 930 PM UNTIL
300 AM CDT.

TORNADOES...HAIL TO 3 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS ALONG AND 60 STATUTE MILES EAST AND WEST
OF A LINE FROM 60 MILES SOUTH OF SAN ANTONIO TEXAS TO 45 MILES WEST
NORTHWEST OF COLLEGE STATION 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.

OTHER WATCH INFORMATION...  CONTINUE...WW 777...WW 778...WW
779...WW 780...

DISCUSSION...SEVERE STORMS MOVING INTO SOUTH CENTRAL TX ARE
EXPECTED TO SPREAD EWD TONIGHT IN ADVANCE OF VIGOROUS UPPER TROUGH
DIGGING ACROSS WRN TX.  AIR MASS OVER THIS REGION IS VERY MOIST
WITH SURFACE DEW POINTS IN THE 70S...CONTRIBUTING TO MODERATE
INSTABILITY WITH SBCAPE OF 2500-3500 J/KG.  INCREASING LOW LEVEL
SHEAR ASSOCIATED WITH INTENSIFYING LOW LEVEL JET WILL ENHANCE
SEVERE THREAT INCLUDING POTENTIAL FOR SUPERCELLS AND A FEW
TORNADOES.


AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 3 INCHES.  EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 60 KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. 
MEAN STORM MOTION VECTOR 23035.


...WEISS

304,0960 283,0972 283,0992 304,0980

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Oct 12, 8:45 PM CDT	Tornado Watch	SPC	Anderson, Bell, Camp, Collin, Dallas, Delta and 23 more	6 hr
Oct 12, 11:30 PM CDT	Tornado Watch	SPC	Bowie, Camp, Cass, Gregg, Harrison, Marion and 4 more	6 hr
Oct 13, 12:30 AM CDT	Tornado Watch	SPC	Angelina, Austin, Chambers, Cherokee, Colorado, Fort Bend and 25 more	5 hr
Oct 13, 4:00 AM CDT	Tornado Watch	SPC	Chambers, Hardin, Jasper, Jefferson, Newton, Orange and 3 more	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.