Alert archive / Texas / Tornado Watches in 2002

Tornado Watch 798

December 23, 200235 counties in Texas

The Storm Prediction Center issued this tornado watch at Dec 23, 2002, 9:45 AM CST for 35 counties in Texas. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Dec 23, 2002, 9:45 AM CST (15:45 UTC)
Expired: Dec 23, 2002, 3:00 PM CST
In force: 5 hr
Issued by: the Storm Prediction Center

All 35 counties

Angelina County, TX, Austin County, TX, Bastrop County, TX, Brazoria County, TX, Brazos County, TX, Burleson County, TX, Chambers County, TX, Colorado County, TX, Fayette County, TX, Fort Bend County, TX, Grimes County, TX, Hardin County, TX, Harris County, TX, Jackson County, TX, Jasper County, TX, Jefferson County, TX, Lavaca County, TX, Lee County, TX, Liberty County, TX, Madison County, TX, Milam County, TX, Montgomery County, TX, Newton County, TX, Orange County, TX, Polk County, TX, Sabine County, TX, San Augustine County, TX, San Jacinto County, TX, Trinity County, TX, Tyler County, TX, Victoria County, TX, Walker County, TX, Waller County, TX, Washington County, TX, Wharton County, TX

The radar

The Houston radar (KHGX), 121 km from the middle of the area, began a volume at 15:49 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

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

Issued	Product	Office	Counties	Lasted
Dec 23, 9:57 AM CST	Tornado Warning	HGX	Austin	33 min
Dec 23, 10:06 AM CST	Tornado Warning	HGX	Walker	39 min
Dec 23, 10:51 AM CST	Tornado Warning	HGX	Trinity	39 min
Dec 23, 11:16 AM CST	Tornado Warning	HGX	Brazos, Grimes	44 min
Dec 23, 11:58 AM CST	Tornado Warning	HGX	Grimes, Walker	47 min
Dec 23, 12:13 PM CST	Tornado Warning	HGX	Madison	47 min
Dec 23, 1:13 PM CST	Tornado Warning	HGX	Houston, Trinity	47 min
Dec 23, 1:14 PM CST	Tornado Warning	HGX	Montgomery	46 min
Dec 23, 1:32 PM CST	Tornado Warning	HGX	San Jacinto	43 min
Dec 23, 1:54 PM CST	Tornado Warning	HGX	Harris	36 min
Dec 23, 2:07 PM CST	Tornado Warning	HGX	Montgomery	38 min
Dec 23, 2:13 PM CST	Tornado Warning	HGX	Grimes, Montgomery, Walker	47 min
Dec 23, 2:21 PM CST	Tornado Warning	HGX	Harris	39 min
Dec 23, 2:21 PM CST	Tornado Warning	HGX	Polk	54 min
Dec 23, 2:41 PM CST	Tornado Warning	HGX	Montgomery	34 min
Dec 23, 2:49 PM CST	Tornado Warning	HGX	Trinity	26 min
Dec 23, 2:54 PM CST	Tornado Warning	HGX	Walker	36 min
Dec 23, 3:00 PM CST	Tornado Warning	HGX	San Jacinto	45 min

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 3.8 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: 51 J/kg
Mixed-layer CIN: -51 J/kg
Mixed-layer LCL: 489 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 96 m²/s²
0-3 km storm-relative helicity: 193 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.1

Open this sounding in Storm Lab

The text

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

000 
WWUS20 KWNS 231543
SEL8  
WWUS20 KWNS 231545
SPC WW 231545
TXZ000-CWZ000-232100-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 798
STORM PREDICTION CENTER NORMAN OK
945 AM CST MON DEC 23 2002

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

   CENTRAL AND SOUTHEAST TEXAS                              
   COASTAL WATERS                     

EFFECTIVE THIS MONDAY MORNING AND AFTERNOON FROM 945 AM UNTIL 300
PM CST.

 ...THIS IS A PARTICULARLY DANGEROUS SITUATION...
 
DAMAGING TORNADOES...LARGE HAIL TO 2 INCHES IN DIAMETER...
THUNDERSTORM WIND GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE
POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS ALONG AND 75 STATUTE MILES NORTH AND
SOUTH OF A LINE FROM 65 MILES NORTH NORTHWEST OF VICTORIA TEXAS TO
55 MILES NORTH NORTHEAST 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.

OTHER WATCH INFORMATION...THIS TORNADO WATCH REPLACES TORNADO WATCH
NUMBER 797.  WATCH NUMBER 797 WILL NOT BE IN EFFECT AFTER 945 AM
CST.

DISCUSSION...VIGOROUS UPPER SYSTEM AND ASSOCIATED JET APPROACHING
TX FROM NRN MX. AIRMASS ACROSS TX S OF WARM FRONT VERY MOIST AND
UNSTABLE AND WITH STRONG DEEP LAYER SHEAR SUPPORTIVE OF TORNADIC
SUPERCELLS.  CURRENT SUPERCELLS WRN PORTION OF WW WILL CONTINUE
ENEWD WITH NEW DEVELOPMENT DURING EARLY AFTERNOON VICINITY WARM
WARM SERN TX.


AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES.  EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 70 KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. 
MEAN STORM MOTION VECTOR 24035.


...HALES

293,0934 283,0971 304,0971 314,0934

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 23, 5:00 AM CST	Tornado Watch	SPC	Atascosa, Austin, Bastrop, Bee, Bexar, Brazos and 37 more	5 hr
Dec 23, 2:10 PM CST	Tornado Watch	SPC	Angelina, Austin, Bastrop, Brazos, Burleson, Chambers and 31 more	6 hr
Dec 23, 3:35 PM CST	Severe Thunderstorm Watch	SPC	Atascosa, Bandera, Bastrop, Bee, Bexar, Caldwell and 22 more	4 hr

Nearby

Tornado Watches in Texas, 2002 Every tornado watch in 2002

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.