Alert archive / Texas / Tornado Watches in 2002

Tornado Watch 812

December 30, 2002De Soto Parish, Red River Parish, Sabine Parish, Louisiana; 35 counties in Texas

The Storm Prediction Center issued this tornado watch at Dec 30, 2002, 3:20 PM CST for De Soto Parish, Red River Parish, Sabine Parish, Louisiana; 35 counties in Texas. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Dec 30, 2002, 3:20 PM CST (21:20 UTC)
Expired: Dec 30, 2002, 9:00 PM CST
In force: 6 hr
Issued by: the Storm Prediction Center

All 38 counties

De Soto Parish, LA, Red River Parish, LA, Sabine Parish, LA, Anderson County, TX, Angelina County, TX, Austin County, TX, Brazoria County, TX, Brazos County, TX, Chambers County, TX, Cherokee County, TX, Colorado County, TX, Fort Bend County, TX, Galveston County, TX, Grimes County, TX, Hardin County, TX, Harris County, TX, Houston County, TX, Jasper County, TX, Lavaca County, TX, Leon County, TX, Liberty County, TX, Madison County, TX, Montgomery County, TX, Nacogdoches County, TX, Newton County, TX, Panola County, TX, Polk County, TX, Rusk County, TX, Sabine 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), 103 km from the middle of the area, began a volume at 21:21 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

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

Issued	Product	Office	Counties	Lasted
Dec 30, 5:58 PM CST	Severe Thunderstorm Warning	SHV	Rusk	62 min
Dec 30, 6:16 PM CST	Severe Thunderstorm Warning	EWX	Lavaca	44 min
Dec 30, 7:03 PM CST	Tornado Warning	HGX	Austin, Colorado	27 min
Dec 30, 7:34 PM CST	Severe Thunderstorm Warning	SHV	De Soto	56 min
Dec 30, 7:57 PM CST	Severe Thunderstorm Warning	SHV	Shelby	63 min
Dec 30, 8:18 PM CST	Severe Thunderstorm Warning	SHV	Bienville, Claiborne, Red River, Webster	57 min
Dec 30, 8:28 PM CST	Severe Thunderstorm Warning	SHV	Sabine	92 min

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 9.3 hours before the alert went out and 231 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: 4 J/kg
Mixed-layer CIN: -18 J/kg
Mixed-layer LCL: 734 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 205 m²/s²
0-3 km storm-relative helicity: 219 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

130 
WWUS20 KWNS 302118
SEL2  
SPC WW 302120
LAZ000-TXZ000-CWZ000-310300-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 812
STORM PREDICTION CENTER NORMAN OK
320 PM CST MON DEC 30 2002

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

   FAR WEST LOUISIANA                          
   SOUTHEAST TEXAS                              
   COASTAL WATERS                     

EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 320 PM UNTIL 900
PM CST.

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 80 STATUTE MILES EAST AND WEST
OF A LINE FROM 65 MILES SOUTHWEST OF HOUSTON TEXAS TO 75 MILES
NORTH 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.

OTHER WATCH INFORMATION...  CONTINUE...WW 808...WW 809...WW
810...WW 811...

DISCUSSION...SEVERE THUNDERSTORMS CURRENTLY OVER CENTRAL TX WILL
CONTINUE EWD...AND POSSIBLY EVOLVE INTO A LARGER SQUALL LINE...
INTO SERN TX THROUGH THE EVENING.  THIS WILL INCREASE THE DAMAGING
WINDS THREAT...HOWEVER STRONG LOW LEVEL SHEAR WILL ALSO MAINTAIN A
TORNADO THREAT BOTH AHEAD OF AND WITHIN EXPECTED LINE OF STORMS.


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 500. 
MEAN STORM MOTION VECTOR 24040.


...EVANS

285,0972 321,0953 321,0925 285,0944

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 30, 10:55 AM CST	Severe Thunderstorm Watch	SPC	Bosque, Collin, Comanche, Cooke, Coryell, Dallas and 25 more	5 hr
Dec 30, 12:00 PM CST	Tornado Watch	SPC	Atascosa, Bandera, Bastrop, Bexar, Blanco, Burnet and 21 more	6 hr
Dec 30, 1:30 PM CST	Tornado Watch	SPC	Anderson, Bell, Bosque, Camp, Collin, Cooke and 33 more	6 hr
Dec 30, 2:50 PM CST	Tornado Watch	SPC	Aransas, Bee, Calhoun, Duval, Goliad, Jim Wells and 9 more	6 hr
Dec 30, 4:35 PM CST	Severe Thunderstorm Watch	SPC	Brooks, Cameron, Hidalgo, Jim Hogg, Kenedy, Starr and 2 more	5 hr

Nearby

Tornado Watches in Texas, 2002 Tornado Watches in Louisiana, 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.