Alert archive / Louisiana / Tornado Watches in 2002

Tornado Watch 788

December 18, 20024 states

The Storm Prediction Center issued this tornado watch at Dec 18, 2002, 8:55 PM CST for 4 states. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Dec 18, 2002, 8:55 PM CST (02:55 UTC)
Expired
Dec 19, 2002, 3:00 AM CST
In force
6 hr
Issued by
the Storm Prediction Center
All 54 counties

Ashley County, AR, Bradley County, AR, Calhoun County, AR, Chicot County, AR, Cleveland County, AR, Columbia County, AR, Dallas County, AR, Desha County, AR, Drew County, AR, Lafayette County, AR, Lincoln County, AR, Nevada County, AR, Ouachita County, AR, Union County, AR, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Caldwell Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, East Carroll Parish, LA, Jackson Parish, LA, Lincoln Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Union Parish, LA, Webster Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Bolivar County, MS, Grenada County, MS, Leflore County, MS, Sunflower County, MS, Tallahatchie County, MS, Washington County, MS, Yalobusha County, MS, Anderson County, TX, Angelina County, TX, Cherokee County, TX, Gregg County, TX, Harrison County, TX, Houston County, TX, Leon County, TX, Marion County, TX, Nacogdoches County, TX, Panola County, TX, Rusk County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX

The radar

The Shreveport radar (KSHV), 16 km from the middle of the area, began a volume at 02:58 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

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

IssuedProductOfficeCountiesLasted
Dec 18, 9:06 PM CSTSevere Thunderstorm WarningSHVColumbia54 min
Dec 18, 9:14 PM CSTFlash Flood WarningSHVBossier, Caddo4 hr
Dec 18, 9:20 PM CSTFlash Flood WarningLZKCalhoun, Cleveland, Dallas, Ouachita3 hr
Dec 18, 9:21 PM CSTFlash Flood WarningSHVColumbia, Lafayette4 hr
Dec 18, 9:24 PM CSTTornado WarningLZKCleveland41 min
Dec 18, 9:37 PM CSTTornado WarningLZKCalhoun33 min
Dec 18, 9:40 PM CSTFlash Flood WarningSHVGregg, Harrison4 hr
Dec 18, 9:47 PM CSTTornado WarningLZKLincoln43 min
Dec 18, 9:52 PM CSTTornado WarningLZKBradley, Cleveland43 min
Dec 18, 10:24 PM CSTFlash Flood WarningLZKLincoln3 hr
Dec 18, 10:29 PM CSTSevere Thunderstorm WarningLZKLincoln41 min
Dec 18, 10:42 PM CSTTornado WarningLZKDesha, Lincoln43 min
Dec 18, 11:01 PM CSTFlash Flood WarningLZKBradley2 hr
Dec 18, 11:24 PM CSTSevere Thunderstorm WarningSHVUnion66 min
Dec 18, 11:45 PM CSTFlash Flood WarningLZKArkansas, Bradley, Calhoun, Cleveland, Dallas, Desha and 5 more4 hr
Dec 18, 11:50 PM CSTSevere Thunderstorm WarningSHVCherokee40 min
Dec 18, 11:55 PM CSTFlash Flood WarningLZKArkansas, Bradley, Calhoun, Cleveland, Dallas, Desha and 5 more4 hr
Dec 19, 12:00 AM CSTTornado WarningSHVUnion30 min
Dec 19, 12:19 AM CSTSevere Thunderstorm WarningSHVRusk41 min
Dec 19, 1:01 AM CSTSevere Thunderstorm WarningSHVPanola29 min
Dec 19, 1:16 AM CSTFlash Flood WarningSHVUnion4 hr
Dec 19, 2:09 AM CSTFlash Flood WarningJANBolivar4 hr
Dec 19, 2:10 AM CSTSevere Thunderstorm WarningSHVUnion35 min
Dec 19, 2:16 AM CSTSevere Thunderstorm WarningLZKDesha29 min
Dec 19, 2:37 AM CSTSevere Thunderstorm WarningJANBolivar58 min
Dec 19, 2:48 AM CSTSevere Thunderstorm WarningJANAshley47 min

The nearest sounding before it

Shreveport, LA (KSHV), launched 00:00Z, 2.9 hours before the alert went out and 16 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-pSkew-T log-p diagram, Shreveport, LA at 00:00Z on 2002-12-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1623 joules per kilogram.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Shreveport, LA at 00:00Z on 2002-12-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 291 square meters per square second.1939587897117Sfc1 km3 km6 km9 kmRMLM
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
1623 J/kg
Mixed-layer CIN
-1 J/kg
Mixed-layer LCL
618 m above ground
0-6 km bulk shear
69 kt
0-1 km storm-relative helicity
291 m²/s²
0-3 km storm-relative helicity
354 m²/s²
Significant tornado parameter
3.8
Supercell composite
12.0

Open this sounding in Storm Lab

The text

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

000 
WWUS20 KWNS 190256
SEL8  
SPC WW 190255
ARZ000-LAZ000-MSZ000-TXZ000-190900-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 788
STORM PREDICTION CENTER NORMAN OK
855 PM CST WED DEC 18 2002

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

   SOUTHERN AND EASTERN ARKANSAS                           
   NORTHERN AND WESTERN LOUISIANA                          
   WESTERN MISSISSIPPI                        
   EAST CENTRAL TEXAS                              

EFFECTIVE THIS WEDNESDAY NIGHT AND THURSDAY MORNING FROM 855 PM
UNTIL 300 AM 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 100 STATUTE MILES EAST AND WEST
OF A LINE FROM 15 MILES WEST SOUTHWEST OF LUFKIN TEXAS TO 45 MILES
NORTH OF GREENVILLE MISSISSIPPI.

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 784.  WATCH NUMBER 784 WILL NOT BE IN EFFECT AFTER 855 PM
CST.  CONTINUE...WW 785...WW 787...

DISCUSSION...SUPERCELLS EXPECTED TO CONTINUE MOVING ENE ALONG
STALLING CONVECTIVE BAND THROUGH THE OVERNIGHT HOURS.  VERY STRONG
DEEP SHEAR AND RICH GULF INFLOW SUGGEST POTENTIAL FOR A FEW
TORNADOES...ESPECIALLY OVER NRN LA AND SRN AR. 

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 450. 
MEAN STORM MOTION VECTOR 24040.

...CORFIDI

340,0891 310,0931 310,0964 340,0924

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 18, 9:05 PM CSTTornado WatchSPCCrittenden, Lee, Mississippi, Phillips, St. Francis6 hr
Dec 19, 2:25 AM CSTTornado WatchSPCAshley, Bradley, Chicot, Union8 hr
Dec 19, 12:30 AM CSTTornado WatchSPCAllen, Beauregard, Calcasieu, Evangeline7 hr
Dec 19, 6:30 AM CSTTornado WatchSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Cameron and 26 more6 hr
Dec 19, 9:35 AM CSTTornado WatchSPCJefferson, Lafourche, Orleans, Plaquemines, Saint Bernard, Saint Charles and 2 more5 hr
Dec 19, 11:40 AM CSTTornado WatchSPCAscension, Assumption, Livingston, Orleans, Saint Bernard, Saint Charles and 7 more6 hr

Nearby

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