Alert archive / Louisiana / Tornado Watches in 2002

Tornado Watch 814

December 30, 200230 parishes in Louisiana; 8 counties in Texas

The Storm Prediction Center issued this tornado watch at Dec 30, 2002, 8:55 PM CST for 30 parishes in Louisiana; 8 counties in Texas. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Dec 30, 2002, 8:55 PM CST (02:55 UTC)
Expired
Dec 31, 2002, 2:00 AM CST
In force
5 hr
Issued by
the Storm Prediction Center
All 38 counties

Acadia Parish, LA, Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Bienville Parish, LA, Calcasieu Parish, LA, Caldwell Parish, LA, Cameron Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Madison Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Rapides Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Saint Landry Parish, LA, Tensas Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, Winn Parish, LA, Chambers County, TX, Galveston County, TX, Hardin County, TX, Jasper County, TX, Jefferson County, TX, Newton County, TX, Orange County, TX, Sabine County, TX

The radar

The Lake Charles radar (KLCH), 44 km from the middle of the area, began a volume at 02:55 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.

IssuedProductOfficeCountiesLasted
Dec 30, 9:02 PM CSTSevere Thunderstorm WarningSHVNatchitoches58 min
Dec 30, 9:21 PM CSTTornado WarningHGXGalveston, Harris39 min
Dec 30, 9:26 PM CSTSevere Thunderstorm WarningSHVJackson, Lincoln49 min
Dec 30, 9:36 PM CSTTornado WarningLCHJasper24 min
Dec 30, 9:39 PM CSTSevere Thunderstorm WarningSHVWinn51 min
Dec 30, 10:06 PM CSTSevere Thunderstorm WarningSHVGrant54 min
Dec 30, 10:06 PM CSTSevere Thunderstorm WarningLCHJefferson54 min
Dec 30, 10:14 PM CSTSevere Thunderstorm WarningSHVCaldwell, Ouachita, Union61 min
Dec 30, 10:26 PM CSTSevere Thunderstorm WarningSHVLaSalle64 min
Dec 30, 10:49 PM CSTSevere Thunderstorm WarningLCHOrange26 min
Dec 30, 10:56 PM CSTSevere Thunderstorm WarningJANCatahoula, Franklin59 min
Dec 30, 11:11 PM CSTSevere Thunderstorm WarningLCHCalcasieu, Cameron64 min
Dec 30, 11:43 PM CSTTornado WarningLCHCalcasieu62 min
Dec 30, 11:50 PM CSTTornado WarningLCHJefferson Davis25 min
Dec 31, 12:22 AM CSTSevere Thunderstorm WarningLCHAcadia23 min
Dec 31, 12:37 AM CSTSevere Thunderstorm WarningLCHVermilion53 min
Dec 31, 12:45 AM CSTSevere Thunderstorm WarningLCHLafayette60 min
Dec 31, 12:47 AM CSTSevere Thunderstorm WarningLCHSaint Landry28 min

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 00:00Z, 2.9 hours before the alert went out and 45 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, Lake Charles Mun, LA at 00:00Z on 2002-12-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 631 joules per kilogram.LCLLFCEL10008507005003002001001 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, Lake Charles Mun, LA at 00:00Z on 2002-12-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 198 square meters per square second.1939587897Sfc1 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
631 J/kg
Mixed-layer CIN
-9 J/kg
Mixed-layer LCL
594 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
198 m²/s²
0-3 km storm-relative helicity
233 m²/s²
Significant tornado parameter
0.5
Supercell composite
3.3

Open this sounding in Storm Lab

The text

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

000 
WWUS20 KWNS 310255
SEL4  
SPC WW 310255
LAZ000-TXZ000-CWZ000-310800-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 814
STORM PREDICTION CENTER NORMAN OK
855 PM CST MON DEC 30 2002

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

WESTERN AND CENTRAL LOUISIANA                          
EXTREME SOUTHEAST TEXAS                              
ADJACENT COASTAL WATERS                     

EFFECTIVE THIS MONDAY NIGHT AND TUESDAY MORNING FROM 855 PM UNTIL
200 AM CST.

TORNADOES...HAIL TO 1 INCH IN DIAMETER...THUNDERSTORM WIND GUSTS TO
70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS ALONG AND 75 STATUTE MILES EAST AND WEST
OF A LINE FROM 55 MILES EAST SOUTHEAST OF GALVESTON TEXAS TO 10
MILES NORTH NORTHWEST OF MONROE LOUISIANA.

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 812.  WATCH NUMBER 812 WILL NOT BE IN EFFECT AFTER 855 PM
CST.

DISCUSSION...EXTENSIVE N-S BAND OF STORMS WILL SPREAD EWD ACROSS
LA/SE TX AS A SURFACE LOW NEAR HOU DEVELOPS EWD IN ADVANCE OF A
STRONG MID LEVEL TROUGH OVER S TX.  THOUGH SBCAPE VALUES ARE NOT
EXPECTED TO EXCEED 500-1000 J/KG...STRONG LOW-LEVEL SHEAR AND MOIST
PROFILES SHOULD SUPPORT A CONTINUED THREAT OF ORGANIZED SEVERE
STORMS.  A COUPLE OF TORNADOES WILL BE POSSIBLE WITH THE MORE
DISCRETE STORMS WITHIN AND E OF THE LINE...OTHERWISE DAMAGING WINDS
SHOULD BE THE MAIN THREAT.


AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1 INCH...EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 60 KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. 
MEAN STORM MOTION VECTOR 27030.


...THOMPSON

323,0904 290,0924 290,0950 323,0932

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 31, 12:00 AM CSTSevere Thunderstorm WatchSPCAscension, Assumption, East Baton Rouge, East Feliciana, Iberia, Iberville and 18 more5 hr
Dec 31, 2:50 AM CSTTornado WatchSPCJefferson, Lafourche, Orleans, Plaquemines, Saint Bernard, Saint Charles and 1 more5 hr

Nearby

Tornado Watches in Louisiana, 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.