Alert archive / Louisiana / Tornado Watches in 2006

Tornado Watch 264

April 29, 200622 parishes in Louisiana; 4 counties in Mississippi

The Storm Prediction Center issued this tornado watch at Apr 29, 2006, 5:43 PM CDT for 22 parishes in Louisiana; 4 counties in Mississippi. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Apr 29, 2006, 5:43 PM CDT (22:43 UTC)
Expired
Apr 30, 2006, 12:00 AM CDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
60 kt
All 26 counties

Ascension Parish, LA, Assumption Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Iberville Parish, LA, Jefferson Parish, LA, Lafourche Parish, LA, Livingston Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Pointe Coupee Parish, LA, Saint Bernard Parish, LA, Saint Charles Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Tammany Parish, LA, Tangipahoa Parish, LA, Terrebonne Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Amite County, MS, Pike County, MS, Walthall County, MS, Wilkinson County, MS

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
40%
One or more EF2 to EF5 tornadoes
30%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
40%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
20%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 29, 6:14 PM CDTSevere Thunderstorm WarningLIXEast Baton Rouge, Iberville, Livingston, West Baton Rouge46 min
Apr 29, 6:24 PM CDTSevere Thunderstorm WarningLIXAmite, Wilkinson66 min
Apr 29, 6:55 PM CDTSevere Thunderstorm WarningLIXEast Baton Rouge, Livingston, Saint Helena, West Baton Rouge50 min
Apr 29, 7:20 PM CDTFlash Flood WarningLIXEast Baton Rouge, Iberville, West Baton Rouge115 min
Apr 29, 7:27 PM CDTSevere Thunderstorm WarningLIXAscension, East Baton Rouge, Iberville, Livingston, Saint John the Baptist, Tangipahoa48 min
Apr 29, 7:47 PM CDTSevere Thunderstorm WarningLIXLivingston, Saint Helena, Tangipahoa58 min
Apr 29, 8:03 PM CDTSevere Thunderstorm WarningLIXAmite, Pike57 min
Apr 29, 8:13 PM CDTSevere Thunderstorm WarningLIXAscension, Livingston, Saint John the Baptist, Saint Tammany, Tangipahoa62 min
Apr 29, 8:37 PM CDTSevere Thunderstorm WarningLIXTangipahoa, Washington53 min
Apr 29, 8:50 PM CDTSevere Thunderstorm WarningLIXAscension, Assumption, Saint James, Saint John the Baptist40 min
Apr 29, 9:15 PM CDTSevere Thunderstorm WarningLIXLivingston, Saint Tammany, Tangipahoa60 min
Apr 29, 9:28 PM CDTSevere Thunderstorm WarningLIXWashington47 min
Apr 29, 10:02 PM CDTTornado WarningLIXSaint Tammany, Tangipahoa28 min
Apr 29, 10:08 PM CDTSevere Thunderstorm WarningLIXWashington52 min
Apr 29, 10:30 PM CDTTornado WarningLIXSaint Tammany30 min
Apr 29, 10:56 PM CDTSevere Thunderstorm WarningLIXSaint Tammany49 min
Apr 29, 11:50 PM CDTFlash Flood WarningLIXSaint Tammany70 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 10.7 hours before the alert went out and 112 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, Slidell Radar S, LA at 12:00Z on 2006-04-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2 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, Slidell Radar S, LA at 12:00Z on 2006-04-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 68 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
2 J/kg
Mixed-layer CIN
-3 J/kg
Mixed-layer LCL
813 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
68 m²/s²
0-3 km storm-relative helicity
177 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.

000 
WWUS20 KWNS 292228
SEL4  
SPC WW 292228
LAZ000-MSZ000-CWZ000-300500-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 264
NWS STORM PREDICTION CENTER NORMAN OK
520 PM CDT SAT APR 29 2006

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

       SOUTHEASTERN LOUISIANA
       A SMALL PART OF SOUTHWEST MISSISSIPPI
       COASTAL WATERS

EFFECTIVE THIS SATURDAY AFTERNOON FROM 520 PM UNTIL MIDNIGHT CDT.

TORNADOES...HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 55 STATUTE
MILES EAST AND WEST OF A LINE FROM 20 MILES WEST NORTHWEST OF MC
COMB MISSISSIPPI TO 30 MILES SOUTH SOUTHEAST OF HOUMA LOUISIANA. 
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU4).

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 263...

DISCUSSION...INTENSE THUNDERSTORMS WILL MAINTAIN THEIR ORGANIZATION
AS SUPERCELLS AND SMALL LINES/CLUSTERS OVERSPREAD SERN LA/SWRN MS
THIS EVENING.  VERY STRONG LOW LEVEL SHEAR ALONG WITH FAVORABLE
BOUNDARY LAYER RELATIVE HUMIDITY WILL SUPPORT LOW LEVEL ROTATION AND
THE THREATS OF DAMAGING WINDS AND TORNADOES.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 23030.


...EVANS

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 29, 6:04 AM CDTTornado WatchSPCAllen, Beauregard, Bienville, Bossier, Caddo, Calcasieu and 18 more7 hr
Apr 29, 7:37 AM CDTMesoscale DiscussionSPCAllen, Beauregard, Bienville, Bossier, Caddo, Calcasieu and 19 more83 min
Apr 29, 9:57 AM CDTMesoscale DiscussionSPCAllen, Beauregard, Bienville, Calcasieu, Grant, Jackson and 7 more2 hr
Apr 29, 11:55 AM CDTMesoscale DiscussionSPCAcadia, Allen, Avoyelles, Beauregard, Bienville, Bossier and 30 more65 min
Apr 29, 12:47 PM CDTTornado WatchSPCAcadia, Allen, Avoyelles, Beauregard, Bienville, Bossier and 27 more8 hr
Apr 29, 6:26 PM CDTMesoscale DiscussionSPCJackson, Lincoln, Ouachita, Union94 min

Nearby

Tornado Watches in Louisiana, 2006Tornado Watches in Mississippi, 2006Every tornado watch in 2006

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.