Alert archive / Louisiana / Tornado Watches in 2005

Tornado Watch 809

September 23, 2005Baldwin County, Mobile County, Alabama; 23 parishes in Louisiana; 6 counties in Mississippi

The Storm Prediction Center issued this tornado watch at Sep 23, 2005, 9:55 AM CDT for Baldwin County, Mobile County, Alabama; 23 parishes in Louisiana; 6 counties in Mississippi. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Sep 23, 2005, 9:55 AM CDT (14:55 UTC)
Expired
Sep 23, 2005, 5:06 PM CDT
In force
7 hr
Issued by
the Storm Prediction Center
All 31 counties

Baldwin County, AL, Mobile County, AL, Acadia Parish, LA, Ascension Parish, LA, Assumption Parish, LA, East Baton Rouge Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Parish, LA, Lafayette Parish, LA, Lafourche Parish, LA, Livingston Parish, LA, Orleans Parish, LA, Saint Bernard Parish, LA, Saint Charles Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Martin Parish, LA, Saint Tammany Parish, LA, St. Mary Parish, LA, Tangipahoa Parish, LA, Terrebonne Parish, LA, Vermilion Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, George County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Pearl River County, MS, Stone County, MS

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Sep 23, 10:00 AM CDTTornado WarningLIXAscension, Saint Charles, Saint James, Saint John the Baptist30 min
Sep 23, 10:34 AM CDTTornado WarningLIXAscension, Iberville, Saint James26 min
Sep 23, 10:39 AM CDTTornado WarningLIXAssumption, Lafourche, Saint James36 min
Sep 23, 10:44 AM CDTTornado WarningLIXSaint Charles, Saint James, Saint John the Baptist31 min
Sep 23, 11:11 AM CDTTornado WarningLIXOrleans19 min
Sep 23, 11:17 AM CDTTornado WarningLIXTerrebonne28 min
Sep 23, 11:54 AM CDTTornado WarningLIXAscension, East Baton Rouge, Iberville, Livingston, Saint John the Baptist36 min
Sep 23, 12:06 PM CDTTornado WarningLIXHancock, Harrison24 min
Sep 23, 1:00 PM CDTTornado WarningLIXJefferson, Orleans, Plaquemines, Saint Charles30 min
Sep 23, 1:24 PM CDTTornado WarningLIXEast Baton Rouge, Livingston36 min
Sep 23, 1:26 PM CDTTornado WarningLIXAscension, Livingston34 min
Sep 23, 2:09 PM CDTTornado WarningLIXAssumption, Lafourche, Saint James, Terrebonne36 min
Sep 23, 2:21 PM CDTTornado WarningLIXSaint Tammany24 min
Sep 23, 2:26 PM CDTTornado WarningLIXHancock34 min
Sep 23, 2:27 PM CDTTornado WarningLIXHarrison, Pearl River33 min
Sep 23, 2:54 PM CDTSevere Thunderstorm WarningMOBMobile66 min
Sep 23, 3:14 PM CDTTornado WarningLIXHancock16 min
Sep 23, 3:33 PM CDTTornado WarningLIXLafourche, Saint James27 min
Sep 23, 4:42 PM CDTTornado WarningLIXLivingston, Tangipahoa33 min
Sep 23, 4:51 PM CDTTornado WarningLCHAcadia24 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, 2.9 hours before the alert went out and 96 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 2005-09-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 377 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, Slidell Radar S, LA at 12:00Z on 2005-09-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 268 square meters per square second.193958Sfc1 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
377 J/kg
Mixed-layer CIN
-53 J/kg
Mixed-layer LCL
686 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
268 m²/s²
0-3 km storm-relative helicity
298 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 231500
SEL9  
SPC WW 231500
ALZ000-LAZ000-MSZ000-CWZ000-232300-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 809
NWS STORM PREDICTION CENTER NORMAN OK
955 AM CDT FRI SEP 23 2005

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

       EXTREME SOUTHERN ALABAMA
       SOUTHERN LOUISIANA
       EXTREME SOUTHERN MISSISSIPPI
       COASTAL WATERS

EFFECTIVE THIS FRIDAY MORNING AND EVENING FROM 955 AM UNTIL 600 PM
CDT.

TORNADOES...HAIL TO 0.5 INCH 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
NORTH AND SOUTH OF A LINE FROM 35 MILES WEST SOUTHWEST OF
INTRACOASTAL CITY LOUISIANA TO 35 MILES EAST SOUTHEAST OF MOBILE
ALABAMA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9).

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.

DISCUSSION...THREAT FOR MINI-SUPERCELLS AND ISOLATED TORNADOES
EXPECTED TO INCREASE THROUGH THIS AFTERNOON OVER PARTS OF THE CNTRL
GULF CST REGION AS HEATING DESTABILIZES NERN QUARTER OF CIRCULATION
OF HRCN RITA.  50 KT 0-1 KM SHEAR AND DEWPOINTS IN THE MID 70S
SUGGEST POTENTIAL ALREADY PRESENT FOR ISOLATED TORNADOES.  THREAT
MAY ALSO EXTEND E/NE ALONG LOW LEVEL CONFLUENCE BAND INTO SRN AL.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500.
MEAN STORM MOTION VECTOR 13035.


...CORFIDI

302,0924 311,0874 294,0874 284,0924

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 23, 2:12 PM CDTMesoscale DiscussionSPCBaldwin, Mobile93 min
Sep 23, 4:33 PM CDTMesoscale DiscussionSPCBaldwin, Mobile87 min
Sep 23, 5:10 PM CDTTornado WatchSPCBaldwin, Clarke, Mobile, Washington13 hr
Sep 23, 7:44 AM CDTMesoscale DiscussionSPCAscension, Assumption, Cameron, Iberville, Lafayette, Orleans and 5 more91 min

Nearby

Tornado Watches in Louisiana, 2005Tornado Watches in Mississippi, 2005Tornado Watches in Alabama, 2005Every tornado watch in 2005

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.