Alert archive / Louisiana / Tornado Watches in 2008

Tornado Watch 898

September 12, 200838 parishes in Louisiana; 4 counties in Mississippi

The Storm Prediction Center issued this tornado watch at Sep 12, 2008, 12:46 PM CDT for 38 parishes in Louisiana; 4 counties in Mississippi. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Sep 12, 2008, 12:46 PM CDT (17:46 UTC)
Expired
Sep 12, 2008, 7:54 PM CDT
In force
7 hr
Issued by
the Storm Prediction Center
All 42 counties

Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Jefferson Parish, LA, Lafayette Parish, LA, Lafourche Parish, LA, Livingston Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Pointe Coupee Parish, LA, Rapides 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 Landry Parish, LA, Saint Martin Parish, LA, Saint Tammany Parish, LA, St. Mary Parish, LA, Tangipahoa Parish, LA, Terrebonne Parish, LA, Vermilion Parish, LA, Vernon 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

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Sep 12, 1:35 PM CDTFlash Flood WarningLIXPlaquemines6 hr
Sep 12, 4:38 PM CDTTornado WarningLCHAllen, Evangeline, Rapides, Vernon37 min
Sep 12, 4:38 PM CDTTornado WarningLCHAcadia, Allen, Jefferson Davis, Vermilion37 min
Sep 12, 4:39 PM CDTTornado WarningLCHAcadia, Cameron, Jefferson Davis, Vermilion36 min
Sep 12, 5:16 PM CDTTornado WarningLCHIberia, Lafayette, Saint Martin, St. Mary, Vermilion29 min
Sep 12, 5:25 PM CDTTornado WarningLCHVernon35 min
Sep 12, 5:38 PM CDTTornado WarningLCHAcadia, Evangeline, Lafayette, Saint Landry, Saint Martin, Vermilion37 min
Sep 12, 5:48 PM CDTTornado WarningLCHIberia, Lafayette, Saint Martin, St. Mary, Vermilion27 min
Sep 12, 5:55 PM CDTTornado WarningLCHIberia, Saint Martin, St. Mary35 min
Sep 12, 6:24 PM CDTTornado WarningLCHAcadia, Evangeline, Lafayette, Saint Landry, Saint Martin36 min
Sep 12, 6:36 PM CDTTornado WarningLCHSaint Landry, Saint Martin24 min
Sep 12, 6:45 PM CDTTornado WarningLCHAllen, Evangeline, Rapides, Vernon30 min
Sep 12, 7:07 PM CDTTornado WarningLCHAvoyelles, Evangeline, Rapides, Saint Landry23 min
Sep 12, 7:21 PM CDTTornado WarningLCHRapides, Vernon24 min
Sep 12, 7:32 PM CDTTornado WarningLCHAvoyelles, Evangeline, Rapides28 min
Sep 12, 7:46 PM CDTTornado WarningLCHRapides, Vernon29 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

Lake Charles Mun, LA (KLCH), launched 12:00Z, 5.8 hours before the alert went out and 118 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 12:00Z on 2008-09-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 122 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 12:00Z on 2008-09-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 171 square meters per square second.19395878Sfc1 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
122 J/kg
Mixed-layer CIN
-186 J/kg
Mixed-layer LCL
662 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
171 m²/s²
0-3 km storm-relative helicity
220 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 11, 11:37 PM CDTMesoscale DiscussionSPCAscension, Assumption, East Baton Rouge, Iberia, Iberville, Jefferson and 15 more98 min
Sep 12, 3:52 AM CDTTornado WatchSPCAcadia, Ascension, Assumption, Avoyelles, East Baton Rouge, East Feliciana and 26 more9 hr
Sep 12, 11:48 AM CDTMesoscale DiscussionSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 39 more87 min
Sep 12, 5:55 PM CDTMesoscale DiscussionSPCAcadia, Allen, Assumption, Avoyelles, Beauregard, Calcasieu and 22 more2 hr

Nearby

Tornado Watches in Louisiana, 2008Tornado Watches in Mississippi, 2008Every tornado watch in 2008

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.