Alert archive / Louisiana / Tornado Watches in 2008

Tornado Watch 900

September 12, 200827 parishes in Louisiana; 26 counties in Texas

The Storm Prediction Center issued this tornado watch at Sep 12, 2008, 7:54 PM CDT for 27 parishes in Louisiana; 26 counties in Texas. It was in force for 14 hr.

The area

The outline as issued.

The facts

Issued
Sep 12, 2008, 7:54 PM CDT (00:54 UTC)
Expired
Sep 13, 2008, 10:00 AM CDT
In force
14 hr
Issued by
the Storm Prediction Center
Largest hail expected
0.5 in
Strongest gust expected
60 kt
All 53 counties

Acadia Parish, LA, Allen Parish, LA, Assumption Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, De Soto Parish, LA, Evangeline Parish, LA, Grant Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, LaSalle Parish, LA, Natchitoches Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Red River Parish, LA, Sabine Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Terrebonne Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, Winn Parish, LA, Angelina County, TX, Brazoria County, TX, Chambers County, TX, Cherokee County, TX, Fort Bend County, TX, Galveston County, TX, Hardin County, TX, Harris County, TX, Houston County, TX, Jasper County, TX, Jefferson County, TX, Liberty County, TX, Montgomery County, TX, Nacogdoches County, TX, Newton County, TX, Orange County, TX, Panola County, TX, Polk County, TX, Rusk County, TX, Sabine County, TX, San Augustine County, TX, San Jacinto County, TX, Shelby County, TX, Trinity County, TX, Tyler County, TX, Walker County, TX

What SPC expected

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

Two or more tornadoes
60%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
10%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
5%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
50%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Sep 12, 7:58 PM CDTTornado WarningLCHAvoyelles, Rapides32 min
Sep 12, 8:27 PM CDTTornado WarningLCHAcadia, Iberia, Lafayette, Saint Martin, St. Mary, Vermilion33 min
Sep 12, 9:23 PM CDTTornado WarningLCHAcadia, Iberia, Lafayette, Saint Landry, Saint Martin, Vermilion37 min
Sep 12, 10:03 PM CDTTornado WarningLCHAcadia, Allen, Evangeline, Lafayette, Saint Landry27 min
Sep 12, 10:41 PM CDTTornado WarningLCHAcadia, Allen, Evangeline, Iberia, Lafayette, Saint Landry and 1 more49 min
Sep 12, 11:04 PM CDTTornado WarningLCHAcadia, Jefferson Davis, Lafayette, Vermilion26 min
Sep 13, 12:06 AM CDTTornado WarningLCHRapides24 min
Sep 13, 12:07 AM CDTTornado WarningLCHAllen, Rapides, Vernon38 min
Sep 13, 1:38 AM CDTTornado WarningLCHAcadia, Cameron, Jefferson Davis, Vermilion22 min
Sep 13, 1:41 AM CDTTornado WarningLCHCalcasieu, Cameron, Jefferson Davis34 min
Sep 13, 2:01 AM CDTTornado WarningLCHCameron, Jefferson Davis, Vermilion29 min
Sep 13, 2:08 AM CDTTornado WarningLCHAcadia, Jefferson Davis, Vermilion37 min
Sep 13, 2:20 AM CDTFlash Flood WarningLCHCalcasieu6 hr
Sep 13, 2:35 AM CDTTornado WarningLCHAllen, Beauregard, Jefferson Davis14 min
Sep 13, 2:38 AM CDTTornado WarningLCHAcadia, Allen, Cameron, Evangeline, Jefferson Davis, Vermilion37 min
Sep 13, 2:55 AM CDTTornado WarningLCHAcadia, Vermilion35 min
Sep 13, 3:26 AM CDTTornado WarningLCHAcadia, Allen, Evangeline, Jefferson Davis34 min
Sep 13, 3:29 AM CDTTornado WarningLCHAcadia, Lafayette, Vermilion46 min
Sep 13, 3:38 AM CDTTornado WarningLCHAcadia, Cameron, Jefferson Davis, Vermilion37 min
Sep 13, 3:40 AM CDTFlash Flood WarningLCHHardin, Jefferson, Orange3 hr
Sep 13, 3:57 AM CDTTornado WarningLCHAllen, Beauregard, Rapides, Vernon33 min
Sep 13, 4:11 AM CDTTornado WarningLCHAcadia, Allen, Evangeline, Jefferson Davis, Rapides, Saint Landry and 1 more34 min
Sep 13, 5:05 AM CDTFlash Flood WarningHGXBrazoria, Galveston, Harris3 hr
Sep 13, 5:14 AM CDTTornado WarningLCHBeauregard, Calcasieu, Vernon46 min
Sep 13, 5:25 AM CDTTornado WarningLCHAllen, Beauregard, Calcasieu, Jefferson Davis35 min
Sep 13, 5:32 AM CDTFlash Flood WarningLCHAllen, Beauregard, Calcasieu, Cameron, Jefferson Davis, Vernon6 hr
Sep 13, 5:51 AM CDTTornado WarningLCHBeauregard, Vernon24 min
Sep 13, 5:55 AM CDTTornado WarningLCHHardin, Jasper, Newton, Tyler35 min
Sep 13, 7:16 AM CDTTornado WarningLCHAcadia, Allen, Cameron, Jefferson Davis, Vermilion29 min
Sep 13, 7:43 AM CDTTornado WarningLCHAllen, Jefferson Davis32 min
Sep 13, 7:54 AM CDTFlash Flood WarningHGXHarris3 hr
Sep 13, 8:48 AM CDTTornado WarningLCHAllen, Beauregard, Vernon27 min
Sep 13, 9:06 AM CDTFlash Flood WarningHGXChambers, Galveston, Grimes, Harris, Liberty, Montgomery and 2 more3 hr
Sep 13, 9:10 AM CDTTornado WarningLCHAllen, Rapides, Vernon35 min
Sep 13, 9:36 AM CDTTornado WarningLCHJefferson, Orange24 min
Sep 13, 9:41 AM CDTFlash Flood WarningLCHAcadia, Allen, Beauregard, Calcasieu, Cameron, Evangeline and 3 more3 hr

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 00:00Z, 0.9 hours before the alert went out and 114 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 2008-09-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 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 2008-09-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 9 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1018 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
9 m²/s²
0-3 km storm-relative helicity
160 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 13, 12:03 AM CDTMesoscale DiscussionSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 21 more87 min
Sep 13, 7:01 AM CDTMesoscale DiscussionSPCAcadia, Allen, Assumption, Avoyelles, Beauregard, Bienville and 26 more119 min
Sep 13, 9:40 AM CDTTornado WatchSPCAcadia, Allen, Avoyelles, Beauregard, Bienville, Bossier and 27 more9 hr
Sep 13, 1:34 PM CDTMesoscale DiscussionSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 49 more116 min

Nearby

Tornado Watches in Louisiana, 2008Tornado Watches in Texas, 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.