Alert archive / Louisiana / Tornado Watches in 2007

Tornado Watch 669

September 13, 20079 parishes in Louisiana; Jefferson County, Orange County, Texas

The Storm Prediction Center issued this tornado watch at Sep 13, 2007, 3:04 AM CDT for 9 parishes in Louisiana; Jefferson County, Orange County, Texas. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Sep 13, 2007, 3:04 AM CDT (08:04 UTC)
Expired
Sep 13, 2007, 10:00 AM CDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
0.5 in
Strongest gust expected
60 kt

Counties Acadia Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Iberia Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Vermilion Parish, LA, Jefferson County, TX, Orange County, TX

The radar

The Lake Charles radar (KLCH), 10 km from the middle of the area, began a volume at 08:06 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.

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
20%
Ten or more severe wind reports
10%
One or more gusts of 65 knots or more
5%
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
20%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Sep 13, 3:33 AM CDTFlash Flood WarningLCHJefferson4 hr
Sep 13, 4:15 AM CDTTornado WarningLCHVermilion30 min
Sep 13, 4:56 AM CDTFlash Flood WarningLCHAcadia, Lafayette, Saint Landry, Vermilion4 hr
Sep 13, 6:13 AM CDTFlash Flood WarningLCHCalcasieu, Jefferson Davis4 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, 8.1 hours before the alert went out and 10 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 2007-09-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 134 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 2007-09-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 105 square meters per square second.1939Sfc1 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
134 J/kg
Mixed-layer CIN
-82 J/kg
Mixed-layer LCL
755 m above ground
0-6 km bulk shear
10 kt
0-1 km storm-relative helicity
105 m²/s²
0-3 km storm-relative helicity
106 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 12, 9:47 PM CDTMesoscale DiscussionSPCCameron88 min
Sep 13, 1:07 AM CDTMesoscale DiscussionSPCAcadia, Allen, Beauregard, Calcasieu, Cameron, Jefferson Davis and 1 more3 hr
Sep 13, 1:50 AM CDTMesoscale DiscussionSPCAcadia, Calcasieu, Cameron, Iberia, Jefferson Davis, Lafayette and 3 more115 min
Sep 13, 6:41 AM CDTMesoscale DiscussionSPCAcadia, Allen, Avoyelles, Beauregard, Evangeline, Iberia and 9 more3 hr
Sep 13, 7:13 AM CDTMesoscale DiscussionSPCAcadia, Ascension, Assumption, Iberia, Iberville, Jefferson Davis and 8 more2 hr
Sep 13, 1:56 PM CDTMesoscale DiscussionSPCAvoyelles, Catahoula, Concordia, East Baton Rouge, East Feliciana, Iberville and 4 more2 hr

Nearby

Tornado Watches in Louisiana, 2007Tornado Watches in Texas, 2007Every tornado watch in 2007

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.