Alert archive / Louisiana / Severe Thunderstorm Watches in 2012

Severe Thunderstorm Watch 327

May 31, 201243 parishes in Louisiana; 11 counties in Mississippi; 5 counties in Texas

The Storm Prediction Center issued this severe thunderstorm watch at May 31, 2012, 10:41 AM CDT for 43 parishes in Louisiana; 11 counties in Mississippi; 5 counties in Texas. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
May 31, 2012, 10:41 AM CDT (15:41 UTC)
Expired
May 31, 2012, 4:30 PM CDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 59 counties

Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Caldwell Parish, LA, Cameron Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Baton Rouge Parish, LA, East Carroll Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Grant Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jackson Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, LaSalle Parish, LA, Livingston Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Richland Parish, LA, Sabine Parish, LA, Saint Helena Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Tensas Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, West Baton Rouge Parish, LA, West Carroll Parish, LA, West Feliciana Parish, LA, Winn Parish, LA, Adams County, MS, Amite County, MS, Claiborne County, MS, Copiah County, MS, Franklin County, MS, Issaquena County, MS, Jefferson County, MS, Lincoln County, MS, Pike County, MS, Warren County, MS, Wilkinson County, MS, Hardin County, TX, Jasper County, TX, Jefferson County, TX, Newton County, TX, Orange County, TX

What SPC expected

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

Two or more tornadoes
10%
One or more EF2 to EF5 tornadoes
5%
Ten or more severe wind reports
50%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
40%
One or more hailstones of 2 inches or more
20%
Six or more combined severe hail and wind reports
80%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
May 31, 10:49 AM CDTSevere Thunderstorm WarningLCHBeauregard41 min
May 31, 11:22 AM CDTSevere Thunderstorm WarningJANFranklin, Madison, Richland53 min
May 31, 11:23 AM CDTSevere Thunderstorm WarningLCHBeauregard, Calcasieu32 min
May 31, 11:27 AM CDTSevere Thunderstorm WarningSHVGrant, Natchitoches48 min
May 31, 11:34 AM CDTSevere Thunderstorm WarningLCHRapides, Vernon56 min
May 31, 12:02 PM CDTSevere Thunderstorm WarningLCHAllen, Evangeline, Rapides58 min
May 31, 12:20 PM CDTSevere Thunderstorm WarningSHVGrant, LaSalle, Natchitoches, Winn55 min
May 31, 12:48 PM CDTSevere Thunderstorm WarningLCHEvangeline, Saint Landry57 min
May 31, 12:58 PM CDTSevere Thunderstorm WarningLCHAvoyelles, Evangeline, Saint Landry62 min
May 31, 1:00 PM CDTSevere Thunderstorm WarningSHVCaldwell, Grant, LaSalle60 min
May 31, 1:40 PM CDTSevere Thunderstorm WarningJANCatahoula, Concordia50 min
May 31, 2:08 PM CDTSevere Thunderstorm WarningJANMadison67 min
May 31, 2:11 PM CDTSevere Thunderstorm WarningLIXEast Feliciana, Saint Helena34 min
May 31, 2:13 PM CDTSevere Thunderstorm WarningJANCatahoula, Franklin, Tensas62 min
May 31, 2:32 PM CDTSevere Thunderstorm WarningLIXAmite, Pike28 min
May 31, 2:35 PM CDTSevere Thunderstorm WarningJANFranklin, Madison, Tensas55 min
May 31, 2:50 PM CDTSevere Thunderstorm WarningLIXLivingston, Tangipahoa25 min
May 31, 2:55 PM CDTTornado WarningLIXLivingston, Saint Helena, Tangipahoa35 min
May 31, 3:06 PM CDTSevere Thunderstorm WarningJANMadison, Richland45 min
May 31, 3:23 PM CDTSevere Thunderstorm WarningJANCopiah, Hinds, Leake, Madison, Rankin, Simpson67 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, 3.7 hours before the alert went out and 175 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 2012-05-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2548 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 2012-05-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 49 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
2548 J/kg
Mixed-layer CIN
-3 J/kg
Mixed-layer LCL
650 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
49 m²/s²
0-3 km storm-relative helicity
36 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.6

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 31, 9:47 AM CDTMesoscale DiscussionSPCAcadia, Allen, Beauregard, Calcasieu, Cameron, Evangeline and 7 more58 min
May 31, 1:53 PM CDTMesoscale DiscussionSPCAscension, Assumption, East Baton Rouge, East Feliciana, Iberville, Livingston and 12 more67 min
May 31, 2:53 PM CDTSevere Thunderstorm WatchSPCJefferson, Lafourche, Orleans, Plaquemines, Saint Bernard, Saint Charles and 4 more5 hr
May 31, 11:59 AM CDTMesoscale DiscussionSPCAlcorn, Attala, Benton, Bolivar, Calhoun, Carroll and 32 more61 min
May 31, 12:59 PM CDTSevere Thunderstorm WatchSPCAlcorn, Attala, Benton, Bolivar, Calhoun, Carroll and 41 more6 hr
May 31, 2:38 PM CDTMesoscale DiscussionSPCAlcorn, Attala, Benton, Bolivar, Calhoun, Carroll and 38 more67 min
May 31, 5:30 PM CDTMesoscale DiscussionSPCPrentiss, Tishomingo2 hr
May 30, 7:37 PM CDTMesoscale DiscussionSPCBlanco, Brown, Burnet, Callahan, Coleman, Comanche and 22 more113 min
May 30, 8:38 PM CDTMesoscale DiscussionSPCArmstrong, Briscoe, Carson, Childress, Collingsworth, Cottle and 13 more97 min
May 30, 10:15 PM CDTMesoscale DiscussionSPCBlanco, Brown, Burnet, Callahan, Coleman, Comanche and 22 more2 hr
May 31, 6:02 AM CDTMesoscale DiscussionSPCBrazos, Falls, Freestone, Houston, Leon, Limestone and 5 more88 min
May 31, 6:21 PM CDTMesoscale DiscussionSPCBrewster, Jeff Davis, Pecos, Presidio, Reeves2 hr

Nearby

Severe Thunderstorm Watches in Louisiana, 2012Severe Thunderstorm Watches in Mississippi, 2012Severe Thunderstorm Watches in Texas, 2012Every severe thunderstorm watch in 2012

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.