Alert archive / Louisiana / Mesoscale Discussions in 2005

Mesoscale Discussion 556

April 11, 20054 states

The Storm Prediction Center issued this mesoscale discussion at Apr 11, 2005, 12:12 PM CDT for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Apr 11, 2005, 12:12 PM CDT (17:12 UTC)
Expired
Apr 11, 2005, 2:15 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 95 counties

Ashley County, AR, Bradley County, AR, Chicot County, AR, Columbia County, AR, Union County, AR, Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Bienville Parish, LA, Calcasieu Parish, LA, Caldwell Parish, LA, Cameron Parish, LA, Catahoula Parish, LA, Claiborne 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, Lincoln Parish, LA, Livingston Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Tangipahoa Parish, LA, Tensas Parish, LA, Terrebonne Parish, LA, Union Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, Webster Parish, LA, West Baton Rouge Parish, LA, West Carroll Parish, LA, West Feliciana Parish, LA, Winn Parish, LA, Adams County, MS, Amite County, MS, Attala County, MS, Carroll County, MS, Claiborne County, MS, Copiah County, MS, Franklin County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Jefferson County, MS, Lawrence County, MS, Leake County, MS, Leflore County, MS, Lincoln County, MS, Madison County, MS, Montgomery County, MS, Pike County, MS, Rankin County, MS, Scott County, MS, Sharkey County, MS, Simpson County, MS, Sunflower County, MS, Walthall County, MS, Warren County, MS, Washington County, MS, Wilkinson County, MS, Yazoo County, MS, Chambers County, TX, Galveston County, TX, Hardin County, TX, Jasper County, TX, Jefferson County, TX, Newton County, TX, Orange County, TX, Sabine County, TX

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 5.2 hours before the alert went out and 153 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 2005-04-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1084 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 2005-04-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 285 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
1084 J/kg
Mixed-layer CIN
-143 J/kg
Mixed-layer LCL
737 m above ground
0-6 km bulk shear
50 kt
0-1 km storm-relative helicity
285 m²/s²
0-3 km storm-relative helicity
342 m²/s²
Significant tornado parameter
0.8
Supercell composite
12.2

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 10, 8:53 PM CDTMesoscale DiscussionSPCBenton, Crawford, Sebastian, Washington2 hr
Apr 10, 9:15 PM CDTSevere Thunderstorm WatchSPCBenton, Carroll, Clark, Crawford, Franklin, Howard and 10 more7 hr
Apr 11, 1:23 AM CDTMesoscale DiscussionSPCBenton, Carroll, Clark, Crawford, Franklin, Howard and 11 more67 min
Apr 11, 3:12 AM CDTMesoscale DiscussionSPCColumbia, Lafayette, Miller, Union63 min
Apr 11, 3:23 AM CDTMesoscale DiscussionSPCBenton, Carroll, Clark, Crawford, Franklin, Howard and 11 more67 min
Apr 11, 3:45 AM CDTSevere Thunderstorm WatchSPCAshley, Bradley, Columbia, Lafayette, Miller, Union7 hr
Apr 11, 6:17 AM CDTMesoscale DiscussionSPCArkansas, Clay, Cleburne, Conway, Craighead, Crittenden and 27 more118 min
Apr 11, 6:53 AM CDTMesoscale DiscussionSPCAshley, Columbia, Lafayette, Miller, Union67 min
Apr 11, 9:41 AM CDTMesoscale DiscussionSPCAshley, Bradley, Chicot, Columbia, Union2 hr
Apr 11, 10:15 AM CDTTornado WatchSPCAshley, Chicot, Desha, Drew9 hr
Apr 11, 2:01 PM CDTMesoscale DiscussionSPCBenton, Carroll, Madison, Washington89 min
Apr 11, 3:56 AM CDTMesoscale DiscussionSPCFranklin, Madison, Tensas64 min
Apr 11, 1:41 PM CDTMesoscale DiscussionSPCAscension, Assumption, East Baton Rouge, East Feliciana, Iberville, Lafourche and 14 more2 hr
Apr 11, 2:05 PM CDTTornado WatchSPCAscension, Assumption, East Baton Rouge, East Feliciana, Iberia, Iberville and 14 more7 hr
Apr 11, 6:35 PM CDTTornado WatchSPCJefferson, Lafourche, Orleans, Saint Bernard, Saint Charles, Saint Tammany and 1 more4 hr
Apr 11, 6:52 PM CDTMesoscale DiscussionSPCAscension, Assumption, East Baton Rouge, East Feliciana, Iberville, Livingston and 9 more83 min
Apr 11, 1:17 PM CDTMesoscale DiscussionSPCAlcorn, Benton, Coahoma, Itawamba, Lafayette, Lee and 10 more58 min
Apr 11, 1:35 PM CDTTornado WatchSPCAlcorn, Benton, Calhoun, Chickasaw, Itawamba, Lafayette and 10 more5 hr
Apr 10, 7:39 PM CDTMesoscale DiscussionSPCBandera, Bastrop, Bell, Bexar, Blanco, Bosque and 45 more96 min
Apr 10, 10:45 PM CDTSevere Thunderstorm WatchSPCAnderson, Bastrop, Bell, Bexar, Blanco, Brazos and 39 more6 hr

Nearby

Mesoscale Discussions in Louisiana, 2005Mesoscale Discussions in Mississippi, 2005Mesoscale Discussions in Texas, 2005Every mesoscale discussion 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.