Alert archive / Louisiana / Mesoscale Discussions in 2003

Mesoscale Discussion 420

April 6, 20034 states

The Storm Prediction Center issued this mesoscale discussion at Apr 6, 2003, 5:35 PM CDT for 4 states. It was in force for 115 min.

The area

The outline as issued.

The facts

Issued: Apr 6, 2003, 5:35 PM CDT (22:35 UTC)
Expired: Apr 6, 2003, 7:30 PM CDT
In force: 115 min
Issued by: the Storm Prediction Center

All 82 counties

Ashley County, AR, Chicot County, AR, Union County, AR, Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, Claiborne Parish, LA, Concordia Parish, LA, De Soto Parish, LA, East Carroll Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Rapides Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Tensas Parish, LA, Union Parish, LA, Vernon Parish, LA, Webster Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Adams County, MS, Amite County, MS, Attala County, MS, Carroll County, MS, Claiborne County, MS, Copiah County, MS, Covington County, MS, Franklin County, MS, Grenada County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Jefferson County, MS, Jefferson Davis County, MS, Lawrence County, MS, Leake County, MS, Leflore County, MS, Lincoln County, MS, Madison County, MS, Montgomery County, MS, Rankin County, MS, Scott County, MS, Sharkey County, MS, Simpson County, MS, Smith County, MS, Sunflower County, MS, Warren County, MS, Washington County, MS, Wilkinson County, MS, Yazoo County, MS, Angelina County, TX, Gregg County, TX, Hardin County, TX, Harrison County, TX, Jasper County, TX, Liberty County, TX, Marion County, TX, Nacogdoches County, TX, Newton County, TX, Panola County, TX, Polk County, TX, Rusk County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX, Tyler County, TX

The watches that followed

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

Tornado Watch 108Apr 6, 6:50 PM CDT

The nearest sounding before it

Shreveport, LA (KSHV), launched 12:00Z, 10.6 hours before the alert went out and 158 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1292 J/kg
Mixed-layer CIN: -53 J/kg
Mixed-layer LCL: 492 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 259 m²/s²
0-3 km storm-relative helicity: 405 m²/s²
Significant tornado parameter: 2.5
Supercell composite: 20.3

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.

Issued	Product	Office	Counties	Lasted
Apr 6, 7:38 AM CDT	Mesoscale Discussion	SPC	Ashley, Bradley, Calhoun, Chicot, Columbia, Lafayette and 3 more	97 min
Apr 6, 7:50 AM CDT	Severe Thunderstorm Watch	SPC	Ashley, Bradley, Calhoun, Chicot, Columbia, Drew and 6 more	5 hr
Apr 6, 8:56 AM CDT	Mesoscale Discussion	SPC	Baxter, Benton, Boone, Carroll, Cleburne, Conway and 21 more	2 hr
Apr 6, 9:45 AM CDT	Severe Thunderstorm Watch	SPC	Baxter, Benton, Boone, Carroll, Conway, Crawford and 22 more	5 hr
Apr 6, 10:00 AM CDT	Mesoscale Discussion	SPC	Arkansas, Ashley, Chicot, Desha, Drew, Jefferson and 4 more	2 hr
Apr 6, 10:20 AM CDT	Mesoscale Discussion	SPC	Arkansas, Ashley, Bradley, Calhoun, Chicot, Clark and 21 more	55 min
Apr 6, 10:30 AM CDT	Tornado Watch	SPC	Ashley, Bradley, Calhoun, Chicot, Columbia, Drew and 6 more	6 hr
Apr 6, 11:05 AM CDT	Severe Thunderstorm Watch	SPC	Arkansas, Baxter, Cleburne, Cleveland, Craighead, Crittenden and 27 more	5 hr
Apr 6, 12:27 PM CDT	Mesoscale Discussion	SPC	Arkansas, Clark, Cleburne, Cleveland, Conway, Craighead and 46 more	2 hr
Apr 6, 2:18 PM CDT	Mesoscale Discussion	SPC	Boone, Conway, Crawford, Franklin, Garland, Howard and 16 more	57 min
Apr 6, 2:55 PM CDT	Severe Thunderstorm Watch	SPC	Baxter, Boone, Clark, Cleburne, Conway, Crawford and 35 more	5 hr
Apr 6, 3:45 PM CDT	Tornado Watch	SPC	Ashley, Chicot, Union	5 hr
Apr 6, 6:23 PM CDT	Mesoscale Discussion	SPC	Ashley, Chicot, Union	97 min
Apr 6, 12:03 PM CDT	Mesoscale Discussion	SPC	Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 14 more	117 min
Apr 6, 3:26 PM CDT	Mesoscale Discussion	SPC	Bienville, Caldwell, De Soto, Franklin, Grant, Jackson and 11 more	2 hr
Apr 6, 6:50 PM CDT	Tornado Watch	SPC	Avoyelles, Caldwell, Catahoula, Concordia, East Carroll, Evangeline and 11 more	6 hr
Apr 6, 12:40 PM CDT	Mesoscale Discussion	SPC	Attala, Choctaw, Holmes, Kemper, Lauderdale, Leake and 9 more	2 hr
Apr 6, 1:35 PM CDT	Tornado Watch	SPC	Choctaw, Clarke, Jasper, Jones, Kemper, Lauderdale and 7 more	5 hr
Apr 6, 2:56 PM CDT	Mesoscale Discussion	SPC	Kemper, Lauderdale, Leake, Neshoba, Newton, Noxubee and 2 more	2 hr
Apr 5, 6:11 PM CST	Mesoscale Discussion	SPC	Baylor, Briscoe, Cottle, Crosby, Dickens, Floyd and 9 more	64 min
Apr 5, 6:35 PM CST	Mesoscale Discussion	SPC	Archer, Clay, Collin, Cooke, Dallas, Delta and 23 more	115 min
Apr 5, 6:40 PM CST	Tornado Watch	SPC	Briscoe, Childress, Cottle, Crosby, Dickens, Fisher and 16 more	5 hr
Apr 5, 8:04 PM CST	Mesoscale Discussion	SPC	Archer, Baylor, Clay, Collin, Cooke, Dallas and 25 more	116 min
Apr 5, 9:20 PM CST	Mesoscale Discussion	SPC	Archer, Camp, Clay, Collin, Cooke, Dallas and 31 more	55 min
Apr 5, 9:35 PM CST	Tornado Watch	SPC	Archer, Bowie, Camp, Cass, Clay, Collin and 38 more	5 hr
Apr 5, 10:26 PM CST	Mesoscale Discussion	SPC	Baylor, Childress, Cottle, Dickens, Fisher, Foard and 11 more	64 min
Apr 5, 11:43 PM CST	Mesoscale Discussion	SPC	Archer, Camp, Clay, Collin, Cooke, Dallas and 31 more	92 min
Apr 6, 3:13 AM CDT	Mesoscale Discussion	SPC	Archer, Baylor, Camp, Cass, Cherokee, Clay and 39 more	107 min
Apr 6, 3:39 AM CDT	Mesoscale Discussion	SPC	Archer, Baylor, Camp, Cass, Cherokee, Clay and 39 more	66 min
Apr 6, 4:50 AM CDT	Mesoscale Discussion	SPC	Archer, Baylor, Brown, Callahan, Coke, Coleman and 27 more	115 min
Apr 6, 5:35 AM CDT	Severe Thunderstorm Watch	SPC	Wichita	4 hr
Apr 6, 9:12 AM CDT	Mesoscale Discussion	SPC	Anderson, Bosque, Camp, Cass, Cherokee, Collin and 41 more	2 hr
Apr 6, 12:40 PM CDT	Tornado Watch	SPC	Anderson, Brazos, Burleson, Cherokee, Collin, Cooke and 33 more	5 hr
Apr 6, 3:00 PM CDT	Mesoscale Discussion	SPC	Anderson, Brazos, Cherokee, Delta, Freestone, Grimes and 21 more	90 min

Nearby

Mesoscale Discussions in Louisiana, 2003 Mesoscale Discussions in Mississippi, 2003 Mesoscale Discussions in Texas, 2003 Every mesoscale discussion in 2003

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.