Alert archive / Louisiana / Mesoscale Discussions in 2003

Mesoscale Discussion 2514

November 17, 200317 parishes in Louisiana; Sabine County, San Augustine County, Texas

The Storm Prediction Center issued this mesoscale discussion at Nov 17, 2003, 11:44 PM CST for 17 parishes in Louisiana; Sabine County, San Augustine County, Texas. It was in force for 91 min.

The area

The outline as issued.

The facts

Issued: Nov 17, 2003, 11:44 PM CST (05:44 UTC)
Expired: Nov 18, 2003, 1:15 AM CST
In force: 91 min
Issued by: the Storm Prediction Center

Counties Bienville Parish, LA, Bossier Parish, LA, Caldwell Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Rapides Parish, LA, Red River Parish, LA, Sabine Parish, LA, Union Parish, LA, Webster Parish, LA, Winn Parish, LA, Sabine County, TX, San Augustine County, TX

The watches that followed

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

Tornado Watch 957Nov 18, 2:25 AM CST

The nearest sounding before it

Shreveport, LA (KSHV), launched 00:00Z, 5.7 hours before the alert went out and 83 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: 512 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 515 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 231 m²/s²
0-3 km storm-relative helicity: 284 m²/s²
Significant tornado parameter: 0.6
Supercell composite: 3.6

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
Nov 17, 7:48 PM CST	Mesoscale Discussion	SPC	Bossier, Caddo, Claiborne, Webster	87 min
Nov 17, 8:10 PM CST	Mesoscale Discussion	SPC	Beauregard, Calcasieu, Natchitoches, Sabine, Vernon	95 min
Nov 17, 9:25 PM CST	Tornado Watch	SPC	Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 12 more	7 hr
Nov 17, 10:53 PM CST	Mesoscale Discussion	SPC	Beauregard, Calcasieu	97 min
Nov 17, 11:50 PM CST	Tornado Watch	SPC	Acadia, Allen, Beauregard, Calcasieu, Cameron, Evangeline and 2 more	5 hr
Nov 18, 2:08 AM CST	Mesoscale Discussion	SPC	Ascension, Assumption, Avoyelles, Catahoula, Concordia, East Baton Rouge and 25 more	97 min
Nov 18, 2:25 AM CST	Tornado Watch	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 32 more	6 hr
Nov 18, 4:48 AM CST	Mesoscale Discussion	SPC	Ascension, Assumption, Concordia, East Baton Rouge, East Feliciana, Iberville and 17 more	117 min
Nov 18, 6:08 AM CST	Mesoscale Discussion	SPC	Ascension, Jefferson, Lafourche, Livingston, Orleans, Plaquemines and 8 more	2 hr
Nov 18, 6:55 AM CST	Tornado Watch	SPC	Ascension, Assumption, East Baton Rouge, Jefferson, Lafourche, Livingston and 11 more	5 hr
Nov 18, 10:30 AM CST	Mesoscale Discussion	SPC	Saint Bernard	90 min
Nov 17, 6:55 PM CST	Severe Thunderstorm Watch	SPC	Austin, Brazoria, Colorado, Fort Bend, Grimes, Harris and 12 more	5 hr

Nearby

Mesoscale Discussions in Louisiana, 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.