Alert archive / Louisiana / Mesoscale Discussions in 2003

Mesoscale Discussion 2557

November 26, 200324 parishes in Louisiana; Amite County, Wilkinson County, Mississippi

The Storm Prediction Center issued this mesoscale discussion at Nov 26, 2003, 11:41 PM CST for 24 parishes in Louisiana; Amite County, Wilkinson County, Mississippi. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued: Nov 26, 2003, 11:41 PM CST (05:41 UTC)
Expired: Nov 27, 2003, 1:15 AM CST
In force: 94 min
Issued by: the Storm Prediction Center

All 26 counties

Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Avoyelles Parish, LA, Cameron Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Livingston Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Vermilion Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Amite County, MS, Wilkinson County, MS

The watches that followed

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

Tornado Watch 976Nov 27, 3:00 AM CST

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 00:00Z, 5.7 hours before the alert went out and 105 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: 549 J/kg
Mixed-layer CIN: -30 J/kg
Mixed-layer LCL: 540 m above ground
0-6 km bulk shear: 52 kt
0-1 km storm-relative helicity: 249 m²/s²
0-3 km storm-relative helicity: 305 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 7.0

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 26, 6:55 PM CST	Severe Thunderstorm Watch	SPC	Beauregard, Bossier, Caddo, Calcasieu, Cameron, De Soto and 4 more	6 hr
Nov 26, 9:18 PM CST	Mesoscale Discussion	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 48 more	87 min
Nov 26, 9:55 PM CST	Tornado Watch	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Calcasieu and 19 more	5 hr
Nov 27, 1:36 AM CST	Mesoscale Discussion	SPC	Bienville, Caldwell, Catahoula, Claiborne, Concordia, East Carroll and 13 more	2 hr
Nov 27, 2:31 AM CST	Mesoscale Discussion	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Calcasieu and 19 more	59 min
Nov 27, 3:00 AM CST	Tornado Watch	SPC	Acadia, Ascension, Assumption, Cameron, East Baton Rouge, East Feliciana and 16 more	5 hr
Nov 27, 5:03 AM CST	Mesoscale Discussion	SPC	Acadia, Ascension, Assumption, Cameron, East Baton Rouge, East Feliciana and 16 more	117 min
Nov 27, 5:25 AM CST	Tornado Watch	SPC	Ascension, Assumption, East Baton Rouge, Jefferson, Lafourche, Livingston and 11 more	6 hr
Nov 27, 7:48 AM CST	Mesoscale Discussion	SPC	Ascension, Assumption, East Baton Rouge, Jefferson, Lafourche, Livingston and 10 more	117 min
Nov 27, 7:49 AM CST	Mesoscale Discussion	SPC	Acadia, Calcasieu, Cameron, Iberia, Jefferson Davis, Lafayette and 2 more	2 hr
Nov 27, 9:53 AM CST	Mesoscale Discussion	SPC	Ascension, Assumption, East Baton Rouge, Jefferson, Lafourche, Livingston and 10 more	2 hr

Nearby

Mesoscale Discussions in Louisiana, 2003 Mesoscale Discussions in Mississippi, 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.