Alert archive / Louisiana / Mesoscale Discussions in 2003

Mesoscale Discussion 104

February 21, 200322 parishes in Louisiana; 15 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Feb 21, 2003, 4:35 AM CST for 22 parishes in Louisiana; 15 counties in Mississippi. It was in force for 115 min.

The area

The outline as issued.

The facts

Issued: Feb 21, 2003, 4:35 AM CST (10:35 UTC)
Expired: Feb 21, 2003, 6:30 AM CST
In force: 115 min
Issued by: the Storm Prediction Center

All 37 counties

Ascension Parish, LA, Assumption Parish, LA, Avoyelles Parish, LA, Concordia Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Iberville Parish, LA, Lafayette Parish, LA, Livingston Parish, LA, Orleans Parish, LA, Pointe Coupee Parish, LA, Saint Charles Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, Saint Tammany Parish, LA, Tangipahoa Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Adams County, MS, Amite County, MS, Forrest County, MS, Franklin County, MS, Hancock County, MS, Jefferson County, MS, Jefferson Davis County, MS, Lamar County, MS, Lawrence County, MS, Lincoln County, MS, Marion County, MS, Pearl River County, MS, Pike County, MS, Walthall County, MS, Wilkinson County, MS

The nearest sounding before it

Jackson, MS (KJAN), launched 00:00Z, 10.6 hours before the alert went out and 176 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: 4 J/kg
Mixed-layer CIN: -4 J/kg
Mixed-layer LCL: 618 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 65 m²/s²
0-3 km storm-relative helicity: 198 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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
Feb 21, 1:43 AM CST	Mesoscale Discussion	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 6 more	2 hr
Feb 21, 9:02 AM CST	Mesoscale Discussion	SPC	Beauregard, Calcasieu, Cameron, Sabine, Vernon	58 min
Feb 21, 9:40 AM CST	Tornado Watch	SPC	Acadia, Allen, Beauregard, Calcasieu, Caldwell, Cameron and 11 more	6 hr
Feb 21, 11:47 AM CST	Mesoscale Discussion	SPC	Acadia, Allen, Beauregard, Calcasieu, Cameron, Evangeline and 4 more	118 min
Feb 21, 3:32 PM CST	Mesoscale Discussion	SPC	Allen, Beauregard, Calcasieu, Evangeline, Jefferson Davis, Vernon	118 min
Feb 21, 3:40 PM CST	Tornado Watch	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 32 more	6 hr
Feb 21, 5:20 PM CST	Mesoscale Discussion	SPC	Claiborne, East Carroll, Franklin, Jackson, Lincoln, Madison and 5 more	4 hr
Feb 21, 5:50 PM CST	Mesoscale Discussion	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 32 more	115 min

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.