Alert archive / Louisiana / Mesoscale Discussions in 2004

Mesoscale Discussion 495

April 29, 200429 parishes in Louisiana; 29 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 29, 2004, 1:56 PM CDT for 29 parishes in Louisiana; 29 counties in Mississippi. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Apr 29, 2004, 1:56 PM CDT (18:56 UTC)
Expired: Apr 29, 2004, 4:00 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 58 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, Jefferson Parish, LA, Lafayette Parish, LA, Lafourche Parish, LA, Livingston Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Pointe Coupee Parish, LA, Saint Bernard 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, St. Mary Parish, LA, Tangipahoa Parish, LA, Tensas Parish, LA, Terrebonne Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Adams County, MS, Amite County, MS, Claiborne County, MS, Copiah County, MS, Covington County, MS, Forrest County, MS, Franklin County, MS, Hancock County, MS, Harrison County, MS, Hinds County, MS, Jasper County, MS, Jefferson County, MS, Jefferson Davis County, MS, Jones County, MS, Lamar County, MS, Lawrence County, MS, Lincoln County, MS, Madison County, MS, Marion County, MS, Pearl River County, MS, Pike County, MS, Rankin County, MS, Scott County, MS, Simpson County, MS, Smith County, MS, Stone County, MS, Walthall County, MS, Warren 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 126Apr 29, 3:15 PM CDT

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 6.9 hours before the alert went out and 102 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: 11 J/kg
Mixed-layer CIN: -529 J/kg
Mixed-layer LCL: 922 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 220 m²/s²
0-3 km storm-relative helicity: 374 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
Apr 29, 11:22 AM CDT	Mesoscale Discussion	SPC	Caldwell, Catahoula, Franklin, Grant, LaSalle, Madison and 8 more	113 min
Apr 29, 1:10 PM CDT	Tornado Watch	SPC	Bienville, Caldwell, Catahoula, Claiborne, De Soto, East Carroll and 16 more	6 hr
Apr 29, 3:15 PM CDT	Tornado Watch	SPC	Plaquemines, Saint Bernard	6 hr
Apr 29, 5:36 PM CDT	Mesoscale Discussion	SPC	Caldwell, Catahoula, Concordia, East Carroll, Franklin, LaSalle and 4 more	84 min
Apr 29, 6:15 PM CDT	Mesoscale Discussion	SPC	Orleans, Saint Bernard, Saint Tammany	90 min
Apr 29, 2:44 PM CDT	Mesoscale Discussion	SPC	Washington	2 hr
Apr 29, 6:55 PM CDT	Tornado Watch	SPC	Attala, Carroll, Choctaw, Hinds, Holmes, Leake and 5 more	3 hr

Nearby

Mesoscale Discussions in Louisiana, 2004 Mesoscale Discussions in Mississippi, 2004 Every mesoscale discussion in 2004

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.