Alert archive / Louisiana / Mesoscale Discussions in 2013

Mesoscale Discussion 554

April 24, 201322 parishes in Louisiana; 10 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 24, 2013, 9:00 AM CDT for 22 parishes in Louisiana; 10 counties in Mississippi. It was in force for 90 min.

The area

The outline as issued.

The facts

Issued: Apr 24, 2013, 9:00 AM CDT (14:00 UTC)
Expired: Apr 24, 2013, 10:30 AM CDT
In force: 90 min
Issued by: the Storm Prediction Center

All 32 counties

Ascension Parish, LA, Assumption Parish, LA, East Baton Rouge Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Parish, LA, Lafourche Parish, LA, Livingston Parish, LA, Orleans Parish, LA, Plaquemines 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 Martin Parish, LA, Saint Tammany Parish, LA, St. Mary Parish, LA, Tangipahoa Parish, LA, Terrebonne Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, Forrest County, MS, Hancock County, MS, Harrison County, MS, Lamar County, MS, Lawrence County, MS, Marion County, MS, Pearl River County, MS, Pike County, MS, Stone County, MS, Walthall County, MS

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 2.0 hours before the alert went out and 58 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: 789 J/kg
Mixed-layer CIN: -13 J/kg
Mixed-layer LCL: 481 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 176 m²/s²
0-3 km storm-relative helicity: 265 m²/s²
Significant tornado parameter: 0.6
Supercell composite: 3.7

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 24, 4:51 AM CDT	Mesoscale Discussion	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 3 more	54 min
Apr 24, 6:38 AM CDT	Tornado Watch	SPC	Acadia, Ascension, Assumption, Avoyelles, East Baton Rouge, East Feliciana and 25 more	8 hr
Apr 24, 11:48 AM CDT	Mesoscale Discussion	SPC	Jefferson, Lafourche, Orleans, Plaquemines, Saint Bernard, Saint Charles and 1 more	57 min

Nearby

Mesoscale Discussions in Louisiana, 2013 Mesoscale Discussions in Mississippi, 2013 Every mesoscale discussion in 2013

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.