Alert archive / Louisiana / Mesoscale Discussions in 2015

Mesoscale Discussion 289

April 13, 201528 parishes in Louisiana; Hancock County, Harrison County, Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 13, 2015, 7:59 AM CDT for 28 parishes in Louisiana; Hancock County, Harrison County, Mississippi. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Apr 13, 2015, 7:59 AM CDT (12:59 UTC)
Expired: Apr 13, 2015, 10:00 AM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 30 counties

Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Beauregard Parish, LA, East Baton Rouge Parish, LA, Evangeline Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Davis 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 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, Terrebonne Parish, LA, West Baton Rouge Parish, LA, Hancock County, MS, Harrison County, MS

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 1.0 hours before the alert went out and 129 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: 1296 J/kg
Mixed-layer CIN: -24 J/kg
Mixed-layer LCL: 590 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 188 m²/s²
0-3 km storm-relative helicity: 262 m²/s²
Significant tornado parameter: 0.8
Supercell composite: 5.2

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 13, 10:42 AM CDT	Mesoscale Discussion	SPC	Plaquemines, Saint Bernard	63 min

Nearby

Mesoscale Discussions in Louisiana, 2015 Mesoscale Discussions in Mississippi, 2015 Every mesoscale discussion in 2015

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.