Alert archive / Louisiana / Mesoscale Discussions in 2015

Mesoscale Discussion 304

April 15, 201515 parishes in Louisiana; 9 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 15, 2015, 3:46 PM CDT for 15 parishes in Louisiana; 9 counties in Mississippi. It was in force for 89 min.

The area

The outline as issued.

The facts

Issued: Apr 15, 2015, 3:46 PM CDT (20:46 UTC)
Expired: Apr 15, 2015, 5:15 PM CDT
In force: 89 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 24 counties

Ascension Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Iberville Parish, LA, Livingston Parish, LA, Orleans 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 Tammany Parish, LA, Tangipahoa Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, Hancock County, MS, Harrison County, MS, Jackson County, MS, Lamar 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, 8.8 hours before the alert went out and 29 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: 455 J/kg
Mixed-layer CIN: -60 J/kg
Mixed-layer LCL: 598 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 83 m²/s²
0-3 km storm-relative helicity: 83 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.8

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 15, 6:30 PM CDT	Mesoscale Discussion	SPC	Amite, Claiborne, Clarke, Copiah, Covington, Forrest and 24 more	2 hr

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.