Alert archive / Louisiana / Mesoscale Discussions in 2013

Mesoscale Discussion 618

May 10, 201316 parishes in Louisiana; 8 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at May 10, 2013, 2:09 AM CDT for 16 parishes in Louisiana; 8 counties in Mississippi. It was in force for 66 min.

The area

The outline as issued.

The facts

Issued: May 10, 2013, 2:09 AM CDT (07:09 UTC)
Expired: May 10, 2013, 3:15 AM CDT
In force: 66 min
Issued by: the Storm Prediction Center
Chance of a watch: 60%

All 24 counties

Ascension Parish, LA, Assumption Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Iberville Parish, LA, Livingston 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 Tammany Parish, LA, Tangipahoa Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Amite County, MS, Franklin County, MS, Jefferson County, MS, Lawrence County, MS, Lincoln County, MS, Pike County, MS, Walthall County, MS, Wilkinson County, MS

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 154May 10, 2:25 AM CDT

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 00:00Z, 7.2 hours before the alert went out and 126 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: 499 J/kg
Mixed-layer CIN: -99 J/kg
Mixed-layer LCL: 941 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 44 m²/s²
0-3 km storm-relative helicity: 88 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.9

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
May 9, 9:41 PM CDT	Severe Thunderstorm Watch	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 14 more	8 hr
May 10, 2:25 AM CDT	Severe Thunderstorm Watch	SPC	Ascension, Assumption, East Baton Rouge, East Feliciana, Iberia, Iberville and 19 more	8 hr
May 10, 4:32 AM CDT	Mesoscale Discussion	SPC	Ascension, Assumption, Jefferson, Lafourche, Livingston, Saint Charles and 7 more	88 min
May 10, 7:04 AM CDT	Mesoscale Discussion	SPC	Jefferson, Lafourche, Orleans, Plaquemines, Saint Bernard	86 min
May 10, 5:33 PM CDT	Mesoscale Discussion	SPC	Alcorn, Attala, Benton, Bolivar, Calhoun, Carroll and 30 more	117 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.