Alert archive / Mississippi / Mesoscale Discussions in 2011

Mesoscale Discussion 2388

December 22, 201125 parishes in Louisiana; 37 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Dec 22, 2011, 7:50 AM CST for 25 parishes in Louisiana; 37 counties in Mississippi. It was in force for 55 min.

The area

The outline as issued.

The facts

Issued: Dec 22, 2011, 7:50 AM CST (13:50 UTC)
Expired: Dec 22, 2011, 8:45 AM CST
In force: 55 min
Issued by: the Storm Prediction Center

All 62 counties

Ascension Parish, LA, Assumption Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Parish, LA, Lafayette Parish, LA, Lafourche Parish, LA, Livingston Parish, LA, Orleans 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 Martin Parish, LA, Saint Tammany Parish, LA, St. Mary Parish, LA, Tangipahoa Parish, LA, Terrebonne Parish, LA, Vermilion Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Amite County, MS, Attala County, MS, Choctaw County, MS, Clarke County, MS, Clay County, MS, Copiah County, MS, Covington County, MS, Forrest County, MS, Franklin County, MS, Hinds County, MS, Jasper County, MS, Jefferson Davis County, MS, Jones County, MS, Kemper County, MS, Lamar County, MS, Lauderdale County, MS, Lawrence County, MS, Leake County, MS, Lincoln County, MS, Lowndes County, MS, Madison County, MS, Marion County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS, Oktibbeha County, MS, Pearl River County, MS, Pike County, MS, Rankin County, MS, Scott County, MS, Simpson County, MS, Smith County, MS, Walthall County, MS, Wayne County, MS, Webster County, MS, Wilkinson County, MS, Winston County, MS

The watches that followed

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

Tornado Watch 899Dec 22, 10:00 AM CST

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 1.8 hours before the alert went out and 104 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: 578 J/kg
Mixed-layer CIN: -18 J/kg
Mixed-layer LCL: 476 m above ground
0-6 km bulk shear: 58 kt
0-1 km storm-relative helicity: 244 m²/s²
0-3 km storm-relative helicity: 297 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 3.4

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
Dec 22, 4:11 AM CST	Mesoscale Discussion	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Calcasieu and 32 more	34 min
Dec 22, 4:36 AM CST	Tornado Watch	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Calcasieu and 32 more	7 hr
Dec 22, 9:32 AM CST	Mesoscale Discussion	SPC	Saint Bernard	58 min
Dec 22, 10:00 AM CST	Tornado Watch	SPC	Plaquemines, Saint Bernard	7 hr
Dec 22, 2:51 PM CST	Mesoscale Discussion	SPC	Saint Tammany	54 min
Dec 22, 11:22 AM CST	Mesoscale Discussion	SPC	George, Greene	53 min

Nearby

Mesoscale Discussions in Mississippi, 2011 Mesoscale Discussions in Louisiana, 2011 Every mesoscale discussion in 2011

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.