Alert archive / Louisiana / Mesoscale Discussions in 2011

Mesoscale Discussion 189

March 5, 2011Mobile County, Alabama; 29 parishes in Louisiana; 8 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Mar 5, 2011, 8:40 AM CST for Mobile County, Alabama; 29 parishes in Louisiana; 8 counties in Mississippi. It was in force for 65 min.

The area

The outline as issued.

The facts

Issued: Mar 5, 2011, 8:40 AM CST (14:40 UTC)
Expired: Mar 5, 2011, 9:45 AM CST
In force: 65 min
Issued by: the Storm Prediction Center

All 38 counties

Mobile County, AL, Acadia Parish, LA, 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, Plaquemines Parish, LA, Pointe Coupee 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 Landry 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, Forrest County, MS, George County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Pearl River County, MS, Perry County, MS, Stone County, MS

The watches that followed

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

Tornado Watch 39Mar 5, 8:55 AM CST

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 2.7 hours before the alert went out and 35 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: 960 J/kg
Mixed-layer CIN: -5 J/kg
Mixed-layer LCL: 451 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 194 m²/s²
0-3 km storm-relative helicity: 264 m²/s²
Significant tornado parameter: 1.0
Supercell composite: 5.8

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
Mar 5, 8:54 AM CST	Tornado Watch	SPC	Baldwin, Choctaw, Clarke, Mobile, Washington	7 hr
Mar 5, 1:31 PM CST	Mesoscale Discussion	SPC	Baldwin, Butler, Coffee, Conecuh, Covington, Crenshaw and 5 more	89 min
Mar 5, 3:13 PM CST	Tornado Watch	SPC	Baldwin, Choctaw, Clarke, Coffee, Conecuh, Covington and 8 more	7 hr
Mar 4, 9:33 PM CST	Mesoscale Discussion	SPC	Saint Tammany, Tangipahoa, Washington	57 min
Mar 5, 11:12 AM CST	Mesoscale Discussion	SPC	Ascension, Assumption, East Baton Rouge, East Feliciana, Jefferson, Lafourche and 12 more	93 min

Nearby

Mesoscale Discussions in Louisiana, 2011 Mesoscale Discussions in Mississippi, 2011 Mesoscale Discussions in Alabama, 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.