Alert archive / Louisiana / Mesoscale Discussions in 2011
Mesoscale Discussion 312
The Storm Prediction Center issued this mesoscale discussion at Mar 29, 2011, 8:56 PM CDT for 21 parishes in Louisiana; 14 counties in Mississippi. It was in force for 64 min.
The area
The outline as issued.
The facts
- Issued
- Mar 29, 2011, 8:56 PM CDT (01:56 UTC)
- Expired
- Mar 29, 2011, 10:00 PM CDT
- In force
- 64 min
- Issued by
- the Storm Prediction Center
All 35 counties
Ascension Parish, LA, Assumption Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Iberville Parish, LA, Jefferson Parish, LA, Lafourche Parish, LA, Livingston Parish, LA, Orleans Parish, LA, Plaquemines 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, Terrebonne Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Amite County, MS, Forrest County, MS, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Lamar County, MS, Marion County, MS, Pearl River County, MS, Perry County, MS, Pike County, MS, Stone County, MS, Walthall County, MS
The watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Jackson, MS (KJAN), launched 00:00Z, 1.9 hours before the alert went out and 217 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.
- Mixed-layer CAPE
- 780 J/kg
- Mixed-layer CIN
- -42 J/kg
- Mixed-layer LCL
- 504 m above ground
- 0-6 km bulk shear
- 47 kt
- 0-1 km storm-relative helicity
- 153 m²/s²
- 0-3 km storm-relative helicity
- 257 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 6.8
The text
As transmitted, in the capitals the NWS used until 2016.
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</html>SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 29, 7:40 PM CDT | Mesoscale Discussion | SPC | Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 15 more | 95 min |
| Mar 29, 8:34 PM CDT | Severe Thunderstorm Watch | SPC | Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 10 more | 7 hr |
| Mar 29, 9:42 PM CDT | Tornado Watch | SPC | Ascension, Assumption, East Baton Rouge, East Feliciana, Iberville, Jefferson and 16 more | 7 hr |
| Mar 29, 10:15 PM CDT | Mesoscale Discussion | SPC | Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 7 more | 90 min |
| Mar 29, 11:39 PM CDT | Mesoscale Discussion | SPC | Caldwell, Catahoula, Franklin, Grant, LaSalle, Madison and 1 more | 2 hr |
| Mar 29, 8:13 PM CDT | Mesoscale Discussion | SPC | Alcorn, Benton, DeSoto, Lafayette, Lee, Marshall and 7 more | 2 hr |
Nearby
Mesoscale Discussions in Louisiana, 2011Mesoscale Discussions in Mississippi, 2011Every 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.