Alert archive / Louisiana / Mesoscale Discussions in 2008

Mesoscale Discussion 2249

September 11, 200821 parishes in Louisiana; Hancock County, Harrison County, Jackson County, Mississippi

The Storm Prediction Center issued this mesoscale discussion at Sep 11, 2008, 11:37 PM CDT for 21 parishes in Louisiana; Hancock County, Harrison County, Jackson County, Mississippi. It was in force for 98 min.

The area

The outline as issued.

The facts

Issued: Sep 11, 2008, 11:37 PM CDT (04:37 UTC)
Expired: Sep 12, 2008, 1:15 AM CDT
In force: 98 min
Issued by: the Storm Prediction Center

All 24 counties

Ascension Parish, LA, Assumption Parish, LA, East Baton Rouge Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Parish, LA, Lafayette Parish, LA, Lafourche Parish, LA, Livingston Parish, LA, Orleans Parish, LA, Saint Bernard Parish, LA, Saint Charles 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, West Baton Rouge Parish, LA, Hancock County, MS, Harrison County, MS, Jackson County, MS

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 00:00Z, 4.6 hours before the alert went out and 120 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: 1024 J/kg
Mixed-layer CIN: -4 J/kg
Mixed-layer LCL: 923 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 209 m²/s²
0-3 km storm-relative helicity: 201 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 3.3

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
Sep 12, 3:52 AM CDT	Tornado Watch	SPC	Acadia, Ascension, Assumption, Avoyelles, East Baton Rouge, East Feliciana and 26 more	9 hr
Sep 12, 11:48 AM CDT	Mesoscale Discussion	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 39 more	87 min
Sep 12, 12:46 PM CDT	Tornado Watch	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 32 more	7 hr
Sep 12, 5:55 PM CDT	Mesoscale Discussion	SPC	Acadia, Allen, Assumption, Avoyelles, Beauregard, Calcasieu and 22 more	2 hr

Nearby

Mesoscale Discussions in Louisiana, 2008 Mesoscale Discussions in Mississippi, 2008 Every mesoscale discussion in 2008

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.