Alert archive / Louisiana / Mesoscale Discussions in 2007

Mesoscale Discussion 140

February 12, 200722 parishes in Louisiana; Wilkinson County, Mississippi; Jefferson County, Texas

The Storm Prediction Center issued this mesoscale discussion at Feb 12, 2007, 9:38 PM CST for 22 parishes in Louisiana; Wilkinson County, Mississippi; Jefferson County, Texas. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued: Feb 12, 2007, 9:38 PM CST (03:38 UTC)
Expired: Feb 12, 2007, 11:15 PM CST
In force: 97 min
Issued by: the Storm Prediction Center

All 24 counties

Acadia Parish, LA, Allen Parish, LA, Assumption Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, East Baton Rouge Parish, LA, Evangeline Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Wilkinson County, MS, Jefferson County, TX

The radar

The Lake Charles radar (KLCH), 58 km from the middle of the area, began a volume at 03:41 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The watches that followed

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

Tornado Watch 18Feb 12, 10:40 PM CST

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 00:00Z, 3.6 hours before the alert went out and 57 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: 276 J/kg
Mixed-layer CIN: -24 J/kg
Mixed-layer LCL: 585 m above ground
0-6 km bulk shear: 61 kt
0-1 km storm-relative helicity: 258 m²/s²
0-3 km storm-relative helicity: 297 m²/s²
Significant tornado parameter: 0.4
Supercell composite: 2.4

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
Feb 12, 6:27 PM CST	Mesoscale Discussion	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 10 more	2 hr
Feb 12, 10:39 PM CST	Tornado Watch	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Calcasieu and 30 more	7 hr
Feb 13, 2:26 AM CST	Mesoscale Discussion	SPC	Ascension, Assumption, Lafourche, Livingston, Orleans, Saint Charles and 5 more	64 min
Feb 13, 5:26 AM CST	Mesoscale Discussion	SPC	Orleans, Saint Bernard	94 min
Feb 13, 2:05 AM CST	Mesoscale Discussion	SPC	Covington, Forrest, George, Greene, Jefferson Davis, Jones and 9 more	55 min
Feb 13, 2:43 AM CST	Tornado Watch	SPC	Amite, Clarke, Covington, Forrest, George, Greene and 18 more	10 hr
Feb 13, 4:50 AM CST	Mesoscale Discussion	SPC	Kemper, Lauderdale	85 min
Feb 13, 7:24 AM CST	Mesoscale Discussion	SPC	Jackson	96 min
Feb 13, 11:03 AM CST	Mesoscale Discussion	SPC	Alcorn, Benton, Bolivar, Calhoun, Chickasaw, Choctaw and 25 more	87 min
Feb 13, 12:49 PM CST	Severe Thunderstorm Watch	SPC	Alcorn, Attala, Benton, Calhoun, Carroll, Chickasaw and 33 more	6 hr

Nearby

Mesoscale Discussions in Louisiana, 2007 Mesoscale Discussions in Mississippi, 2007 Mesoscale Discussions in Texas, 2007 Every mesoscale discussion in 2007

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; radar from the NEXRAD Level II archive.