Alert archive / Louisiana / Mesoscale Discussions in 2012

Mesoscale Discussion 2206

December 25, 201230 parishes in Louisiana; 15 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Dec 25, 2012, 7:00 AM CST for 30 parishes in Louisiana; 15 counties in Texas. It was in force for 60 min.

The area

The outline as issued.

The facts

Issued: Dec 25, 2012, 7:00 AM CST (13:00 UTC)
Expired: Dec 25, 2012, 8:00 AM CST
In force: 60 min
Issued by: the Storm Prediction Center
Chance of a watch: 95%

All 45 counties

Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Assumption 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, 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 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, Terrebonne Parish, LA, Vermilion Parish, LA, West Baton Rouge Parish, LA, Brazoria County, TX, Chambers County, TX, Galveston County, TX, Hardin County, TX, Harris County, TX, Jasper County, TX, Jefferson County, TX, Liberty County, TX, Montgomery County, TX, Newton County, TX, Orange County, TX, Polk County, TX, San Jacinto County, TX, Tyler County, TX, Walker County, TX

The radar

The Lake Charles radar (KLCH), 36 km from the middle of the area, began a volume at 13:00 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.

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 1.0 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: 1505 J/kg
Mixed-layer CIN: -9 J/kg
Mixed-layer LCL: 500 m above ground
0-6 km bulk shear: 54 kt
0-1 km storm-relative helicity: 265 m²/s²
0-3 km storm-relative helicity: 353 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 10.9

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 25, 1:01 AM CST	Mesoscale Discussion	SPC	Allen, Beauregard, Sabine, Vernon	59 min
Dec 25, 1:37 AM CST	Severe Thunderstorm Watch	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, De Soto and 9 more	7 hr
Dec 25, 5:56 AM CST	Mesoscale Discussion	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, De Soto and 10 more	94 min
Dec 25, 7:28 AM CST	Tornado Watch	SPC	Acadia, Ascension, Assumption, East Baton Rouge, East Feliciana, Iberia and 19 more	6 hr
Dec 25, 8:46 AM CST	Mesoscale Discussion	SPC	Allen, Avoyelles, Beauregard, Bienville, Calcasieu, Caldwell and 21 more	59 min
Dec 25, 9:02 AM CST	Severe Thunderstorm Watch	SPC	Bienville, Bossier, Caddo, Caldwell, Catahoula, Claiborne and 20 more	7 hr
Dec 25, 9:17 AM CST	Tornado Watch	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 10 more	8 hr
Dec 25, 12:19 PM CST	Mesoscale Discussion	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 35 more	71 min
Dec 25, 12:23 PM CST	Mesoscale Discussion	SPC	Bienville, Caldwell, Catahoula, Concordia, East Carroll, Franklin and 13 more	67 min
Dec 25, 12:58 PM CST	Tornado Watch PDS	SPC	Ascension, Assumption, Catahoula, Concordia, East Baton Rouge, East Feliciana and 20 more	9 hr
Dec 25, 3:22 PM CST	Mesoscale Discussion	SPC	Caldwell, East Carroll, Morehouse, Richland, West Carroll	53 min
Dec 25, 3:44 PM CST	Mesoscale Discussion	SPC	Ascension, Assumption, East Baton Rouge, East Feliciana, Iberia, Iberville and 19 more	91 min
Dec 25, 9:31 AM CST	Mesoscale Discussion	SPC	Archer, Baylor, Clay, Cooke, Denton, Hood and 10 more	5 hr
Dec 25, 11:02 AM CST	Mesoscale Discussion	SPC	Wichita, Wilbarger	4 hr
Dec 25, 1:00 PM CST	Mesoscale Discussion	SPC	Bowie, Camp, Cass, Collin, Dallas, Delta and 16 more	5 hr
Dec 25, 2:50 PM CST	Mesoscale Discussion	SPC	Clay, Wichita, Wilbarger	4 hr

Nearby

Mesoscale Discussions in Louisiana, 2012 Mesoscale Discussions in Texas, 2012 Every mesoscale discussion in 2012

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.