Alert archive / Louisiana / Mesoscale Discussions in 2016

Mesoscale Discussion 1844

November 29, 201618 parishes in Louisiana; Orange County, Texas

The Storm Prediction Center issued this mesoscale discussion at Nov 29, 2016, 5:37 PM CST for 18 parishes in Louisiana; Orange County, Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Nov 29, 2016, 5:37 PM CST (23:37 UTC)
Expired: Nov 29, 2016, 8:00 PM CST
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 40%

Counties Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Pointe Coupee Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, Vernon Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Orange County, TX

The radar

The Lake Charles radar (KLCH), 57 km from the middle of the area, began a volume at 23:36 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 508Nov 29, 8:50 PM CST

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 11.6 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: 1340 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 590 m above ground
0-6 km bulk shear: 57 kt
0-1 km storm-relative helicity: 132 m²/s²
0-3 km storm-relative helicity: 149 m²/s²
Significant tornado parameter: 1.2
Supercell composite: 6.5

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Nov 28, 6:36 PM CST	Mesoscale Discussion	SPC	Saint Helena, Tangipahoa, Washington	2 hr
Nov 28, 8:39 PM CST	Mesoscale Discussion	SPC	East Baton Rouge, East Feliciana, Livingston, Saint Helena, Tangipahoa, Washington and 1 more	96 min
Nov 28, 11:38 PM CST	Mesoscale Discussion	SPC	Livingston, Saint Tammany, Tangipahoa, Washington	3 hr
Nov 29, 9:51 AM CST	Mesoscale Discussion	SPC	Bienville, Caldwell, Catahoula, De Soto, Franklin, Grant and 10 more	84 min
Nov 29, 12:38 PM CST	Mesoscale Discussion	SPC	Avoyelles, Caldwell, Catahoula, Concordia, East Carroll, Franklin and 13 more	2 hr
Nov 29, 1:48 PM CST	Tornado Watch	SPC	Caldwell, Catahoula, Concordia, East Carroll, Franklin, Grant and 12 more	7 hr
Nov 29, 4:20 PM CST	Mesoscale Discussion	SPC	Caldwell, Catahoula, East Carroll, Franklin, LaSalle, Madison and 2 more	55 min

Nearby

Mesoscale Discussions in Louisiana, 2016 Mesoscale Discussions in Texas, 2016 Every mesoscale discussion in 2016

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.