Alert archive / Louisiana / Mesoscale Discussions in 2016

Mesoscale Discussion 1838

November 29, 201616 parishes in Louisiana; 4 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Nov 29, 2016, 9:51 AM CST for 16 parishes in Louisiana; 4 counties in Texas. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued: Nov 29, 2016, 9:51 AM CST (15:51 UTC)
Expired: Nov 29, 2016, 11:15 AM CST
In force: 84 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Bienville Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, De Soto Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Tensas Parish, LA, Winn Parish, LA, Angelina County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX

The radar

The Ft Polk radar (KPOE), 81 km from the middle of the area, began a volume at 15:50 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 504Nov 29, 1:45 PM CST

The nearest sounding before it

Shreveport, LA (KBAD), launched 12:00Z, 3.9 hours before the alert went out and 91 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2984 m above ground
0-6 km bulk shear: 95 kt
0-1 km storm-relative helicity: 190 m²/s²
0-3 km storm-relative helicity: 198 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

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, 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
Nov 29, 5:37 PM CST	Mesoscale Discussion	SPC	Acadia, Allen, Ascension, Avoyelles, Beauregard, Calcasieu and 12 more	2 hr

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.