Alert archive / Louisiana / Mesoscale Discussions in 2018

Mesoscale Discussion 1630

November 7, 201824 parishes in Louisiana; 10 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Nov 7, 2018, 12:54 PM CST for 24 parishes in Louisiana; 10 counties in Mississippi. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Nov 7, 2018, 12:54 PM CST (18:54 UTC)
Expired: Nov 7, 2018, 3:00 PM CST
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 5%

All 34 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, 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 Martin Parish, LA, Saint Tammany Parish, LA, St. Mary Parish, LA, Tangipahoa Parish, LA, Terrebonne Parish, LA, Vermilion Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, Forrest County, MS, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Lamar County, MS, Pearl River County, MS, Perry County, MS, Stone County, MS

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 6.9 hours before the alert went out and 111 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: 1631 J/kg
Mixed-layer CIN: -6 J/kg
Mixed-layer LCL: 457 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 97 m²/s²
0-3 km storm-relative helicity: 114 m²/s²
Significant tornado parameter: 0.6
Supercell composite: 3.8

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 7, 10:34 AM CST	Mesoscale Discussion	SPC	Clarke, Wayne	56 min

Nearby

Mesoscale Discussions in Louisiana, 2018 Mesoscale Discussions in Mississippi, 2018 Every mesoscale discussion in 2018

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.