Alert archive / Louisiana / Mesoscale Discussions in 2018

Mesoscale Discussion 117

March 11, 201819 parishes in Louisiana

The Storm Prediction Center issued this mesoscale discussion at Mar 11, 2018, 9:46 AM CDT for 19 parishes in Louisiana. It was in force for 119 min.

The area

The outline as issued.

The facts

Issued: Mar 11, 2018, 9:46 AM CDT (14:46 UTC)
Expired: Mar 11, 2018, 11:45 AM CDT
In force: 119 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

Counties Ascension Parish, LA, Assumption Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Iberville Parish, LA, Jefferson Parish, LA, Lafourche Parish, LA, Livingston Parish, LA, Orleans Parish, LA, Pointe Coupee Parish, LA, Saint Charles Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Martin Parish, LA, Saint Tammany Parish, LA, Tangipahoa Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 2.8 hours before the alert went out and 102 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: 204 J/kg
Mixed-layer CIN: -63 J/kg
Mixed-layer LCL: 829 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 134 m²/s²
0-3 km storm-relative helicity: 172 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.5

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
Mar 10, 8:33 PM CST	Severe Thunderstorm Watch	SPC	East Carroll, Morehouse, West Carroll	7 hr
Mar 10, 10:08 PM CST	Mesoscale Discussion	SPC	Bossier, Caddo, Webster	2 hr

Nearby

Mesoscale Discussions in Louisiana, 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.