Alert archive / Louisiana / Mesoscale Discussions in 2017

Mesoscale Discussion 74

January 19, 201715 parishes in Louisiana; 14 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Jan 19, 2017, 6:28 AM CST for 15 parishes in Louisiana; 14 counties in Mississippi. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jan 19, 2017, 6:28 AM CST (12:28 UTC)
Expired: Jan 19, 2017, 8:30 AM CST
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 29 counties

Ascension Parish, LA, Assumption Parish, LA, Concordia Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Iberville Parish, LA, Livingston Parish, LA, Madison Parish, LA, Pointe Coupee Parish, LA, Saint Helena Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Tensas Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Adams County, MS, Amite County, MS, Claiborne County, MS, Copiah County, MS, Franklin County, MS, Hinds County, MS, Jefferson County, MS, Lawrence County, MS, Lincoln County, MS, Pike County, MS, Rankin County, MS, Simpson County, MS, Warren County, MS, Wilkinson County, MS

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 0.5 hours before the alert went out and 164 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: 733 J/kg
Mixed-layer CIN: -2 J/kg
Mixed-layer LCL: 443 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 120 m²/s²
0-3 km storm-relative helicity: 137 m²/s²
Significant tornado parameter: 0.4
Supercell composite: 2.1

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
Jan 18, 6:06 PM CST	Mesoscale Discussion	SPC	Catahoula, Franklin, Grant, LaSalle, Tensas	114 min
Jan 18, 11:56 PM CST	Mesoscale Discussion	SPC	Acadia, Allen, Avoyelles, Catahoula, Concordia, Evangeline and 5 more	2 hr
Jan 19, 3:10 PM CST	Mesoscale Discussion	SPC	Plaquemines, Saint Bernard	2 hr

Nearby

Mesoscale Discussions in Louisiana, 2017 Mesoscale Discussions in Mississippi, 2017 Every mesoscale discussion in 2017

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.