Alert archive / Louisiana / Mesoscale Discussions in 2020

Mesoscale Discussion 159

March 4, 2020Mobile County, Alabama; 19 parishes in Louisiana; 15 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Mar 4, 2020, 5:05 PM CST for Mobile County, Alabama; 19 parishes in Louisiana; 15 counties in Mississippi. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Mar 4, 2020, 5:05 PM CST (23:05 UTC)
Expired: Mar 4, 2020, 7:30 PM CST
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 35 counties

Mobile County, AL, Ascension Parish, LA, Assumption Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Iberville Parish, LA, Livingston Parish, LA, Orleans Parish, LA, Pointe Coupee Parish, LA, Saint Bernard 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, Washington Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Amite County, MS, Forrest County, MS, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Lamar County, MS, Marion County, MS, Pearl River County, MS, Perry County, MS, Pike County, MS, Stone County, MS, Walthall County, MS, Wilkinson County, MS

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 11.1 hours before the alert went out and 77 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: 1479 J/kg
Mixed-layer CIN: -69 J/kg
Mixed-layer LCL: 585 m above ground
0-6 km bulk shear: 56 kt
0-1 km storm-relative helicity: 156 m²/s²
0-3 km storm-relative helicity: 351 m²/s²
Significant tornado parameter: 1.3
Supercell composite: 7.9

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 4, 1:19 AM CST	Mesoscale Discussion	SPC	Baldwin, Choctaw, Clarke, Conecuh, Escambia, Marengo and 5 more	2 hr
Mar 4, 1:53 AM CST	Tornado Watch	SPC	Baldwin, Butler, Choctaw, Clarke, Conecuh, Covington and 6 more	8 hr
Mar 4, 2:39 AM CST	Severe Thunderstorm Watch	SPC	Autauga, Barbour, Bullock, Dallas, Elmore, Greene and 9 more	6 hr
Mar 4, 6:37 AM CST	Mesoscale Discussion	SPC	Barbour, Butler, Coffee, Conecuh, Covington, Crenshaw and 7 more	2 hr
Mar 4, 9:16 AM CST	Tornado Watch	SPC	Coffee, Dale, Geneva, Henry, Houston	6 hr
Mar 4, 4:20 AM CST	Mesoscale Discussion	SPC	Bienville, Bossier, Caddo, Caldwell, De Soto, Grant and 11 more	115 min
Mar 4, 5:02 AM CST	Severe Thunderstorm Watch	SPC	Allen, Avoyelles, Beauregard, Bienville, Caldwell, De Soto and 12 more	7 hr
Mar 4, 10:50 AM CST	Mesoscale Discussion	SPC	Allen, Avoyelles, Beauregard, Bienville, Caldwell, Catahoula and 24 more	115 min
Mar 4, 1:57 PM CST	Mesoscale Discussion	SPC	Ascension, Assumption, East Baton Rouge, Iberia, Iberville, Jefferson and 17 more	2 hr

Nearby

Mesoscale Discussions in Louisiana, 2020 Mesoscale Discussions in Mississippi, 2020 Mesoscale Discussions in Alabama, 2020 Every mesoscale discussion in 2020

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.