Alert archive / Louisiana / Mesoscale Discussions in 2019

Mesoscale Discussion 685

May 19, 201923 parishes in Louisiana; 8 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at May 19, 2019, 7:50 AM CDT for 23 parishes in Louisiana; 8 counties in Mississippi. It was in force for 85 min.

The area

The outline as issued.

The facts

Issued: May 19, 2019, 7:50 AM CDT (12:50 UTC)
Expired: May 19, 2019, 9:15 AM CDT
In force: 85 min
Issued by: the Storm Prediction Center

All 31 counties

Ascension Parish, LA, Assumption Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Iberia Parish, LA, Iberville 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, St. Mary Parish, LA, Tangipahoa Parish, LA, Terrebonne Parish, LA, Vermilion Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Amite County, MS, Franklin County, MS, Lawrence County, MS, Lincoln County, MS, Marion County, MS, Pike County, MS, Walthall County, MS, Wilkinson County, MS

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 0.8 hours before the alert went out and 157 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: 2341 J/kg
Mixed-layer CIN: 0 J/kg
Mixed-layer LCL: 562 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 37 m²/s²
0-3 km storm-relative helicity: 52 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.6

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
May 18, 7:08 PM CDT	Tornado Watch	SPC	Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 11 more	7 hr
May 18, 11:53 PM CDT	Mesoscale Discussion	SPC	Bienville, Caldwell, De Soto, Grant, Jackson, Lincoln and 7 more	97 min
May 19, 1:02 AM CDT	Mesoscale Discussion	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Caldwell and 16 more	58 min
May 19, 1:47 AM CDT	Tornado Watch	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 49 more	9 hr
May 19, 3:49 PM CDT	Mesoscale Discussion	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 12 more	86 min
May 18, 9:00 PM CDT	Mesoscale Discussion	SPC	DeSoto, Marshall, Panola, Quitman, Tate, Tunica	60 min

Nearby

Mesoscale Discussions in Louisiana, 2019 Mesoscale Discussions in Mississippi, 2019 Every mesoscale discussion in 2019

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.