Alert archive / Louisiana / Mesoscale Discussions in 2020

Mesoscale Discussion 415

April 19, 2020Mobile County, Alabama; 10 parishes in Louisiana; 8 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 19, 2020, 9:07 PM CDT for Mobile County, Alabama; 10 parishes in Louisiana; 8 counties in Mississippi. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued: Apr 19, 2020, 9:07 PM CDT (02:07 UTC)
Expired: Apr 19, 2020, 10:30 PM CDT
In force: 83 min
Issued by: the Storm Prediction Center

Counties Mobile County, AL, Ascension Parish, LA, Livingston Parish, LA, Orleans Parish, LA, Saint Bernard Parish, LA, Saint Charles Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Tammany Parish, LA, Tangipahoa Parish, LA, Washington Parish, LA, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Pearl River County, MS, Perry County, MS, Stone County, MS

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Tornado Watch 124Apr 19, 9:35 PM CDT

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 00:00Z, 2.1 hours before the alert went out and 36 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: 2097 J/kg
Mixed-layer CIN: -13 J/kg
Mixed-layer LCL: 819 m above ground
0-6 km bulk shear: 65 kt
0-1 km storm-relative helicity: 202 m²/s²
0-3 km storm-relative helicity: 227 m²/s²
Significant tornado parameter: 2.5
Supercell composite: 9.5

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
Apr 19, 8:25 PM CDT	Mesoscale Discussion	SPC	Barbour, Bullock, Crenshaw, Dale, Henry, Macon and 3 more	65 min
Apr 19, 9:39 PM CDT	Tornado Watch	SPC	Baldwin, Butler, Clarke, Conecuh, Covington, Crenshaw and 5 more	5 hr
Apr 19, 9:53 PM CDT	Mesoscale Discussion	SPC	Dale, Geneva, Henry, Houston	67 min
Apr 19, 10:13 PM CDT	Tornado Watch	SPC	Barbour, Coffee, Dale, Geneva, Henry, Houston and 1 more	10 hr
Apr 19, 7:42 PM CDT	Mesoscale Discussion	SPC	Forrest, Greene, Lamar, Perry	33 min

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.