Alert archive / Louisiana / Mesoscale Discussions in 2019

Mesoscale Discussion 2103

October 21, 20194 states

The Storm Prediction Center issued this mesoscale discussion at Oct 21, 2019, 11:47 AM CDT for 4 states. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued: Oct 21, 2019, 11:47 AM CDT (16:47 UTC)
Expired: Oct 21, 2019, 1:15 PM CDT
In force: 88 min
Issued by: the Storm Prediction Center
Chance of a watch: 60%

Counties Baldwin County, AL, Mobile County, AL, Washington County, AL, Escambia County, FL, Jefferson Parish, LA, Lafourche Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Saint Bernard Parish, LA, Saint Charles Parish, LA, Saint John the Baptist Parish, LA, Saint Tammany Parish, LA, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Stone County, MS

The radar

The Mobile radar (KMOB), 96 km from the middle of the area, began a volume at 16:49 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 4.8 hours before the alert went out and 75 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: 39 J/kg
Mixed-layer CIN: -221 J/kg
Mixed-layer LCL: 1075 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: 158 m²/s²
0-3 km storm-relative helicity: 205 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.8

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
Oct 21, 1:49 PM CDT	Mesoscale Discussion	SPC	Conecuh, Covington, Escambia	2 hr
Oct 20, 7:01 PM CDT	Tornado Watch	SPC	Bossier, Caddo, Claiborne, De Soto, Webster	7 hr
Oct 21, 1:50 AM CDT	Tornado Watch	SPC	Bossier, Caddo, Claiborne, De Soto, Webster	5 hr
Oct 21, 4:57 AM CDT	Mesoscale Discussion	SPC	Bienville, Caldwell, East Carroll, Franklin, Jackson, Lincoln and 8 more	63 min
Oct 21, 5:30 AM CDT	Severe Thunderstorm Watch	SPC	Bienville, Caldwell, East Carroll, Franklin, Jackson, Lincoln and 10 more	4 hr
Oct 21, 8:59 AM CDT	Mesoscale Discussion	SPC	Allen, Avoyelles, Concordia, Evangeline, Tensas	91 min
Oct 21, 3:06 AM CDT	Tornado Watch	SPC	Benton, Calhoun, Coahoma, DeSoto, Lafayette, Marshall and 9 more	6 hr

Nearby

Mesoscale Discussions in Louisiana, 2019 Mesoscale Discussions in Mississippi, 2019 Mesoscale Discussions in Alabama, 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; radar from the NEXRAD Level II archive.