Alert archive / Louisiana / Mesoscale Discussions in 2015

Mesoscale Discussion 373

April 19, 201517 parishes in Louisiana; 6 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 19, 2015, 2:56 AM CDT for 17 parishes in Louisiana; 6 counties in Mississippi. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued: Apr 19, 2015, 2:56 AM CDT (07:56 UTC)
Expired: Apr 19, 2015, 4:30 AM CDT
In force: 94 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 23 counties

Allen Parish, LA, Avoyelles Parish, LA, Bienville Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Madison Parish, LA, Ouachita Parish, LA, Rapides Parish, LA, Richland Parish, LA, Tensas Parish, LA, Winn Parish, LA, Adams County, MS, Claiborne County, MS, Franklin County, MS, Jefferson County, MS, Warren County, MS, Wilkinson County, MS

The radar

The Ft Polk radar (KPOE), 96 km from the middle of the area, began a volume at 07:57 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

Shreveport, LA (KBAD), launched 00:00Z, 7.9 hours before the alert went out and 162 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: 288 J/kg
Mixed-layer CIN: -49 J/kg
Mixed-layer LCL: 861 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 16 m²/s²
0-3 km storm-relative helicity: 27 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.3

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 19, 2:06 AM CDT	Mesoscale Discussion	SPC	Ascension, Assumption, East Baton Rouge, East Feliciana, Livingston, Orleans and 7 more	84 min
Apr 19, 1:52 PM CDT	Mesoscale Discussion	SPC	Allen, Beauregard, Bienville, Bossier, Caddo, Calcasieu and 16 more	53 min
Apr 19, 2:31 PM CDT	Severe Thunderstorm Watch	SPC	Allen, Beauregard, Bienville, Bossier, Caddo, Calcasieu and 16 more	7 hr
Apr 19, 4:45 PM CDT	Mesoscale Discussion	SPC	Allen, Beauregard, Bienville, Bossier, Caddo, Calcasieu and 22 more	2 hr
Apr 19, 5:46 PM CDT	Tornado Watch	SPC	Bienville, Bossier, Caddo, Caldwell, Catahoula, Claiborne and 20 more	6 hr
Apr 19, 6:56 PM CDT	Mesoscale Discussion	SPC	Cameron	64 min
Apr 19, 1:14 PM CDT	Mesoscale Discussion	SPC	Itawamba, Monroe, Tishomingo	2 hr

Nearby

Mesoscale Discussions in Louisiana, 2015 Mesoscale Discussions in Mississippi, 2015 Every mesoscale discussion in 2015

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.