Alert archive / Louisiana / Mesoscale Discussions in 2015

Mesoscale Discussion 443

April 24, 20154 states

The Storm Prediction Center issued this mesoscale discussion at Apr 24, 2015, 9:20 PM CDT for 4 states. It was in force for 55 min.

The area

The outline as issued.

The facts

Issued: Apr 24, 2015, 9:20 PM CDT (02:20 UTC)
Expired: Apr 24, 2015, 10:15 PM CDT
In force: 55 min
Issued by: the Storm Prediction Center

All 30 counties

Ashley County, AR, Chicot County, AR, Columbia County, AR, Lafayette County, AR, Union County, AR, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Caldwell Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, East Carroll Parish, LA, Franklin Parish, LA, Jackson Parish, LA, Lincoln Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Richland Parish, LA, Union Parish, LA, Webster Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Issaquena County, MS, Sharkey County, MS, Warren County, MS, Washington County, MS, Harrison County, TX, Panola County, TX

The watches that followed

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

Tornado Watch 105Apr 24, 9:55 PM CDT

The nearest sounding before it

Shreveport, LA (KBAD), launched 00:00Z, 2.3 hours before the alert went out and 100 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: 310 J/kg
Mixed-layer CIN: -118 J/kg
Mixed-layer LCL: 809 m above ground
0-6 km bulk shear: 73 kt
0-1 km storm-relative helicity: 317 m²/s²
0-3 km storm-relative helicity: 428 m²/s²
Significant tornado parameter: 0.5
Supercell composite: 9.9

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 24, 7:46 PM CDT	Mesoscale Discussion	SPC	Columbia, Lafayette, Miller, Union	89 min
Apr 24, 9:59 PM CDT	Tornado Watch	SPC	Ashley, Bradley, Calhoun, Chicot, Cleveland, Columbia and 5 more	4 hr
Apr 24, 11:45 PM CDT	Mesoscale Discussion	SPC	Caldwell, East Carroll, Franklin, Jackson, Madison, Morehouse and 5 more	90 min
Apr 25, 2:07 AM CDT	Mesoscale Discussion	SPC	Madison	83 min
Apr 25, 7:12 AM CDT	Severe Thunderstorm Watch	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 10 more	6 hr
Apr 25, 9:35 AM CDT	Mesoscale Discussion	SPC	Acadia, Ascension, Assumption, Avoyelles, Cameron, East Baton Rouge and 27 more	115 min
Apr 25, 10:41 AM CDT	Severe Thunderstorm Watch	SPC	Ascension, Assumption, East Baton Rouge, East Feliciana, Iberville, Jefferson and 16 more	7 hr
Apr 25, 1:50 PM CDT	Mesoscale Discussion	SPC	Orleans, Saint Bernard, Saint Charles, Saint John the Baptist, Saint Tammany, Washington	85 min
Apr 25, 12:50 AM CDT	Tornado Watch	SPC	Attala, Calhoun, Carroll, Chickasaw, Choctaw, Claiborne and 25 more	6 hr
Apr 25, 4:12 AM CDT	Mesoscale Discussion	SPC	Clarke, George, Greene, Wayne	63 min
Apr 24, 10:55 PM CDT	Mesoscale Discussion	SPC	Cameron	65 min
Apr 25, 2:48 AM CDT	Mesoscale Discussion	SPC	Atascosa, Bandera, Bexar, Caldwell, Comal, DeWitt and 17 more	87 min
Apr 25, 3:09 AM CDT	Severe Thunderstorm Watch	SPC	Atascosa, Austin, Bandera, Bastrop, Bexar, Blanco and 31 more	7 hr
Apr 25, 4:31 AM CDT	Mesoscale Discussion	SPC	Atascosa, Austin, Bandera, Bastrop, Bexar, Caldwell and 23 more	89 min
Apr 25, 6:52 AM CDT	Mesoscale Discussion	SPC	Atascosa, Brazoria, Chambers, DeWitt, Fort Bend, Frio and 11 more	83 min

Nearby

Mesoscale Discussions in Louisiana, 2015 Mesoscale Discussions in Arkansas, 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.