Alert archive / Louisiana / Mesoscale Discussions in 2015

Mesoscale Discussion 434

April 24, 201513 parishes in Louisiana; 4 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 24, 2015, 11:53 AM CDT for 13 parishes in Louisiana; 4 counties in Texas. It was in force for 97 min.

The area

The outline as issued.

The facts

Issued: Apr 24, 2015, 11:53 AM CDT (16:53 UTC)
Expired: Apr 24, 2015, 1:30 PM CDT
In force: 97 min
Issued by: the Storm Prediction Center
Chance of a watch: 60%

Counties Acadia Parish, LA, Allen Parish, LA, Assumption Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Vermilion Parish, LA, Hardin County, TX, Jefferson County, TX, Newton County, TX, Orange County, TX

The radar

The Lake Charles radar (KLCH), 5 km from the middle of the area, began a volume at 16:53 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 watches that followed

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

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 4.9 hours before the alert went out and 6 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: 1123 J/kg
Mixed-layer CIN: -100 J/kg
Mixed-layer LCL: 692 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: 104 m²/s²
0-3 km storm-relative helicity: 111 m²/s²
Significant tornado parameter: 0.4
Supercell composite: 4.2

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, 10:29 AM CDT	Mesoscale Discussion	SPC	Allen, Beauregard, Calcasieu, Jefferson Davis	91 min
Apr 24, 12:18 PM CDT	Tornado Watch	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 10 more	5 hr
Apr 24, 1:58 PM CDT	Mesoscale Discussion	SPC	Acadia, Ascension, Assumption, Cameron, East Baton Rouge, Iberia and 15 more	92 min
Apr 24, 3:15 PM CDT	Tornado Watch	SPC	Ascension, Assumption, Iberville, Jefferson, Lafourche, Orleans and 6 more	5 hr
Apr 24, 3:58 PM CDT	Mesoscale Discussion	SPC	Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 15 more	92 min
Apr 24, 4:45 PM CDT	Tornado Watch	SPC	Bienville, Bossier, Caddo, Claiborne, De Soto, Jackson and 7 more	5 hr
Apr 23, 9:34 PM CDT	Mesoscale Discussion	SPC	Bandera, Dimmit, Edwards, Frio, Jim Hogg, Kinney and 10 more	56 min
Apr 24, 2:36 AM CDT	Mesoscale Discussion	SPC	Dimmit, La Salle, McMullen, Webb, Zavala	84 min
Apr 24, 3:01 AM CDT	Severe Thunderstorm Watch	SPC	Atascosa, Dimmit, Frio, La Salle, Live Oak, McMullen and 5 more	4 hr
Apr 24, 5:41 AM CDT	Mesoscale Discussion	SPC	Atascosa, Bandera, Dimmit, Duval, Edwards, Frio and 10 more	94 min
Apr 24, 11:12 AM CDT	Mesoscale Discussion	SPC	Bosque, Brown, Callahan, Coke, Coleman, Collin and 43 more	2 hr
Apr 24, 12:56 PM CDT	Mesoscale Discussion	SPC	Childress, Collingsworth, Cottle, Crosby, Dickens, Foard and 3 more	94 min
Apr 24, 2:10 PM CDT	Tornado Watch	SPC	Anderson, Bell, Bosque, Brown, Callahan, Coke and 52 more	8 hr
Apr 24, 4:56 PM CDT	Mesoscale Discussion	SPC	Atascosa, Dimmit, Duval, Frio, Jim Hogg, Kinney and 9 more	94 min
Apr 24, 6:01 PM CDT	Mesoscale Discussion	SPC	Dallas, Ellis, Erath, Hood, Johnson, Kaufman and 3 more	59 min
Apr 24, 6:53 PM CDT	Severe Thunderstorm Watch	SPC	Atascosa, Bee, Brooks, Cameron, DeWitt, Dimmit and 19 more	6 hr

Nearby

Mesoscale Discussions in Louisiana, 2015 Mesoscale Discussions in Texas, 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.