Alert archive / Louisiana / Mesoscale Discussions in 2020

Mesoscale Discussion 364

April 12, 202012 parishes in Louisiana; Amite County, Pike County, Walthall County, Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 12, 2020, 5:27 PM CDT for 12 parishes in Louisiana; Amite County, Pike County, Walthall County, Mississippi. It was in force for 63 min.

The area

The outline as issued.

The facts

Issued
Apr 12, 2020, 5:27 PM CDT (22:27 UTC)
Expired
Apr 12, 2020, 6:30 PM CDT
In force
63 min
Issued by
the Storm Prediction Center

Counties Ascension Parish, LA, Assumption Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Iberville Parish, LA, Livingston Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint Martin Parish, LA, Tangipahoa Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, Amite County, MS, Pike County, MS, Walthall County, MS

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 10.5 hours before the alert went out and 129 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-pSkew-T log-p diagram, Slidell Radar S, LA at 12:00Z on 2020-04-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1968 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Slidell Radar S, LA at 12:00Z on 2020-04-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 302 square meters per square second.1939587897117Sfc1 km3 km6 km9 kmRMLM
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
1968 J/kg
Mixed-layer CIN
-74 J/kg
Mixed-layer LCL
480 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
302 m²/s²
0-3 km storm-relative helicity
580 m²/s²
Significant tornado parameter
2.7
Supercell composite
9.4

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.

IssuedProductOfficeCountiesLasted
Apr 12, 5:52 AM CDTTornado WatchSPCBienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 11 more8 hr
Apr 12, 7:18 AM CDTMesoscale DiscussionSPCBienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 13 more87 min
Apr 12, 9:30 AM CDTMesoscale DiscussionSPCBienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 11 more90 min
Apr 12, 10:24 AM CDTMesoscale DiscussionSPCCatahoula, Concordia, East Carroll, Franklin, Madison, Morehouse and 3 more96 min
Apr 12, 10:41 AM CDTTornado Watch PDSSPCCatahoula, Concordia, East Carroll, Franklin, Madison, Morehouse and 3 more10 hr
Apr 12, 12:03 PM CDTMesoscale DiscussionSPCEast Carroll, Franklin, Madison, Morehouse, Richland, West Carroll87 min
Apr 12, 1:02 PM CDTMesoscale DiscussionSPCAscension, Assumption, East Baton Rouge, East Feliciana, Iberville, Livingston and 12 more118 min
Apr 12, 1:24 PM CDTTornado WatchSPCAcadia, Ascension, Assumption, East Baton Rouge, East Feliciana, Iberia and 16 more9 hr
Apr 12, 5:44 PM CDTMesoscale DiscussionSPCMadison, Tensas91 min
Apr 12, 5:59 PM CDTSevere Thunderstorm WatchSPCBienville, Bossier, Caddo, Caldwell, Claiborne, Jackson and 5 more4 hr
Apr 12, 6:14 PM CDTMesoscale DiscussionSPCBienville, Bossier, Caddo, Claiborne, Lincoln, Red River and 1 more91 min
Apr 12, 1:40 PM CDTMesoscale DiscussionSPCAttala, Choctaw, Hinds, Holmes, Kemper, Lauderdale and 10 more95 min
Apr 12, 3:38 PM CDTMesoscale DiscussionSPCCopiah, Covington, Jasper, Jefferson Davis, Kemper, Lauderdale and 14 more97 min
Apr 12, 3:52 PM CDTMesoscale DiscussionSPCCovington, Jefferson Davis, Jones, Marion23 min
Apr 12, 3:53 PM CDTMesoscale DiscussionSPCGreene, Perry, Wayne97 min
Apr 12, 4:26 PM CDTMesoscale DiscussionSPCCovington, Jasper, Jones34 min
Apr 12, 4:38 PM CDTTornado Watch PDSSPCGeorge, Greene, Perry, Stone, Wayne7 hr
Apr 12, 4:54 PM CDTMesoscale DiscussionSPCClarke, Covington, Jasper, Jefferson Davis, Jones, Wayne66 min

Nearby

Mesoscale Discussions in Louisiana, 2020Mesoscale Discussions in Mississippi, 2020Every 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.