Alert archive / Louisiana / Mesoscale Discussions in 2020

Mesoscale Discussion 349

April 12, 202017 parishes in Louisiana; San Augustine County, Shelby County, Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 12, 2020, 9:30 AM CDT for 17 parishes in Louisiana; San Augustine County, Shelby County, Texas. It was in force for 90 min.

The area

The outline as issued.

The facts

Issued
Apr 12, 2020, 9:30 AM CDT (14:30 UTC)
Expired
Apr 12, 2020, 11:00 AM CDT
In force
90 min
Issued by
the Storm Prediction Center

Counties Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Caldwell Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Sabine Parish, LA, Union Parish, LA, Webster Parish, LA, Winn Parish, LA, San Augustine County, TX, Shelby County, TX

The radar

The Shreveport radar (KSHV), 54 km from the middle of the area, began a volume at 14:32 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 (KSHV), launched 12:00Z, 2.5 hours before the alert went out and 57 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, Shreveport, LA at 12:00Z on 2020-04-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 605 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, Shreveport, LA at 12:00Z on 2020-04-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 255 square meters per square second.1939587897Sfc1 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
605 J/kg
Mixed-layer CIN
-277 J/kg
Mixed-layer LCL
681 m above ground
0-6 km bulk shear
59 kt
0-1 km storm-relative helicity
255 m²/s²
0-3 km storm-relative helicity
308 m²/s²
Significant tornado parameter
0.0
Supercell composite
3.1

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, 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, 5:27 PM CDTMesoscale DiscussionSPCAscension, Assumption, East Baton Rouge, East Feliciana, Iberville, Livingston and 6 more63 min
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 11, 7:51 PM CDTMesoscale DiscussionSPCEdwards, Kinney, Real, Sutton, Uvalde, Val Verde84 min
Apr 11, 8:37 PM CDTTornado WatchSPCAtascosa, Bandera, Bastrop, Bexar, Blanco, Caldwell and 23 more5 hr
Apr 11, 9:23 PM CDTMesoscale DiscussionSPCArcher, Baylor, Callahan, Clay, Coke, Coleman and 23 more67 min
Apr 11, 11:03 PM CDTMesoscale DiscussionSPCAtascosa, Bandera, Bexar, Caldwell, Comal, DeWitt and 12 more57 min
Apr 12, 1:37 AM CDTMesoscale DiscussionSPCBandera, Bell, Blanco, Bosque, Brazos, Brown and 44 more113 min
Apr 12, 1:59 AM CDTTornado WatchSPCBandera, Bastrop, Bell, Bexar, Blanco, Bosque and 37 more6 hr
Apr 12, 4:15 AM CDTMesoscale DiscussionSPCBandera, Bastrop, Bell, Blanco, Bosque, Brown and 24 more90 min
Apr 12, 1:10 PM CDTMesoscale DiscussionSPCCamp, Collin, Cooke, Dallas, Delta, Denton and 17 more95 min
Apr 12, 2:51 PM CDTSevere Thunderstorm WatchSPCBowie, Camp, Cass, Delta, Fannin, Franklin and 11 more5 hr

Nearby

Mesoscale Discussions in Louisiana, 2020Mesoscale Discussions in Texas, 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; radar from the NEXRAD Level II archive.