Alert archive / Louisiana / Mesoscale Discussions in 2014

Mesoscale Discussion 276

April 4, 2014Calhoun County, Columbia County, Union County, Arkansas; 10 parishes in Louisiana; 10 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 4, 2014, 12:55 AM CDT for Calhoun County, Columbia County, Union County, Arkansas; 10 parishes in Louisiana; 10 counties in Texas. It was in force for 95 min.

The area

The outline as issued.

The facts

Issued
Apr 4, 2014, 12:55 AM CDT (05:55 UTC)
Expired
Apr 4, 2014, 2:30 AM CDT
In force
95 min
Issued by
the Storm Prediction Center
All 23 counties

Calhoun County, AR, Columbia County, AR, Union County, AR, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, Jackson Parish, LA, Lincoln Parish, LA, Red River Parish, LA, Union Parish, LA, Webster Parish, LA, Gregg County, TX, Harrison County, TX, Henderson County, TX, Marion County, TX, Panola County, TX, Rusk County, TX, Shelby County, TX, Smith County, TX, Upshur County, TX, Van Zandt County, TX

The radar

The Shreveport radar (KSHV), 33 km from the middle of the area, began a volume at 05:56 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

Shreveport, LA (KBAD), launched 00:00Z, 5.9 hours before the alert went out and 36 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 00:00Z on 2014-04-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2253 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 00:00Z on 2014-04-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 151 square meters per square second.19395878Sfc1 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
2253 J/kg
Mixed-layer CIN
-33 J/kg
Mixed-layer LCL
988 m above ground
0-6 km bulk shear
52 kt
0-1 km storm-relative helicity
151 m²/s²
0-3 km storm-relative helicity
155 m²/s²
Significant tornado parameter
1.9
Supercell composite
6.9

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.

IssuedProductOfficeCountiesLasted
Apr 3, 7:03 PM CDTMesoscale DiscussionSPCHempstead, Howard, Lafayette, Little River, Miller, Nevada and 1 more57 min
Apr 3, 7:26 PM CDTMesoscale DiscussionSPCBaxter, Boone, Carroll, Fulton, Madison, Marion94 min
Apr 3, 8:16 PM CDTMesoscale DiscussionSPCBaxter, Clay, Cleburne, Conway, Craighead, Crittenden and 29 more59 min
Apr 3, 8:30 PM CDTTornado WatchSPCClay, Craighead, Greene, Lawrence, Mississippi, Poinsett and 1 more7 hr
Apr 3, 8:44 PM CDTMesoscale DiscussionSPCColumbia, Crawford, Franklin, Hempstead, Howard, Lafayette and 7 more31 min
Apr 3, 8:54 PM CDTTornado WatchSPCColumbia, Hempstead, Howard, Lafayette, Little River, Miller and 3 more7 hr
Apr 3, 10:45 PM CDTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Clark and 32 more60 min
Apr 3, 11:40 PM CDTMesoscale DiscussionSPCClay, Craighead, Greene, Lawrence, Mississippi, Poinsett95 min
Apr 4, 12:20 AM CDTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Cleveland and 20 more55 min
Apr 4, 12:40 AM CDTTornado WatchSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Cleveland and 16 more5 hr
Apr 4, 3:34 AM CDTSevere Thunderstorm WatchSPCAllen, Beauregard, Calcasieu, Caldwell, Cameron, De Soto and 9 more6 hr
Apr 4, 3:45 AM CDTMesoscale DiscussionSPCCaldwell, East Carroll, Franklin, Jackson, Madison, Morehouse and 4 more60 min
Apr 4, 5:04 AM CDTMesoscale DiscussionSPCAcadia, Ascension, Assumption, East Baton Rouge, East Feliciana, Iberia and 15 more116 min
Apr 4, 5:25 AM CDTSevere Thunderstorm WatchSPCAcadia, Ascension, Assumption, Avoyelles, Catahoula, Concordia and 30 more7 hr
Apr 4, 5:28 AM CDTMesoscale DiscussionSPCCatahoula, Concordia, Madison, Tensas92 min
Apr 4, 5:49 AM CDTMesoscale DiscussionSPCAllen, Beauregard, Calcasieu, Caldwell, De Soto, Franklin and 8 more56 min
Apr 4, 7:22 AM CDTMesoscale DiscussionSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Calcasieu and 26 more83 min
Apr 4, 10:12 AM CDTMesoscale DiscussionSPCAcadia, Ascension, Assumption, Avoyelles, Cameron, Catahoula and 28 more63 min
Apr 3, 7:18 PM CDTMesoscale DiscussionSPCBandera, Bastrop, Bexar, Blanco, Burnet, Caldwell and 11 more57 min
Apr 3, 7:35 PM CDTSevere Thunderstorm WatchSPCBandera, Bastrop, Blanco, Burnet, Caldwell, Comal and 9 more2 hr
Apr 3, 11:52 PM CDTSevere Thunderstorm WatchSPCAtascosa, Bee, Dimmit, Duval, Frio, Goliad and 12 more8 hr
Apr 4, 2:40 AM CDTMesoscale DiscussionSPCAngelina, Austin, Brazoria, Brazos, Burleson, Chambers and 26 more2 hr
Apr 4, 2:58 AM CDTMesoscale DiscussionSPCAtascosa, Bee, Dimmit, Frio, Karnes, La Salle and 3 more92 min
Apr 4, 6:12 AM CDTMesoscale DiscussionSPCBee, Brooks, Cameron, Duval, Hidalgo, Jim Hogg and 12 more3 hr

Nearby

Mesoscale Discussions in Louisiana, 2014Mesoscale Discussions in Texas, 2014Mesoscale Discussions in Arkansas, 2014Every mesoscale discussion in 2014

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.