Alert archive / Louisiana / Mesoscale Discussions in 2019

Mesoscale Discussion 385

April 18, 201911 counties in Arkansas; 18 parishes in Louisiana; 17 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 18, 2019, 3:51 AM CDT for 11 counties in Arkansas; 18 parishes in Louisiana; 17 counties in Texas. It was in force for 114 min.

The area

The outline as issued.

The facts

Issued
Apr 18, 2019, 3:51 AM CDT (08:51 UTC)
Expired
Apr 18, 2019, 5:45 AM CDT
In force
114 min
Issued by
the Storm Prediction Center
All 46 counties

Bradley County, AR, Calhoun County, AR, Cleveland County, AR, Columbia County, AR, Dallas County, AR, Hempstead County, AR, Lafayette County, AR, Miller County, AR, Nevada County, AR, Ouachita County, AR, Union County, AR, Beauregard Parish, LA, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, Grant Parish, LA, Jackson Parish, LA, Lincoln Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Rapides Parish, LA, Red River Parish, LA, Sabine Parish, LA, Union Parish, LA, Vernon Parish, LA, Webster Parish, LA, Winn Parish, LA, Angelina County, TX, Cass County, TX, Gregg County, TX, Hardin County, TX, Harrison County, TX, Jasper County, TX, Marion County, TX, Nacogdoches County, TX, Newton County, TX, Panola County, TX, Polk County, TX, Rusk County, TX, Sabine County, TX, San Augustine County, TX, San Jacinto County, TX, Shelby County, TX, Tyler County, TX

The radar

The Shreveport radar (KSHV), 21 km from the middle of the area, began a volume at 08:50 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

Lake Charles Mun, LA (KLCH), launched 00:00Z, 8.9 hours before the alert went out and 262 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, Lake Charles Mun, LA at 00:00Z on 2019-04-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 553 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, Lake Charles Mun, LA at 00:00Z on 2019-04-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 195 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
553 J/kg
Mixed-layer CIN
-209 J/kg
Mixed-layer LCL
597 m above ground
0-6 km bulk shear
55 kt
0-1 km storm-relative helicity
195 m²/s²
0-3 km storm-relative helicity
210 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.2

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 17, 9:20 PM CDTMesoscale DiscussionSPCBoone, Carroll, Crawford, Franklin, Garland, Howard and 15 more85 min
Apr 18, 12:54 AM CDTMesoscale DiscussionSPCColumbia, Hempstead, Lafayette, Little River, Miller, Nevada and 1 more66 min
Apr 18, 1:09 AM CDTSevere Thunderstorm WatchSPCColumbia, Hempstead, Howard, Lafayette, Little River, Miller and 2 more7 hr
Apr 18, 1:15 AM CDTMesoscale DiscussionSPCArkansas, Baxter, Clark, Clay, Cleburne, Cleveland and 40 more60 min
Apr 18, 6:36 AM CDTMesoscale DiscussionSPCAcadia, Allen, Beauregard, Bienville, Calcasieu, Cameron and 9 more84 min
Apr 18, 9:50 AM CDTMesoscale DiscussionSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Cameron and 25 more85 min
Apr 18, 10:35 AM CDTTornado WatchSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Cameron and 31 more8 hr
Apr 18, 12:42 PM CDTMesoscale DiscussionSPCAscension, East Baton Rouge, Livingston, Orleans, Saint Charles, Saint Helena and 5 more2 hr
Apr 18, 1:41 PM CDTTornado WatchSPCJefferson, Orleans, Plaquemines, Saint Bernard, Saint Tammany, Washington7 hr
Apr 18, 2:46 PM CDTMesoscale DiscussionSPCAscension, Assumption, East Baton Rouge, Iberville, Lafourche, Livingston and 10 more89 min
Apr 17, 7:18 PM CDTSevere Thunderstorm WatchSPCAtascosa, Bandera, Bastrop, Bexar, Blanco, Brown and 37 more7 hr
Apr 17, 9:30 PM CDTMesoscale DiscussionSPCBosque, Brown, Collin, Comanche, Cooke, Coryell and 27 more90 min
Apr 17, 11:52 PM CDTMesoscale DiscussionSPCAtascosa, Bastrop, Bee, Bell, Bexar, Brazos and 32 more83 min

Nearby

Mesoscale Discussions in Louisiana, 2019Mesoscale Discussions in Texas, 2019Mesoscale Discussions in Arkansas, 2019Every mesoscale discussion in 2019

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.