Alert archive / Louisiana / Mesoscale Discussions in 2019

Mesoscale Discussion 271

April 6, 201917 parishes in Louisiana; 16 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 6, 2019, 7:44 PM CDT for 17 parishes in Louisiana; 16 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Apr 6, 2019, 7:44 PM CDT (00:44 UTC)
Expired
Apr 6, 2019, 9:45 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 33 counties

Bienville Parish, LA, Caldwell Parish, LA, De Soto Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Union Parish, LA, Vernon Parish, LA, Winn Parish, LA, Angelina County, TX, Brazos County, TX, Burleson County, TX, Grimes County, TX, Houston County, TX, Lee County, TX, Madison County, TX, Nacogdoches County, TX, Polk County, TX, Sabine County, TX, San Augustine County, TX, San Jacinto County, TX, Shelby County, TX, Trinity County, TX, Tyler County, TX, Walker County, TX

The radar

The Ft Polk radar (KPOE), 120 km from the middle of the area, began a volume at 00:48 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 (KBAD), launched 00:00Z, 0.7 hours before the alert went out and 139 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 2019-04-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 90 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 2019-04-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -60 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
90 J/kg
Mixed-layer CIN
-72 J/kg
Mixed-layer LCL
898 m above ground
0-6 km bulk shear
52 kt
0-1 km storm-relative helicity
-60 m²/s²
0-3 km storm-relative helicity
93 m²/s²
Significant tornado parameter
-0.0
Supercell composite
-0.5

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 7, 5:29 AM CDTMesoscale DiscussionSPCBienville, Bossier, Caddo, Claiborne, De Soto, Lincoln and 3 more2 hr
Apr 7, 12:27 PM CDTMesoscale DiscussionSPCAcadia, Allen, Avoyelles, Beauregard, Bienville, Calcasieu and 24 more93 min
Apr 7, 1:11 PM CDTSevere Thunderstorm WatchSPCAcadia, Allen, Avoyelles, Beauregard, Bienville, Bossier and 24 more6 hr
Apr 7, 1:13 PM CDTMesoscale DiscussionSPCEast Carroll, Madison, Morehouse, Richland, West Carroll2 hr
Apr 7, 2:49 PM CDTMesoscale DiscussionSPCAcadia, Allen, Beauregard, Bienville, Calcasieu, Caldwell and 17 more86 min
Apr 7, 3:41 PM CDTSevere Thunderstorm WatchSPCCatahoula, Concordia, East Carroll, Franklin, Madison, Morehouse and 3 more6 hr
Apr 7, 6:44 PM CDTMesoscale DiscussionSPCAscension, East Baton Rouge, East Carroll, East Feliciana, Livingston, Madison and 6 more2 hr
Apr 7, 1:00 AM CDTMesoscale DiscussionSPCAransas, Atascosa, Bee, Bexar, DeWitt, Dimmit and 19 more90 min
Apr 7, 1:55 AM CDTSevere Thunderstorm WatchSPCAransas, Atascosa, Bee, Bexar, Brooks, Calhoun and 32 more7 hr
Apr 7, 6:41 AM CDTMesoscale DiscussionSPCAransas, Atascosa, Austin, Bastrop, Bee, Bexar and 38 more94 min
Apr 7, 7:11 AM CDTSevere Thunderstorm WatchSPCAustin, Brazoria, Brazos, Burleson, Chambers, Colorado and 17 more8 hr
Apr 7, 11:13 AM CDTMesoscale DiscussionSPCAustin, Brazoria, Calhoun, Colorado, Fort Bend, Galveston and 13 more92 min

Nearby

Mesoscale Discussions in Louisiana, 2019Mesoscale Discussions in Texas, 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.