Alert archive / Louisiana / Mesoscale Discussions in 2014

Mesoscale Discussion 437

April 27, 20144 counties in Arkansas; 6 parishes in Louisiana; 6 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Apr 27, 2014, 8:09 PM CDT for 4 counties in Arkansas; 6 parishes in Louisiana; 6 counties in Texas. It was in force for 66 min.

The area

The outline as issued.

The facts

Issued
Apr 27, 2014, 8:09 PM CDT (01:09 UTC)
Expired
Apr 27, 2014, 9:15 PM CDT
In force
66 min
Issued by
the Storm Prediction Center

Counties Columbia County, AR, Lafayette County, AR, Miller County, AR, Union County, AR, Bossier Parish, LA, Caddo Parish, LA, Claiborne Parish, LA, Lincoln Parish, LA, Union Parish, LA, Webster Parish, LA, Camp County, TX, Cass County, TX, Harrison County, TX, Marion County, TX, Morris County, TX, Upshur County, TX

The radar

The Shreveport radar (KSHV), 48 km from the middle of the area, began a volume at 01:09 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, 1.2 hours before the alert went out and 44 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 2014-04-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1893 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 2014-04-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 169 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
1893 J/kg
Mixed-layer CIN
-96 J/kg
Mixed-layer LCL
1351 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
169 m²/s²
0-3 km storm-relative helicity
215 m²/s²
Significant tornado parameter
0.9
Supercell composite
5.6

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 27, 7:15 PM CDTMesoscale DiscussionSPCFaulkner30 min
Apr 27, 7:29 PM CDTMesoscale DiscussionSPCClay, Craighead, Crittenden, Cross, Greene, Mississippi and 1 more91 min
Apr 27, 7:53 PM CDTTornado WatchSPCClay, Craighead, Crittenden, Cross, Greene, Lawrence and 4 more6 hr
Apr 27, 8:43 PM CDTMesoscale DiscussionSPCClark, Clay, Cleburne, Cleveland, Conway, Craighead and 45 more62 min
Apr 27, 9:59 PM CDTMesoscale DiscussionSPCCalhoun, Clark, Cleburne, Cleveland, Columbia, Conway and 36 more91 min
Apr 27, 10:33 PM CDTTornado WatchSPCArkansas, Bradley, Calhoun, Clark, Cleveland, Conway and 27 more7 hr
Apr 27, 11:08 PM CDTTornado WatchSPCColumbia, Hempstead, Howard, Lafayette, Little River, Miller and 3 more6 hr
Apr 27, 11:21 PM CDTMesoscale DiscussionSPCArkansas, Baxter, Boone, Bradley, Calhoun, Carroll and 38 more84 min
Apr 27, 11:41 PM CDTMesoscale DiscussionSPCClay, Craighead, Crittenden, Cross, Greene, Mississippi and 2 more94 min
Apr 28, 1:43 AM CDTTornado WatchSPCClay, Craighead, Crittenden, Cross, Greene, Lawrence and 6 more8 hr
Apr 28, 2:50 AM CDTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Cleveland and 25 more115 min
Apr 28, 4:21 AM CDTMesoscale DiscussionSPCAshley, Bradley, Chicot, Columbia, Drew, Union54 min
Apr 28, 4:40 AM CDTTornado WatchSPCAshley, Chicot, Union7 hr
Apr 28, 7:16 AM CDTMesoscale DiscussionSPCChicot89 min
Apr 28, 9:53 AM CDTMesoscale DiscussionSPCChicot97 min
Apr 27, 10:45 PM CDTMesoscale DiscussionSPCBossier, Caddo, De Soto, Sabine2 hr
Apr 28, 12:05 PM CDTMesoscale DiscussionSPCCaldwell, Catahoula, Concordia, East Carroll, Franklin, LaSalle and 5 more115 min
Apr 28, 12:39 PM CDTTornado Watch PDSSPCCatahoula, Concordia, East Carroll, Franklin, Madison, Richland and 2 more8 hr
Apr 28, 3:55 PM CDTMesoscale DiscussionSPCAllen, Beauregard, Evangeline, Jefferson Davis, Rapides, Vernon2 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.