Alert archive / Louisiana / Mesoscale Discussions in 2015

Mesoscale Discussion 2090

December 27, 201514 counties in Arkansas; 19 parishes in Louisiana; 9 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Dec 27, 2015, 4:55 PM CST for 14 counties in Arkansas; 19 parishes in Louisiana; 9 counties in Texas. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Dec 27, 2015, 4:55 PM CST (22:55 UTC)
Expired
Dec 27, 2015, 7:00 PM CST
In force
2 hr
Issued by
the Storm Prediction Center
All 42 counties

Ashley County, AR, Bradley County, AR, Calhoun County, AR, Cleveland County, AR, Columbia County, AR, Dallas County, AR, Desha County, AR, Drew County, AR, Lafayette County, AR, Lincoln County, AR, Miller County, AR, Nevada County, AR, Ouachita County, AR, Union County, AR, 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, 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, Webster Parish, LA, Winn Parish, LA, Cass County, TX, Harrison County, TX, Marion County, TX, Nacogdoches County, TX, Panola County, TX, Rusk County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX

The radar

The Shreveport radar (KSHV), 49 km from the middle of the area, began a volume at 22:59 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 12:00Z, 10.9 hours before the alert went out and 40 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 2015-12-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 625 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 2015-12-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 350 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
625 J/kg
Mixed-layer CIN
-20 J/kg
Mixed-layer LCL
707 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
350 m²/s²
0-3 km storm-relative helicity
426 m²/s²
Significant tornado parameter
1.1
Supercell composite
8.3

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
Dec 26, 7:32 PM CSTMesoscale DiscussionSPCCrawford, Sebastian88 min
Dec 26, 11:27 PM CSTMesoscale DiscussionSPCBoone, Crawford, Franklin, Johnson, Logan, Madison and 8 more2 hr
Dec 27, 5:44 AM CSTMesoscale DiscussionSPCLittle River, Sevier3 hr
Dec 27, 8:56 AM CSTTornado WatchSPCHempstead, Howard, Lafayette, Little River, Miller, Sevier10 hr
Dec 27, 12:45 PM CSTMesoscale DiscussionSPCHempstead, Howard, Lafayette, Little River, Miller, Sevier2 hr
Dec 27, 12:47 PM CSTMesoscale DiscussionSPCAshley, Bradley, Calhoun, Cleveland, Columbia, Drew and 2 more88 min
Dec 27, 2:27 PM CSTMesoscale DiscussionSPCAshley, Bradley, Calhoun, Cleveland, Columbia, Dallas and 7 more63 min
Dec 27, 2:47 PM CSTTornado WatchSPCArkansas, Ashley, Bradley, Calhoun, Clark, Cleveland and 15 more7 hr
Dec 27, 3:15 PM CSTMesoscale DiscussionSPCEast Carroll, East Feliciana, Madison, Saint Helena, Tensas, Washington90 min
Dec 26, 8:09 PM CSTMesoscale DiscussionSPCBorden, Callahan, Coke, Coleman, Concho, Crockett and 21 more2 hr
Dec 26, 8:58 PM CSTSevere Thunderstorm WatchSPCBandera, Crockett, Edwards, Gillespie, Kerr, Kimble and 11 more7 hr
Dec 26, 11:21 PM CSTMesoscale DiscussionSPCArmstrong, Bailey, Briscoe, Carson, Castro, Cochran and 17 more5 hr
Dec 26, 11:48 PM CSTMesoscale DiscussionSPCConcho, Edwards, Gillespie, Kerr, Kimble, Kinney and 11 more87 min
Dec 27, 3:38 AM CSTMesoscale DiscussionSPCHardeman6 hr
Dec 27, 4:36 AM CSTMesoscale DiscussionSPCCarson, Dallam, Deaf Smith, Gray, Hansford, Hartley and 11 more6 hr
Dec 27, 5:15 AM CSTMesoscale DiscussionSPCAndrews, Cochran, Crane, Culberson, Ector, Gaines and 10 more5 hr
Dec 27, 9:50 AM CSTMesoscale DiscussionSPCBaylor, Childress, Coke, Cottle, Crockett, Dickens and 25 more6 hr
Dec 27, 11:24 AM CSTMesoscale DiscussionSPCAndrews, Bailey, Borden, Castro, Cochran, Crane and 24 more6 hr
Dec 27, 12:04 PM CSTMesoscale DiscussionSPCArcher, Bosque, Clay, Collin, Comanche, Cooke and 24 more2 hr
Dec 27, 3:19 PM CSTMesoscale DiscussionSPCBrazoria, Chambers, Fort Bend, Galveston, Harris, Houston and 7 more116 min
Dec 27, 3:55 PM CSTMesoscale DiscussionSPCArcher, Baylor, Callahan, Childress, Coke, Coleman and 31 more4 hr

Nearby

Mesoscale Discussions in Louisiana, 2015Mesoscale Discussions in Arkansas, 2015Mesoscale Discussions in Texas, 2015Every mesoscale discussion in 2015

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.