Alert archive / Louisiana / Tornado Watches in 2015

Tornado Watch 572

December 27, 201521 counties in Arkansas; 27 parishes in Louisiana; 24 counties in Texas

The Storm Prediction Center issued this tornado watch at Dec 27, 2015, 2:47 PM CST for 21 counties in Arkansas; 27 parishes in Louisiana; 24 counties in Texas. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued: Dec 27, 2015, 2:47 PM CST (20:47 UTC)
Expired: Dec 27, 2015, 10:00 PM CST
In force: 7 hr
Issued by: the Storm Prediction Center
Largest hail expected: 1 in
Strongest gust expected: 60 kt

All 72 counties

Arkansas County, AR, Ashley County, AR, Bradley County, AR, Calhoun County, AR, Clark County, AR, Cleveland County, AR, Columbia County, AR, Dallas County, AR, Desha County, AR, Drew County, AR, Hempstead County, AR, Howard County, AR, Jefferson County, AR, Lafayette County, AR, Lincoln County, AR, Little River County, AR, Miller County, AR, Nevada County, AR, Ouachita County, AR, Sevier County, AR, Union County, AR, Acadia Parish, LA, Allen Parish, LA, Beauregard Parish, LA, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Calcasieu Parish, LA, Caldwell Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, Evangeline Parish, LA, Grant Parish, LA, Jackson Parish, LA, Jefferson Davis Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Rapides Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Union Parish, LA, Vernon Parish, LA, Webster Parish, LA, Winn Parish, LA, Angelina County, TX, Bowie County, TX, Camp County, TX, Cass County, TX, Cherokee County, TX, Franklin County, TX, Gregg County, TX, Hardin County, TX, Harrison County, TX, Jasper County, TX, Marion County, TX, Morris County, TX, Nacogdoches County, TX, Newton County, TX, Panola County, TX, Rusk County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX, Smith County, TX, Titus County, TX, Tyler County, TX, Upshur County, TX, Wood County, TX

The radar

The Shreveport radar (KSHV), 81 km from the middle of the area, began a volume at 20:50 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes: 50%
One or more EF2 to EF5 tornadoes: 20%
Ten or more severe wind reports: 40%
One or more gusts of 65 knots or more: 10%
Ten or more severe hail reports: 20%
One or more hailstones of 2 inches or more: 10%
Six or more combined severe hail and wind reports: 80%

Warnings issued inside it

61 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Dec 27, 2:52 PM CST	Flash Flood Warning	SHV	Smith, Upshur	9 hr
Dec 27, 2:56 PM CST	Flash Flood Warning	SHV	Cherokee	6 hr
Dec 27, 3:02 PM CST	Severe Thunderstorm Warning	SHV	Union	43 min
Dec 27, 3:10 PM CST	Severe Thunderstorm Warning	SHV	Camp, Franklin, Morris, Titus, Upshur, Wood	50 min
Dec 27, 3:12 PM CST	Tornado Warning	SHV	Union	33 min
Dec 27, 3:15 PM CST	Tornado Warning	SHV	Bowie, Morris, Red River	45 min
Dec 27, 3:20 PM CST	Flash Flood Warning	SHV	Bowie, Cass, Morris	9 hr
Dec 27, 3:23 PM CST	Severe Thunderstorm Warning	LZK	Calhoun, Dallas, Ouachita	52 min
Dec 27, 3:24 PM CST	Tornado Warning	SHV	Bowie, Camp, Morris, Titus, Upshur	51 min
Dec 27, 3:25 PM CST	Tornado Warning	SHV	Bowie, Camp, Franklin, Morris, Red River, Titus and 2 more	50 min
Dec 27, 3:29 PM CST	Tornado Warning	SHV	Hempstead, Lafayette, Nevada	31 min
Dec 27, 3:37 PM CST	Severe Thunderstorm Warning	LZK	Calhoun, Ouachita	23 min
Dec 27, 3:40 PM CST	Tornado Warning	SHV	Union	35 min
Dec 27, 3:43 PM CST	Tornado Warning	LZK	Calhoun, Ouachita	47 min
Dec 27, 3:52 PM CST	Tornado Warning Tornado observed	SHV	Hempstead, Nevada	23 min
Dec 27, 3:59 PM CST	Tornado Warning	SHV	Columbia, Lafayette	31 min
Dec 27, 4:10 PM CST	Tornado Warning	SHV	Union	35 min
Dec 27, 4:13 PM CST	Tornado Warning	SHV	Hempstead, Nevada	32 min
Dec 27, 4:15 PM CST	Tornado Warning	LZK	Calhoun, Dallas	45 min
Dec 27, 4:17 PM CST	Severe Thunderstorm Warning	SHV	Bowie, Cass, Morris, Red River, Titus	43 min
Dec 27, 4:23 PM CST	Severe Thunderstorm Warning	LZK	Clark, Pike	52 min
Dec 27, 4:26 PM CST	Tornado Warning	LZK	Bradley	49 min
Dec 27, 4:26 PM CST	Tornado Warning	SHV	Columbia, Nevada	34 min
Dec 27, 4:35 PM CST	Tornado Warning	SHV	Howard, Sevier	40 min
Dec 27, 4:37 PM CST	Tornado Warning	SHV	Harrison, Marion	23 min
Dec 27, 4:39 PM CST	Flash Flood Warning	SHV	Gregg, Harrison, Marion, Rusk	6 hr
Dec 27, 4:46 PM CST	Severe Thunderstorm Warning	SHV	Little River	59 min
Dec 27, 4:47 PM CST	Tornado Warning	LZK	Cleveland, Dallas	29 min
Dec 27, 4:58 PM CST	Tornado Warning Tornado observed	SHV	Nevada	17 min
Dec 27, 5:01 PM CST	Tornado Warning Tornado observed	SHV	Cass, Marion	29 min
Dec 27, 5:12 PM CST	Tornado Warning	LZK	Bradley, Cleveland	48 min
Dec 27, 5:22 PM CST	Tornado Warning	SHV	Miller	23 min
Dec 27, 5:29 PM CST	Severe Thunderstorm Warning	SHV	Hempstead, Howard, Little River, Miller, Sevier	46 min
Dec 27, 5:42 PM CST	Flash Flood Warning	LZK	Clark, Conway, Faulkner, Garland, Hot Spring, Montgomery and 6 more	6 hr
Dec 27, 5:42 PM CST	Tornado Warning	SHV	Miller	33 min
Dec 27, 5:44 PM CST	Flash Flood Warning	LZK	Calhoun, Cleveland, Dallas, Faulkner, Grant, Hot Spring and 6 more	6 hr
Dec 27, 5:54 PM CST	Tornado Warning	LZK	Cleveland, Lincoln	36 min
Dec 27, 5:57 PM CST	Tornado Warning	SHV	Harrison, Panola, Rusk	48 min
Dec 27, 6:07 PM CST	Flash Flood Warning	SHV	Hempstead, Miller	6 hr
Dec 27, 6:20 PM CST	Flash Flood Warning	SHV	Nacogdoches	6 hr
Dec 27, 6:22 PM CST	Tornado Warning	SHV	Harrison, Marion	23 min
Dec 27, 6:30 PM CST	Flash Flood Warning	SHV	Angelina	6 hr
Dec 27, 6:43 PM CST	Flash Flood Warning	SHV	Panola, Shelby	6 hr
Dec 27, 6:46 PM CST	Flash Flood Warning	SHV	Lafayette, Nevada	6 hr
Dec 27, 6:47 PM CST	Severe Thunderstorm Warning	LZK	Cleveland, Jefferson, Lincoln	28 min
Dec 27, 6:47 PM CST	Tornado Warning	SHV	Lafayette, Miller	28 min
Dec 27, 7:14 PM CST	Tornado Warning	SHV	Hempstead, Lafayette, Miller, Nevada	31 min
Dec 27, 7:14 PM CST	Tornado Warning	SHV	Bienville, Red River	31 min
Dec 27, 7:25 PM CST	Tornado Warning	SHV	Cass, Marion	35 min
Dec 27, 7:32 PM CST	Tornado Warning	SHV	Lafayette	43 min
Dec 27, 7:43 PM CST	Flash Flood Warning	SHV	Camp, Franklin, Red River, Titus, Wood	4 hr
Dec 27, 7:49 PM CST	Flash Flood Warning	SHV	Sabine, San Augustine	6 hr
Dec 27, 8:09 PM CST	Tornado Warning	SHV	Caddo	51 min
Dec 27, 8:19 PM CST	Tornado Warning	SHV	Bossier, Caddo	26 min
Dec 27, 8:33 PM CST	Tornado Warning	SHV	Columbia	27 min
Dec 27, 8:48 PM CST	Tornado Warning	SHV	Lafayette, Miller	42 min
Dec 27, 8:57 PM CST	Tornado Warning	SHV	Columbia, Nevada	33 min
Dec 27, 9:05 PM CST	Flash Flood Warning	SHV	Bossier, Caddo, De Soto	3 hr
Dec 27, 9:46 PM CST	Flash Flood Warning	SHV	Columbia, Union	6 hr
Dec 27, 9:56 PM CST	Flash Flood Warning	SHV	Bienville, Claiborne, Red River, Webster	6 hr
Dec 27, 10:00 PM CST	Severe Thunderstorm Warning	SHV	Bossier	30 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Shreveport, LA (KBAD), launched 12:00Z, 8.8 hours before the alert went out and 72 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Dec 26, 7:32 PM CST	Mesoscale Discussion	SPC	Crawford, Sebastian	88 min
Dec 26, 11:27 PM CST	Mesoscale Discussion	SPC	Boone, Crawford, Franklin, Johnson, Logan, Madison and 8 more	2 hr
Dec 27, 5:44 AM CST	Mesoscale Discussion	SPC	Little River, Sevier	3 hr
Dec 27, 8:56 AM CST	Tornado Watch	SPC	Hempstead, Howard, Lafayette, Little River, Miller, Sevier	10 hr
Dec 27, 12:45 PM CST	Mesoscale Discussion	SPC	Hempstead, Howard, Lafayette, Little River, Miller, Sevier	2 hr
Dec 27, 12:47 PM CST	Mesoscale Discussion	SPC	Ashley, Bradley, Calhoun, Cleveland, Columbia, Drew and 2 more	88 min
Dec 27, 2:27 PM CST	Mesoscale Discussion	SPC	Ashley, Bradley, Calhoun, Cleveland, Columbia, Dallas and 7 more	63 min
Dec 27, 4:55 PM CST	Mesoscale Discussion	SPC	Ashley, Bradley, Calhoun, Cleveland, Columbia, Dallas and 8 more	2 hr
Dec 27, 3:15 PM CST	Mesoscale Discussion	SPC	East Carroll, East Feliciana, Madison, Saint Helena, Tensas, Washington	90 min
Dec 26, 8:09 PM CST	Mesoscale Discussion	SPC	Borden, Callahan, Coke, Coleman, Concho, Crockett and 21 more	2 hr
Dec 26, 8:58 PM CST	Severe Thunderstorm Watch	SPC	Bandera, Crockett, Edwards, Gillespie, Kerr, Kimble and 11 more	7 hr
Dec 26, 11:21 PM CST	Mesoscale Discussion	SPC	Armstrong, Bailey, Briscoe, Carson, Castro, Cochran and 17 more	5 hr
Dec 26, 11:48 PM CST	Mesoscale Discussion	SPC	Concho, Edwards, Gillespie, Kerr, Kimble, Kinney and 11 more	87 min
Dec 27, 3:38 AM CST	Mesoscale Discussion	SPC	Hardeman	6 hr
Dec 27, 4:36 AM CST	Mesoscale Discussion	SPC	Carson, Dallam, Deaf Smith, Gray, Hansford, Hartley and 11 more	6 hr
Dec 27, 5:15 AM CST	Mesoscale Discussion	SPC	Andrews, Cochran, Crane, Culberson, Ector, Gaines and 10 more	5 hr
Dec 27, 9:50 AM CST	Mesoscale Discussion	SPC	Baylor, Childress, Coke, Cottle, Crockett, Dickens and 25 more	6 hr
Dec 27, 11:24 AM CST	Mesoscale Discussion	SPC	Andrews, Bailey, Borden, Castro, Cochran, Crane and 24 more	6 hr
Dec 27, 12:04 PM CST	Mesoscale Discussion	SPC	Archer, Bosque, Clay, Collin, Comanche, Cooke and 24 more	2 hr
Dec 27, 3:19 PM CST	Mesoscale Discussion	SPC	Brazoria, Chambers, Fort Bend, Galveston, Harris, Houston and 7 more	116 min
Dec 27, 3:55 PM CST	Mesoscale Discussion	SPC	Archer, Baylor, Callahan, Childress, Coke, Coleman and 31 more	4 hr

Nearby

Tornado Watches in Louisiana, 2015 Tornado Watches in Texas, 2015 Tornado Watches in Arkansas, 2015 Every tornado watch 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.