Alert archive / Louisiana / Severe Thunderstorm Watches in 2014

Severe Thunderstorm Watch 9

February 20, 20144 states

The Storm Prediction Center issued this severe thunderstorm watch at Feb 20, 2014, 12:47 PM CST for 4 states. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued: Feb 20, 2014, 12:47 PM CST (18:47 UTC)
Expired: Feb 20, 2014, 8:00 PM CST
In force: 7 hr
Issued by: the Storm Prediction Center
Largest hail expected: 1.5 in
Strongest gust expected: 60 kt

All 82 counties

Arkansas County, AR, Ashley County, AR, Bradley County, AR, Calhoun County, AR, Chicot County, AR, Cleveland County, AR, Columbia County, AR, Dallas County, AR, Desha County, AR, Drew County, AR, Grant County, AR, Independence County, AR, Jackson County, AR, Jefferson County, AR, Lafayette County, AR, Lincoln County, AR, Lonoke County, AR, Monroe County, AR, Ouachita County, AR, Prairie County, AR, Sharp County, AR, Union County, AR, White County, AR, Woodruff County, AR, Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, Claiborne Parish, LA, Concordia Parish, LA, De Soto Parish, LA, East Carroll Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Rapides Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Tensas Parish, LA, Union Parish, LA, Vernon Parish, LA, Webster Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Bolivar County, MS, Carroll County, MS, Grenada County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Leflore County, MS, Montgomery County, MS, Sharkey County, MS, Sunflower County, MS, Warren County, MS, Washington County, MS, Webster County, MS, Yazoo County, MS, Angelina County, TX, Houston County, TX, Jasper County, TX, Nacogdoches County, TX, Newton County, TX, Panola County, TX, Polk County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX, Trinity County, TX, Tyler County, TX

The radar

The Shreveport radar (KSHV), 80 km from the middle of the area, began a volume at 18:50 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: 20%
One or more EF2 to EF5 tornadoes: 5%
Ten or more severe wind reports: 50%
One or more gusts of 65 knots or more: 20%
Ten or more severe hail reports: 20%
One or more hailstones of 2 inches or more: 20%
Six or more combined severe hail and wind reports: 80%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Feb 20, 1:06 PM CST	Severe Thunderstorm Warning	SHV	Bossier, Claiborne, Webster	39 min
Feb 20, 1:15 PM CST	Severe Thunderstorm Warning	SHV	Bossier, Caddo, De Soto, Webster	45 min
Feb 20, 1:45 PM CST	Severe Thunderstorm Warning	SHV	Union	60 min
Feb 20, 1:59 PM CST	Severe Thunderstorm Warning	SHV	Bienville, Bossier, Caddo, Claiborne, De Soto, Lincoln and 2 more	61 min
Feb 20, 2:09 PM CST	Severe Thunderstorm Warning	LZK	Desha, Drew, Lincoln	36 min
Feb 20, 2:34 PM CST	Severe Thunderstorm Warning	LZK	Arkansas, Desha, Jefferson, Lincoln	41 min
Feb 20, 2:55 PM CST	Severe Thunderstorm Warning	SHV	Angelina, Nacogdoches	65 min
Feb 20, 3:29 PM CST	Severe Thunderstorm Warning	LZK	Desha, Drew	31 min
Feb 20, 4:05 PM CST	Severe Thunderstorm Warning	SHV	Angelina, San Augustine	25 min
Feb 20, 4:06 PM CST	Severe Thunderstorm Warning	JAN	Bolivar	54 min
Feb 20, 5:06 PM CST	Severe Thunderstorm Warning	JAN	Bolivar	39 min
Feb 20, 5:19 PM CST	Severe Thunderstorm Warning	JAN	Chicot	41 min
Feb 20, 5:39 PM CST	Severe Thunderstorm Warning	JAN	Humphreys, Leflore, Sunflower	51 min
Feb 20, 5:52 PM CST	Tornado Warning	JAN	Leflore, Sunflower	53 min
Feb 20, 5:57 PM CST	Severe Thunderstorm Warning	LCH	Hardin, Jasper, Newton, Tyler	63 min
Feb 20, 6:15 PM CST	Severe Thunderstorm Warning	JAN	Carroll, Grenada, Leflore	45 min
Feb 20, 7:46 PM CST	Severe Thunderstorm Warning	JAN	Choctaw, Montgomery, Webster	44 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, 6.8 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: 22 J/kg
Mixed-layer CIN: -480 J/kg
Mixed-layer LCL: 671 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 420 m²/s²
0-3 km storm-relative helicity: 590 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 20, 11:01 AM CST	Mesoscale Discussion	SPC	Arkansas, Ashley, Bradley, Calhoun, Chicot, Cleveland and 12 more	119 min
Feb 20, 1:45 PM CST	Mesoscale Discussion	SPC	Clay, Craighead, Crittenden, Cross, Greene, Lee and 4 more	2 hr
Feb 20, 2:23 PM CST	Tornado Watch	SPC	Clay, Craighead, Crittenden, Cross, Greene, Lawrence and 6 more	7 hr
Feb 20, 3:11 PM CST	Mesoscale Discussion	SPC	Ashley, Chicot, Desha	94 min
Feb 20, 5:29 PM CST	Mesoscale Discussion	SPC	Crittenden, Mississippi	46 min
Feb 20, 5:55 PM CST	Mesoscale Discussion	SPC	Acadia, Allen, Ascension, Avoyelles, Beauregard, Caldwell and 26 more	35 min

Nearby

Severe Thunderstorm Watches in Louisiana, 2014 Severe Thunderstorm Watches in Arkansas, 2014 Severe Thunderstorm Watches in Mississippi, 2014 Every severe thunderstorm watch 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.