Alert archive / Louisiana / Tornado Watches in 2015

Tornado Watch 105

April 24, 20154 states

The Storm Prediction Center issued this tornado watch at Apr 24, 2015, 9:59 PM CDT for 4 states. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Apr 24, 2015, 9:59 PM CDT (02:59 UTC)
Expired
Apr 25, 2015, 2:19 AM CDT
In force
4 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
70 kt
All 48 counties

Ashley County, AR, Bradley County, AR, Calhoun County, AR, Chicot County, AR, Cleveland County, AR, Columbia County, AR, Desha County, AR, Drew County, AR, Lafayette County, AR, Lincoln County, AR, Union County, AR, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Caldwell Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, East Carroll Parish, LA, Franklin Parish, LA, Jackson Parish, LA, Lincoln Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Richland Parish, LA, Tensas Parish, LA, Union Parish, LA, Webster Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Bolivar County, MS, Humphreys County, MS, Issaquena County, MS, Sharkey County, MS, Sunflower County, MS, Warren County, MS, Washington County, MS, Yazoo County, MS, Cherokee County, TX, Gregg County, TX, Harrison County, TX, Marion County, TX, Nacogdoches County, TX, Panola County, TX, Rusk County, TX, Shelby County, TX, Smith County, TX

What SPC expected

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

Two or more tornadoes
40%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
50%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
10%
Six or more combined severe hail and wind reports
80%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 24, 10:05 PM CDTSevere Thunderstorm WarningLZKArkansas, Bradley, Cleveland, Desha, Drew, Jefferson and 1 more55 min
Apr 24, 10:08 PM CDTSevere Thunderstorm WarningSHVCherokee, Rusk, Smith67 min
Apr 24, 10:17 PM CDTSevere Thunderstorm WarningSHVColumbia, Hempstead, Lafayette, Nevada, Union43 min
Apr 24, 10:19 PM CDTFlash Flood WarningLZKCalhoun, Cleveland, Dallas, Grant, Ouachita2 hr
Apr 24, 10:32 PM CDTSevere Thunderstorm WarningSHVBienville, Bossier, Caddo, Claiborne, De Soto, Red River and 1 more43 min
Apr 24, 10:34 PM CDTSevere Thunderstorm WarningSHVCherokee, Nacogdoches, Panola, Rusk, Smith41 min
Apr 24, 10:45 PM CDTTornado WarningSHVUnion30 min
Apr 24, 10:52 PM CDTSevere Thunderstorm WarningSHVUnion53 min
Apr 24, 11:02 PM CDTSevere Thunderstorm WarningSHVCaddo, De Soto58 min
Apr 24, 11:23 PM CDTSevere Thunderstorm WarningJANAshley67 min
Apr 24, 11:32 PM CDTTornado WarningJANAshley47 min
Apr 24, 11:44 PM CDTFlash Flood WarningJANChicot2 hr
Apr 24, 11:46 PM CDTTornado WarningJANMorehouse34 min
Apr 24, 11:47 PM CDTSevere Thunderstorm WarningSHVOuachita, Union28 min
Apr 24, 11:57 PM CDTSevere Thunderstorm WarningJANChicot43 min
Apr 25, 12:07 AM CDTFlash Flood WarningLZKDesha, Drew, Lincoln3 hr
Apr 25, 12:09 AM CDTTornado WarningJANChicot66 min
Apr 25, 12:18 AM CDTSevere Thunderstorm WarningJANEast Carroll, Madison57 min
Apr 25, 12:39 AM CDTTornado WarningJANHumphreys, Issaquena, Sharkey, Yazoo51 min
Apr 25, 1:05 AM CDTSevere Thunderstorm WarningJANMadison55 min
Apr 25, 1:22 AM CDTTornado WarningJANMadison, Yazoo38 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 00:00Z, 3.0 hours before the alert went out and 93 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 2015-04-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 310 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 2015-04-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 317 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
310 J/kg
Mixed-layer CIN
-118 J/kg
Mixed-layer LCL
809 m above ground
0-6 km bulk shear
73 kt
0-1 km storm-relative helicity
317 m²/s²
0-3 km storm-relative helicity
428 m²/s²
Significant tornado parameter
0.5
Supercell composite
9.9

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 24, 7:46 PM CDTMesoscale DiscussionSPCColumbia, Lafayette, Miller, Union89 min
Apr 24, 9:20 PM CDTMesoscale DiscussionSPCAshley, Chicot, Columbia, Lafayette, Union55 min
Apr 24, 11:45 PM CDTMesoscale DiscussionSPCCaldwell, East Carroll, Franklin, Jackson, Madison, Morehouse and 5 more90 min
Apr 25, 2:07 AM CDTMesoscale DiscussionSPCMadison83 min
Apr 25, 7:12 AM CDTSevere Thunderstorm WatchSPCAcadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 10 more6 hr
Apr 25, 9:35 AM CDTMesoscale DiscussionSPCAcadia, Ascension, Assumption, Avoyelles, Cameron, East Baton Rouge and 27 more115 min
Apr 25, 10:41 AM CDTSevere Thunderstorm WatchSPCAscension, Assumption, East Baton Rouge, East Feliciana, Iberville, Jefferson and 16 more7 hr
Apr 25, 1:50 PM CDTMesoscale DiscussionSPCOrleans, Saint Bernard, Saint Charles, Saint John the Baptist, Saint Tammany, Washington85 min
Apr 25, 12:50 AM CDTTornado WatchSPCAttala, Calhoun, Carroll, Chickasaw, Choctaw, Claiborne and 25 more6 hr
Apr 25, 4:12 AM CDTMesoscale DiscussionSPCClarke, George, Greene, Wayne63 min
Apr 24, 10:55 PM CDTMesoscale DiscussionSPCCameron65 min
Apr 25, 2:48 AM CDTMesoscale DiscussionSPCAtascosa, Bandera, Bexar, Caldwell, Comal, DeWitt and 17 more87 min
Apr 25, 3:09 AM CDTSevere Thunderstorm WatchSPCAtascosa, Austin, Bandera, Bastrop, Bexar, Blanco and 31 more7 hr
Apr 25, 4:31 AM CDTMesoscale DiscussionSPCAtascosa, Austin, Bandera, Bastrop, Bexar, Caldwell and 23 more89 min
Apr 25, 6:52 AM CDTMesoscale DiscussionSPCAtascosa, Brazoria, Chambers, DeWitt, Fort Bend, Frio and 11 more83 min

Nearby

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