Alert archive / Louisiana / Severe Thunderstorm Watches in 2016

Severe Thunderstorm Watch 129

April 30, 201628 parishes in Louisiana; 7 counties in Texas

The Storm Prediction Center issued this severe thunderstorm watch at Apr 30, 2016, 5:11 AM CDT for 28 parishes in Louisiana; 7 counties in Texas. It was in force for 9 hr.

The area

The outline as issued.

The facts

Issued
Apr 30, 2016, 5:11 AM CDT (10:11 UTC)
Expired
Apr 30, 2016, 2:00 PM CDT
In force
9 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt
All 35 counties

Acadia Parish, LA, Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Bienville Parish, LA, Calcasieu Parish, LA, Caldwell Parish, LA, Cameron Parish, LA, De Soto Parish, LA, Evangeline Parish, LA, Grant Parish, LA, Iberia Parish, LA, Jackson Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Rapides Parish, LA, Red River Parish, LA, Sabine Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, Winn Parish, LA, Hardin County, TX, Jasper County, TX, Jefferson County, TX, Newton County, TX, Orange County, TX, Sabine County, TX, Tyler County, TX

The radar

The Ft Polk radar (KPOE), 36 km from the middle of the area, began a volume at 10:12 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
30%
One or more gusts of 65 knots or more
10%
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
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 30, 5:31 AM CDTSevere Thunderstorm WarningSHVBienville, De Soto, Red River46 min
Apr 30, 6:08 AM CDTSevere Thunderstorm WarningLCHHardin, Jasper, Newton, Tyler37 min
Apr 30, 6:10 AM CDTTornado WarningLCHJasper, Newton35 min
Apr 30, 6:44 AM CDTSevere Thunderstorm WarningLCHBeauregard, Calcasieu, Vernon61 min
Apr 30, 7:03 AM CDTFlash Flood WarningLCHHardin, Tyler3 hr
Apr 30, 8:03 AM CDTTornado WarningSHVBienville, Jackson, Natchitoches, Red River, Winn27 min
Apr 30, 8:09 AM CDTTornado WarningSHVJackson, Lincoln, Union25 min
Apr 30, 8:26 AM CDTTornado WarningLCHAllen, Beauregard34 min
Apr 30, 8:43 AM CDTFlash Flood WarningLCHCalcasieu3 hr
Apr 30, 8:58 AM CDTFlash Flood WarningLCHJasper, Newton92 min
Apr 30, 9:55 AM CDTFlash Flood WarningLCHHardin, Jasper, Newton, Tyler5 hr
Apr 30, 10:08 AM CDTSevere Thunderstorm WarningLCHAcadia, Cameron, Lafayette, Saint Landry, Vermilion67 min
Apr 30, 10:50 AM CDTSevere Thunderstorm WarningLCHRapides55 min
Apr 30, 11:06 AM CDTSevere Thunderstorm WarningLCHAvoyelles, Saint Landry54 min
Apr 30, 11:17 AM CDTTornado WarningLCHAvoyelles, Saint Landry28 min
Apr 30, 11:42 AM CDTTornado Warning Tornado observedLCHAvoyelles, Saint Landry18 min
Apr 30, 12:12 PM CDTSevere Thunderstorm WarningLCHIberia, Saint Martin, St. Mary78 min
Apr 30, 12:27 PM CDTTornado WarningLCHIberia, Saint Martin, St. Mary44 min
Apr 30, 1:29 PM CDTSevere Thunderstorm WarningLCHIberia, Saint Martin, St. Mary36 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, 10.2 hours before the alert went out and 129 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 2016-04-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 835 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 2016-04-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 455 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
835 J/kg
Mixed-layer CIN
-28 J/kg
Mixed-layer LCL
591 m above ground
0-6 km bulk shear
68 kt
0-1 km storm-relative helicity
455 m²/s²
0-3 km storm-relative helicity
577 m²/s²
Significant tornado parameter
2.9
Supercell composite
11.8

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 29, 8:56 PM CDTMesoscale DiscussionSPCBienville, Bossier, Caddo, Claiborne, De Soto, Jackson and 8 more94 min
Apr 29, 9:58 PM CDTSevere Thunderstorm WatchSPCBienville, Bossier, Caddo, Claiborne, De Soto, Jackson and 8 more7 hr
Apr 29, 11:42 PM CDTMesoscale DiscussionSPCBienville, Bossier, Caddo, Claiborne, De Soto, Jackson and 5 more93 min
Apr 30, 3:23 AM CDTMesoscale DiscussionSPCBeauregard, Bienville, Bossier, Claiborne, De Soto, Lincoln and 5 more97 min
Apr 30, 7:38 AM CDTMesoscale DiscussionSPCAcadia, Allen, Beauregard, Calcasieu, Cameron, Evangeline and 2 more67 min
Apr 30, 10:22 AM CDTMesoscale DiscussionSPCAcadia, Ascension, Assumption, Calcasieu, Cameron, East Baton Rouge and 16 more53 min
Apr 30, 11:38 AM CDTSevere Thunderstorm WatchSPCAscension, Assumption, East Baton Rouge, East Feliciana, Iberville, Jefferson and 16 more7 hr
Apr 30, 1:35 PM CDTMesoscale DiscussionSPCAscension, Assumption, East Baton Rouge, East Feliciana, Iberia, Iberville and 22 more55 min
Apr 30, 4:00 PM CDTMesoscale DiscussionSPCAscension, Assumption, Jefferson, Lafourche, Livingston, Orleans and 10 more2 hr
Apr 29, 8:07 PM CDTMesoscale DiscussionSPCBandera, Bastrop, Bell, Bexar, Blanco, Bosque and 29 more83 min
Apr 29, 8:20 PM CDTSevere Thunderstorm WatchSPCBandera, Bastrop, Bexar, Blanco, Burnet, Caldwell and 19 more9 hr
Apr 30, 1:46 AM CDTMesoscale DiscussionSPCBandera, Bexar, Blanco, Comal, Hays, Kendall and 3 more59 min
Apr 30, 5:12 AM CDTMesoscale DiscussionSPCAustin, Burleson, Colorado, Fayette, Grimes, Harris and 7 more93 min
Apr 30, 5:27 AM CDTSevere Thunderstorm WatchSPCAustin, Brazoria, Brazos, Burleson, Chambers, Colorado and 11 more6 hr

Nearby

Severe Thunderstorm Watches in Louisiana, 2016Severe Thunderstorm Watches in Texas, 2016Every severe thunderstorm watch in 2016

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.