Alert archive / Louisiana / Tornado Watches in 2017

Tornado Watch 190

May 3, 201730 parishes in Louisiana; 16 counties in Texas

The Storm Prediction Center issued this tornado watch at May 3, 2017, 7:32 AM CDT for 30 parishes in Louisiana; 16 counties in Texas. It was in force for 9 hr.

The area

The outline as issued.

The facts

Issued
May 3, 2017, 7:32 AM CDT (12:32 UTC)
Expired
May 3, 2017, 5:00 PM CDT
In force
9 hr
Issued by
the Storm Prediction Center
Largest hail expected
2.5 in
Strongest gust expected
60 kt
All 46 counties

Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, East Baton Rouge Parish, LA, Evangeline Parish, LA, Grant Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Lafourche Parish, LA, LaSalle Parish, LA, Natchitoches Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Sabine Parish, LA, Saint James Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Terrebonne Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Angelina County, TX, Chambers County, TX, Hardin County, TX, Jasper County, TX, Jefferson County, TX, Liberty County, TX, Nacogdoches County, TX, Newton County, TX, Orange County, TX, Polk County, TX, Sabine County, TX, San Augustine County, TX, San Jacinto County, TX, Shelby County, TX, Trinity County, TX, Tyler County, TX

The radar

The Lake Charles radar (KLCH), 50 km from the middle of the area, began a volume at 12:35 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
20%
Ten or more severe hail reports
40%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
90%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
May 3, 7:44 AM CDTTornado WarningLCHHardin, Jasper46 min
May 3, 7:48 AM CDTSevere Thunderstorm WarningLCHAcadia, Allen, Evangeline, Jefferson Davis57 min
May 3, 8:05 AM CDTSevere Thunderstorm WarningLCHIberia, Saint Martin40 min
May 3, 8:05 AM CDTSevere Thunderstorm WarningSHVSan Augustine26 min
May 3, 8:19 AM CDTSevere Thunderstorm WarningLIXAssumption, Lafourche, Saint James26 min
May 3, 8:25 AM CDTSevere Thunderstorm WarningLCHAllen, Evangeline65 min
May 3, 8:30 AM CDTTornado WarningLCHBeauregard45 min
May 3, 8:31 AM CDTSevere Thunderstorm WarningLCHCalcasieu, Cameron59 min
May 3, 8:33 AM CDTFlash Flood WarningLCHHardin, Jasper, Tyler3 hr
May 3, 8:37 AM CDTSevere Thunderstorm WarningLCHVermilion53 min
May 3, 8:42 AM CDTSevere Thunderstorm WarningSHVAngelina, Nacogdoches, Sabine, San Augustine17 min
May 3, 8:47 AM CDTTornado WarningLCHVermilion28 min
May 3, 8:50 AM CDTSevere Thunderstorm WarningLCHBeauregard, Vernon45 min
May 3, 8:55 AM CDTSevere Thunderstorm WarningLCHAllen, Avoyelles, Evangeline, Rapides37 min
May 3, 9:07 AM CDTFlash Flood WarningLCHJasper, Newton2 hr
May 3, 9:11 AM CDTTornado WarningLCHBeauregard, Calcasieu34 min
May 3, 9:12 AM CDTTornado WarningLCHVermilion63 min
May 3, 9:23 AM CDTFlash Flood WarningLCHAcadia, Calcasieu, Jefferson Davis, Vermilion112 min
May 3, 9:36 AM CDTSevere Thunderstorm WarningLIXTerrebonne25 min
May 3, 9:40 AM CDTSevere Thunderstorm WarningLIXJefferson, Lafourche, Plaquemines35 min
May 3, 9:55 AM CDTSevere Thunderstorm WarningLCHBeauregard, Calcasieu50 min
May 3, 10:03 AM CDTFlash Flood WarningLCHBeauregard, Calcasieu87 min
May 3, 10:27 AM CDTSevere Thunderstorm WarningLCHCalcasieu, Cameron, Jefferson Davis46 min
May 3, 10:28 AM CDTSevere Thunderstorm WarningLCHIberia, St. Mary47 min
May 3, 10:29 AM CDTSevere Thunderstorm WarningLCHIberia, St. Mary46 min
May 3, 10:48 AM CDTSevere Thunderstorm WarningLCHAcadia, Calcasieu, Cameron, Jefferson Davis57 min
May 3, 11:11 AM CDTSevere Thunderstorm WarningLCHAcadia, Cameron, Jefferson Davis, Lafayette, Saint Landry, Vermilion64 min
May 3, 11:14 AM CDTSevere Thunderstorm WarningLCHIberia, Saint Martin, St. Mary46 min
May 3, 11:16 AM CDTFlash Flood Warning EmergencyLCHCalcasieu, Jefferson Davis6 hr
May 3, 11:21 AM CDTFlash Flood WarningLCHAcadia, Iberia, Lafayette, Saint Martin, Vermilion6 hr
May 3, 11:26 AM CDTFlash Flood WarningLCHHardin, Jasper, Newton, Tyler6 hr
May 3, 11:35 AM CDTSevere Thunderstorm WarningLIXJefferson, Lafourche24 min
May 3, 11:39 AM CDTTornado WarningLCHSaint Martin, St. Mary36 min
May 3, 11:59 AM CDTSevere Thunderstorm WarningLCHIberia, Lafayette, Saint Martin, Vermilion61 min
May 3, 12:00 PM CDTSevere Thunderstorm WarningLCHSaint Martin, St. Mary29 min
May 3, 12:06 PM CDTTornado WarningLCHSaint Martin, St. Mary24 min
May 3, 12:25 PM CDTSevere Thunderstorm WarningLCHIberia, Saint Martin, St. Mary, Vermilion55 min
May 3, 12:28 PM CDTSevere Thunderstorm WarningLIXAssumption, Lafourche, Terrebonne47 min
May 3, 1:00 PM CDTFlash Flood WarningLCHBeauregard, Calcasieu5 hr
May 3, 1:14 PM CDTSevere Thunderstorm WarningLCHIberia, Saint Martin, St. Mary26 min
May 3, 1:47 PM CDTFlash Flood WarningLCHIberia, Saint Martin, St. Mary3 hr
May 3, 1:48 PM CDTSevere Thunderstorm WarningSHVAngelina, Nacogdoches, San Augustine42 min
May 3, 1:53 PM CDTSevere Thunderstorm WarningLIXJefferson, Lafourche, Terrebonne37 min
May 3, 1:59 PM CDTFlash Flood WarningLIXSaint James, Saint John the Baptist3 hr
May 3, 2:10 PM CDTSevere Thunderstorm WarningLIXJefferson, Lafourche, Saint Charles20 min
May 3, 2:14 PM CDTSevere Thunderstorm WarningSHVSabine21 min
May 3, 2:24 PM CDTSevere Thunderstorm WarningLIXJefferson, Lafourche, Orleans, Plaquemines, Saint Bernard, Saint Charles36 min
May 3, 2:35 PM CDTFlash Flood WarningLCHAcadia, Allen, Beauregard, Evangeline, Jefferson Davis, Lafayette and 1 more3 hr
May 3, 4:00 PM CDTSevere Thunderstorm WarningSHVCherokee, Nacogdoches, Rusk60 min
May 3, 4:08 PM CDTFlash Flood WarningLCHAllen, Beauregard, Rapides, Vernon6 hr
May 3, 4:23 PM CDTTornado WarningSHVPanola, Shelby23 min
May 3, 4:35 PM CDTSevere Thunderstorm WarningSHVNacogdoches, Panola, Rusk, Shelby55 min
May 3, 4:42 PM CDTSevere Thunderstorm WarningSHVBossier, Caddo, De Soto, Natchitoches, Red River63 min
May 3, 4:45 PM CDTFlash Flood WarningSHVAngelina, Cherokee, Nacogdoches, Rusk, San Augustine, Shelby3 hr
May 3, 4:55 PM CDTSevere Thunderstorm WarningHGXHouston, Trinity50 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

Lake Charles Mun, LA (KLCH), launched 12:00Z, 0.5 hours before the alert went out and 51 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, Lake Charles Mun, LA at 12:00Z on 2017-05-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2161 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, Lake Charles Mun, LA at 12:00Z on 2017-05-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 154 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
2161 J/kg
Mixed-layer CIN
-30 J/kg
Mixed-layer LCL
549 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
154 m²/s²
0-3 km storm-relative helicity
197 m²/s²
Significant tornado parameter
2.2
Supercell composite
12.3

Open this sounding in Storm Lab

The text

As transmitted.

735 
WWUS20 KWNS 031229
SEL0  
SPC WW 031229
LAZ000-TXZ000-CWZ000-032200-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 190
NWS Storm Prediction Center Norman OK
730 AM CDT Wed May 3 2017

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Southern and Western Louisiana
  Southeast Texas
  Coastal Waters

* Effective this Wednesday morning and afternoon from 730 AM
  until 500 PM CDT.

* Primary threats include...
  A few tornadoes possible
  Scattered large hail and isolated very large hail events to 2.5
    inches in diameter possible
  Scattered damaging wind gusts to 70 mph possible

SUMMARY...Severe thunderstorms will continue to develop and spread
east-northeastward today. Strengthening low-level/deep-layer shear
and an increasingly moist air mass near an inland-developing warm
front will support supercells capable of large hail and a few
tornadoes. Over time, one or more clusters may evolve and move
eastward with a damaging wind risk especially across southern
Louisiana.

The tornado watch area is approximately along and 70 statute miles
north and south of a line from 40 miles south southwest of Lufkin TX
to 50 miles south southeast of Baton Rouge LA. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU0).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and severe thunderstorms in and close to the watch
area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements
and possible warnings.

&&

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 2.5 inches. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 600. Mean
storm motion vector 24030.

...Guyer

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 3, 7:04 AM CDTMesoscale DiscussionSPCAcadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 13 more86 min
May 3, 10:07 AM CDTMesoscale DiscussionSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 21 more83 min
May 3, 12:34 PM CDTSevere Thunderstorm WatchSPCBossier, Caddo5 hr
May 3, 1:58 PM CDTMesoscale DiscussionSPCAcadia, Allen, Assumption, Beauregard, Calcasieu, Cameron and 11 more62 min
May 3, 3:48 PM CDTMesoscale DiscussionSPCAcadia, Allen, Beauregard, Calcasieu, Cameron, Jefferson Davis87 min
May 3, 3:59 PM CDTMesoscale DiscussionSPCBossier, Caddo91 min
May 3, 5:00 PM CDTSevere Thunderstorm WatchSPCAcadia, Allen, Beauregard, Bienville, Calcasieu, Cameron and 10 more7 hr
May 3, 6:54 PM CDTMesoscale DiscussionSPCAscension, Assumption, East Baton Rouge, Iberville, Livingston, Saint James and 3 more96 min
May 3, 1:30 AM CDTMesoscale DiscussionSPCCollingsworth, Donley, Gray, Hemphill, Wheeler2 hr
May 3, 7:48 AM CDTMesoscale DiscussionSPCBowie, Camp, Cass, Delta, Fannin, Franklin and 11 more117 min
May 3, 11:23 AM CDTMesoscale DiscussionSPCCoryell, Dallas, Ellis, Falls, Freestone, Henderson and 9 more2 hr
May 3, 1:48 PM CDTMesoscale DiscussionSPCAnderson, Bowie, Camp, Cass, Cherokee, Coryell and 31 more87 min

Nearby

Tornado Watches in Louisiana, 2017Tornado Watches in Texas, 2017Every tornado watch in 2017

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.