Alert archive / Louisiana / Tornado Watches in 2017

Tornado Watch 98

March 29, 201713 parishes in Louisiana; 12 counties in Texas

The Storm Prediction Center issued this tornado watch at Mar 29, 2017, 2:11 PM CDT for 13 parishes in Louisiana; 12 counties in Texas. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Mar 29, 2017, 2:11 PM CDT (19:11 UTC)
Expired
Mar 29, 2017, 9:00 PM CDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 25 counties

Allen Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Caldwell Parish, LA, Cameron Parish, LA, Grant Parish, LA, Jefferson Davis Parish, LA, LaSalle Parish, LA, Natchitoches Parish, LA, Rapides Parish, LA, Sabine Parish, LA, Vernon Parish, LA, Winn Parish, LA, Angelina County, TX, Chambers County, TX, Galveston County, TX, Hardin County, TX, Jasper County, TX, Jefferson County, TX, Liberty County, TX, Newton County, TX, Orange County, TX, Sabine County, TX, San Augustine County, TX, Tyler County, TX

The radar

The Lake Charles radar (KLCH), 94 km from the middle of the area, began a volume at 19:12 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
40%
One or more EF2 to EF5 tornadoes
20%
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
30%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Mar 29, 2:17 PM CDTFlash Flood WarningHGXGalveston, Harris3 hr
Mar 29, 2:26 PM CDTSevere Thunderstorm WarningHGXLiberty, Polk34 min
Mar 29, 2:37 PM CDTSevere Thunderstorm WarningHGXChambers, Galveston, Harris, Liberty38 min
Mar 29, 2:44 PM CDTSevere Thunderstorm WarningLCHJasper, Tyler46 min
Mar 29, 2:46 PM CDTSevere Thunderstorm WarningLCHCalcasieu, Cameron41 min
Mar 29, 3:06 PM CDTTornado WarningHGXChambers, Harris24 min
Mar 29, 3:12 PM CDTFlash Flood WarningHGXChambers, Harris3 hr
Mar 29, 3:19 PM CDTTornado WarningLCHJasper, Tyler41 min
Mar 29, 3:20 PM CDTSevere Thunderstorm WarningLCHBeauregard, Calcasieu32 min
Mar 29, 3:26 PM CDTTornado WarningHGXChambers, Liberty34 min
Mar 29, 3:50 PM CDTSevere Thunderstorm WarningLCHHardin, Jefferson, Orange55 min
Mar 29, 3:54 PM CDTTornado WarningLCHJasper, Newton, Tyler51 min
Mar 29, 4:28 PM CDTFlash Flood WarningHGXChambers, Liberty3 hr
Mar 29, 4:30 PM CDTTornado WarningLCHJasper, Newton45 min
Mar 29, 4:54 PM CDTTornado WarningSHVSabine66 min
Mar 29, 5:00 PM CDTSevere Thunderstorm WarningLCHJefferson, Orange45 min
Mar 29, 5:14 PM CDTSevere Thunderstorm WarningSHVNatchitoches, Sabine61 min
Mar 29, 5:23 PM CDTTornado WarningSHVNatchitoches, Sabine52 min
Mar 29, 5:43 PM CDTSevere Thunderstorm WarningLCHCalcasieu, Cameron32 min
Mar 29, 5:51 PM CDTSevere Thunderstorm WarningSHVNatchitoches, Sabine54 min
Mar 29, 5:58 PM CDTSevere Thunderstorm WarningSHVGrant, LaSalle, Natchitoches, Winn62 min
Mar 29, 6:01 PM CDTTornado WarningLCHVernon29 min
Mar 29, 6:07 PM CDTSevere Thunderstorm WarningLCHCameron, Jefferson Davis53 min
Mar 29, 6:21 PM CDTSevere Thunderstorm WarningSHVGrant, Natchitoches, Sabine, Winn54 min
Mar 29, 6:37 PM CDTSevere Thunderstorm WarningLCHCalcasieu, Cameron23 min
Mar 29, 7:00 PM CDTSevere Thunderstorm WarningLCHAcadia, Calcasieu, Cameron, Jefferson Davis45 min
Mar 29, 7:53 PM CDTFlash Flood WarningLCHCalcasieu, Cameron, Jefferson Davis6 hr
Mar 29, 8:00 PM CDTTornado WarningLCHAcadia, Jefferson Davis30 min
Mar 29, 8:27 PM CDTTornado WarningLCHAllen, Evangeline, Rapides12 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, 7.2 hours before the alert went out and 96 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 2017-03-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 451 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 2017-03-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 162 square meters per square second.193958Sfc1 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
451 J/kg
Mixed-layer CIN
-384 J/kg
Mixed-layer LCL
879 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
162 m²/s²
0-3 km storm-relative helicity
229 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

008 
WWUS20 KWNS 291909
SEL8  
SPC WW 291909
LAZ000-TXZ000-CWZ000-300200-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 98
NWS Storm Prediction Center Norman OK
210 PM CDT Wed Mar 29 2017

The NWS Storm Prediction Center has issued a

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

* Effective this Wednesday afternoon and evening from 210 PM
  until 900 PM CDT.

* Primary threats include...
  A couple tornadoes possible
  Isolated very large hail events to 2 inches in diameter possible
  Isolated damaging wind gusts to 70 mph possible

SUMMARY...The environment across the region continues to become
increasingly favorable for a severe risk including the possibility
of a couple of tornadoes. Storms should continue to gradually
increase and expand northeastward through the late afternoon and
evening hours.

The tornado watch area is approximately along and 60 statute miles
north and south of a line from 45 miles north northwest of Galveston
TX to 30 miles east southeast of Fort Polk LA. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU8).

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 inches. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 550. Mean
storm motion vector 24025.

...Guyer

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 29, 1:31 PM CDTMesoscale DiscussionSPCBeauregard, Calcasieu, Cameron2 hr
Mar 29, 5:50 PM CDTMesoscale DiscussionSPCAcadia, Allen, Avoyelles, Beauregard, Bienville, Calcasieu and 27 more115 min
Mar 28, 7:45 PM CDTMesoscale DiscussionSPCArmstrong, Briscoe, Carson, Castro, Crosby, Deaf Smith and 9 more60 min
Mar 28, 9:07 PM CDTMesoscale DiscussionSPCBandera, Bexar, Blanco, Brown, Burnet, Callahan and 37 more23 min
Mar 28, 9:28 PM CDTSevere Thunderstorm WatchSPCAtascosa, Bandera, Bell, Bexar, Blanco, Bosque and 78 more8 hr
Mar 28, 10:21 PM CDTSevere Thunderstorm WatchSPCArcher, Baylor, Clay, Wichita, Wilbarger7 hr
Mar 28, 10:25 PM CDTMesoscale DiscussionSPCArcher, Clay, Cooke, Montague, Wichita65 min
Mar 28, 11:58 PM CDTMesoscale DiscussionSPCAnderson, Bastrop, Bell, Bexar, Blanco, Bosque and 29 more92 min
Mar 29, 2:54 AM CDTMesoscale DiscussionSPCCollin, Delta, Fannin, Franklin, Grayson, Hopkins and 7 more96 min
Mar 29, 8:23 AM CDTMesoscale DiscussionSPCBrazoria, Calhoun, Chambers, Fort Bend, Galveston, Hardin and 12 more67 min
Mar 29, 4:17 PM CDTTornado WatchSPCBowie, Cass, Morris8 hr

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.