Alert archive / Texas / Severe Thunderstorm Watches in 2016

Severe Thunderstorm Watch 270

June 18, 201617 parishes in Louisiana; 25 counties in Texas

The Storm Prediction Center issued this severe thunderstorm watch at Jun 18, 2016, 1:16 PM CDT for 17 parishes in Louisiana; 25 counties in Texas. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Jun 18, 2016, 1:16 PM CDT (18:16 UTC)
Expired
Jun 18, 2016, 6:53 PM CDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 42 counties

Acadia Parish, LA, Allen Parish, LA, Beauregard Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, De Soto Parish, LA, Evangeline Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Natchitoches Parish, LA, Rapides Parish, LA, Red River Parish, LA, Sabine Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, Angelina County, TX, Cherokee County, TX, Gregg County, TX, Hardin County, TX, Harrison County, TX, Houston County, TX, Jasper County, TX, Jefferson County, TX, Liberty County, TX, Marion County, TX, Nacogdoches County, TX, Newton County, TX, Orange County, TX, Panola County, TX, Polk County, TX, Rusk County, TX, Sabine County, TX, San Augustine County, TX, San Jacinto County, TX, Shelby County, TX, Smith County, TX, Trinity County, TX, Tyler County, TX, Upshur County, TX, Wood County, TX

The radar

The Shreveport radar (KSHV), 121 km from the middle of the area, began a volume at 18:16 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
10%
One or more EF2 to EF5 tornadoes
2%
Ten or more severe wind reports
50%
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

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

IssuedProductOfficeCountiesLasted
Jun 18, 1:28 PM CDTSevere Thunderstorm WarningLCHVernon62 min
Jun 18, 1:42 PM CDTSevere Thunderstorm WarningSHVBossier, Caddo, De Soto63 min
Jun 18, 1:45 PM CDTSevere Thunderstorm WarningLCHAllen, Beauregard, Evangeline, Rapides, Vernon60 min
Jun 18, 2:39 PM CDTSevere Thunderstorm WarningLCHBeauregard, Vernon66 min
Jun 18, 2:46 PM CDTSevere Thunderstorm WarningLCHAcadia, Allen, Evangeline, Jefferson Davis59 min
Jun 18, 3:03 PM CDTSevere Thunderstorm WarningLCHJasper, Newton42 min
Jun 18, 3:13 PM CDTSevere Thunderstorm WarningSHVAngelina, Nacogdoches, Sabine, San Augustine, Shelby62 min
Jun 18, 4:00 PM CDTSevere Thunderstorm WarningSHVCass, Harrison, Marion45 min
Jun 18, 6:21 PM CDTSevere Thunderstorm WarningHGXChambers, Galveston, Harris, Liberty, Montgomery54 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, 6.3 hours before the alert went out and 127 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 12:00Z on 2016-06-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2685 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 12:00Z on 2016-06-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 41 square meters per square second.1939Sfc1 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
2685 J/kg
Mixed-layer CIN
-17 J/kg
Mixed-layer LCL
906 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
41 m²/s²
0-3 km storm-relative helicity
63 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.1

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 18, 11:31 AM CDTMesoscale DiscussionSPCAcadia, Allen, Beauregard, Calcasieu, Cameron, De Soto and 11 more89 min
Jun 18, 3:20 PM CDTMesoscale DiscussionSPCBeauregard, Calcasieu, Cameron, Jefferson Davis25 min
Jun 18, 3:14 PM CDTMesoscale DiscussionSPCArcher, Baylor, Clay, Foard, Hardeman, Montague and 2 more2 hr

Nearby

Severe Thunderstorm Watches in Texas, 2016Severe Thunderstorm Watches in Louisiana, 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.