Alert archive / Texas / Severe Thunderstorm Watches in 2017

Severe Thunderstorm Watch 397

July 4, 201720 counties in Texas

The Storm Prediction Center issued this severe thunderstorm watch at Jul 4, 2017, 6:51 PM CDT for 20 counties in Texas. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Jul 4, 2017, 6:51 PM CDT (23:51 UTC)
Expired
Jul 5, 2017, 1:00 AM CDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt

Counties Bailey County, TX, Briscoe County, TX, Castro County, TX, Cochran County, TX, Crosby County, TX, Dickens County, TX, Floyd County, TX, Garza County, TX, Hale County, TX, Hall County, TX, Hockley County, TX, Kent County, TX, Lamb County, TX, Lubbock County, TX, Lynn County, TX, Motley County, TX, Parmer County, TX, Swisher County, TX, Terry County, TX, Yoakum County, TX

The radar

The Lubbock radar (KLBB), 45 km from the middle of the area, began a volume at 23:52 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
30%
One or more gusts of 65 knots or more
20%
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
60%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jul 4, 7:03 PM CDTSevere Thunderstorm WarningLUBKent42 min
Jul 4, 7:14 PM CDTSevere Thunderstorm WarningLUBCastro, Lamb, Parmer46 min
Jul 4, 7:48 PM CDTSevere Thunderstorm WarningLUBBailey, Castro, Hale, Lamb, Parmer, Swisher42 min
Jul 4, 8:31 PM CDTSevere Thunderstorm WarningLUBBailey, Castro, Cochran, Hale, Hockley, Lamb and 4 more29 min
Jul 4, 8:59 PM CDTSevere Thunderstorm WarningLUBBriscoe, Cochran, Crosby, Floyd, Hale, Hockley and 6 more46 min
Jul 4, 9:42 PM CDTSevere Thunderstorm WarningLUBCrosby, Garza, Hockley, Lubbock, Lynn, Terry and 1 more48 min
Jul 4, 9:46 PM CDTSevere Thunderstorm WarningLUBBriscoe, Crosby, Floyd, Hale, Hall, Motley and 1 more44 min
Jul 4, 10:28 PM CDTSevere Thunderstorm WarningLUBBriscoe, Hall32 min
Jul 4, 10:33 PM CDTSevere Thunderstorm WarningLUBCrosby, Dickens, Garza, Kent, Lynn42 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

Amarillo Airport, TX (KAMA), launched 12:00Z, 11.9 hours before the alert went out and 137 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, Amarillo Airport, TX at 12:00Z on 2017-07-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 52 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, Amarillo Airport, TX at 12:00Z on 2017-07-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 103 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
52 J/kg
Mixed-layer CIN
-472 J/kg
Mixed-layer LCL
2067 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
103 m²/s²
0-3 km storm-relative helicity
156 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 3, 7:26 PM CDTMesoscale DiscussionSPCArmstrong, Briscoe, Carson, Childress, Collingsworth, Cottle and 10 more64 min
Jul 3, 10:30 PM CDTMesoscale DiscussionSPCArcher, Clay, Cooke, Grayson, Jack, Montague and 2 more60 min
Jul 3, 10:50 PM CDTSevere Thunderstorm WatchSPCCollin, Cooke, Dallas, Delta, Denton, Fannin and 12 more5 hr
Jul 4, 12:51 AM CDTMesoscale DiscussionSPCBowie, Lamar, Red River114 min
Jul 4, 4:44 PM CDTMesoscale DiscussionSPCBailey, Castro, Deaf Smith, Oldham, Parmer2 hr

Nearby

Severe Thunderstorm Watches in Texas, 2017Every severe thunderstorm 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.