Alert archive / Texas / Tornado Watches in 2017

Tornado Watch 107

April 1, 201712 counties in Texas

The Storm Prediction Center issued this tornado watch at Apr 1, 2017, 10:28 PM CDT for 12 counties in Texas. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued
Apr 1, 2017, 10:28 PM CDT (03:28 UTC)
Expired
Apr 2, 2017, 6:00 AM CDT
In force
8 hr
Issued by
the Storm Prediction Center
Largest hail expected
4 in
Strongest gust expected
60 kt

Counties Bandera County, TX, Edwards County, TX, Gillespie County, TX, Kerr County, TX, Kimble County, TX, Kinney County, TX, Mason County, TX, Medina County, TX, Real County, TX, Sutton County, TX, Uvalde County, TX, Val Verde County, TX

The radar

The Laughlin AFB radar (KDFX), 73 km from the middle of the area, began a volume at 03:28 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
30%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
20%
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
60%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 1, 10:58 PM CDTSevere Thunderstorm WarningEWXVal Verde47 min
Apr 1, 11:43 PM CDTSevere Thunderstorm WarningEWXVal Verde47 min
Apr 2, 12:26 AM CDTSevere Thunderstorm WarningEWXVal Verde49 min
Apr 2, 12:30 AM CDTSevere Thunderstorm WarningSJTSutton45 min
Apr 2, 1:15 AM CDTSevere Thunderstorm WarningEWXVal Verde45 min
Apr 2, 1:32 AM CDTFlash Flood WarningEWXKinney, Val Verde6 hr
Apr 2, 2:29 AM CDTSevere Thunderstorm WarningEWXEdwards, Kinney, Val Verde32 min
Apr 2, 2:57 AM CDTSevere Thunderstorm WarningEWXEdwards, Kinney48 min
Apr 2, 3:12 AM CDTSevere Thunderstorm WarningEWXKinney, Val Verde48 min
Apr 2, 3:20 AM CDTTornado WarningEWXKinney25 min
Apr 2, 3:47 AM CDTTornado WarningEWXEdwards18 min
Apr 2, 3:54 AM CDTSevere Thunderstorm WarningEWXKinney51 min
Apr 2, 3:56 AM CDTTornado WarningEWXEdwards, Real34 min
Apr 2, 4:04 AM CDTSevere Thunderstorm WarningEWXEdwards, Real41 min
Apr 2, 4:08 AM CDTSevere Thunderstorm WarningEWXKinney, Maverick37 min
Apr 2, 4:14 AM CDTTornado WarningEWXEdwards17 min
Apr 2, 4:40 AM CDTFlash Flood WarningEWXEdwards, Kinney3 hr
Apr 2, 4:41 AM CDTSevere Thunderstorm WarningEWXEdwards, Kinney, Maverick49 min
Apr 2, 5:25 AM CDTSevere Thunderstorm WarningEWXKinney, Uvalde50 min
Apr 2, 5:54 AM CDTTornado WarningEWXBandera, Kerr, Real30 min
Apr 2, 5:57 AM CDTFlash Flood WarningEWXReal3 hr

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Del Rio, TX (KDLF), launched 00:00Z, 3.5 hours before the alert went out and 73 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, Del Rio, TX at 00:00Z on 2017-04-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 564 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, Del Rio, TX at 00:00Z on 2017-04-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 10 square meters per square second.1939587897Sfc1 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
564 J/kg
Mixed-layer CIN
-71 J/kg
Mixed-layer LCL
2447 m above ground
0-6 km bulk shear
54 kt
0-1 km storm-relative helicity
10 m²/s²
0-3 km storm-relative helicity
75 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.1

Open this sounding in Storm Lab

The text

As transmitted.

980 
WWUS20 KWNS 020326
SEL7  
SPC WW 020326
TXZ000-021100-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 107
NWS Storm Prediction Center Norman OK
1025 PM CDT Sat Apr 1 2017

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  South-central and southwest Texas

* Effective this Saturday night and Sunday morning from 1025 PM
  until 600 AM CDT.

* Primary threats include...
  A couple tornadoes possible
  Scattered large hail and isolated very large hail events to 4
    inches in diameter possible
  Isolated damaging wind gusts to 70 mph possible

SUMMARY...At first, a pair of thunderstorms moving out of Mexico
will pose a threat for large, damaging hail and severe gusts.  With
time, additional storm development is expected on either side of the
international border, moving into an environment increasingly
favorable for a tornado or two as well.  See SPC mesoscale
discussion 396 for initial meteorological reasoning.

The tornado watch area is approximately along and 45 statute miles
either side of a line from 20 miles west northwest of Del Rio TX to
45 miles east southeast of Junction TX. For a complete depiction of
the watch see the associated watch outline update (WOUS64 KWNS
WOU7).

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

...Edwards

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 1, 7:20 PM CDTMesoscale DiscussionSPCVal Verde85 min
Apr 1, 8:44 PM CDTMesoscale DiscussionSPCBrown, Callahan, Coleman, Comanche, Concho, Eastland and 5 more61 min
Apr 1, 10:06 PM CDTMesoscale DiscussionSPCBandera, Bexar, Blanco, Comal, Edwards, Gillespie and 9 more114 min
Apr 2, 2:53 AM CDTMesoscale DiscussionSPCBandera, Edwards, Gillespie, Kerr, Kimble, Kinney and 6 more82 min
Apr 2, 5:16 AM CDTMesoscale DiscussionSPCAnderson, Angelina, Bandera, Bastrop, Bell, Bexar and 51 more119 min
Apr 2, 6:00 AM CDTTornado WatchSPCAnderson, Atascosa, Bandera, Bastrop, Bell, Bexar and 51 more7 hr
Apr 2, 9:04 AM CDTMesoscale DiscussionSPCAngelina, Houston, Jasper, Montgomery, Nacogdoches, Newton and 8 more2 hr
Apr 2, 9:44 AM CDTMesoscale DiscussionSPCAustin, Bastrop, Brazos, Burleson, Caldwell, Cherokee and 19 more2 hr
Apr 2, 10:39 AM CDTTornado WatchSPCAngelina, Austin, Cherokee, Colorado, Gregg, Hardin and 20 more5 hr
Apr 2, 12:22 PM CDTMesoscale DiscussionSPCAngelina, Nacogdoches, Sabine, San Augustine, Shelby, Trinity83 min
Apr 2, 1:34 PM CDTTornado Watch PDSSPCAngelina, Hardin, Jasper, Nacogdoches, Newton, Orange and 4 more7 hr
Apr 2, 2:06 PM CDTMesoscale DiscussionSPCSabine54 min
Apr 2, 4:23 PM CDTMesoscale DiscussionSPCAransas, Brazoria, Calhoun, Cameron, Jackson, Kenedy and 5 more3 hr
Apr 2, 5:54 PM CDTMesoscale DiscussionSPCHardin, Jasper, Newton, Orange96 min

Nearby

Tornado 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.