Alert archive / Texas / Tornado Watches in 2020

Tornado Watch 102

April 11, 202029 counties in Texas

The Storm Prediction Center issued this tornado watch at Apr 11, 2020, 8:37 PM CDT for 29 counties in Texas. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Apr 11, 2020, 8:37 PM CDT (01:37 UTC)
Expired
Apr 12, 2020, 1:59 AM CDT
In force
5 hr
Issued by
the Storm Prediction Center
Largest hail expected
3 in
Strongest gust expected
65 kt
All 29 counties

Atascosa County, TX, Bandera County, TX, Bastrop County, TX, Bexar County, TX, Blanco County, TX, Caldwell County, TX, Comal County, TX, DeWitt County, TX, Dimmit County, TX, Edwards County, TX, Fayette County, TX, Frio County, TX, Gillespie County, TX, Gonzales County, TX, Guadalupe County, TX, Hays County, TX, Karnes County, TX, Kendall County, TX, Kerr County, TX, Kinney County, TX, Lavaca County, TX, Lee County, TX, Maverick County, TX, Medina County, TX, Real County, TX, Travis County, TX, Uvalde County, TX, Wilson County, TX, Zavala County, TX

The radar

The Austin/San Antonio radar (KEWX), 107 km from the middle of the area, began a volume at 01:36 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
70%
One or more EF2 to EF5 tornadoes
50%
Ten or more severe wind reports
70%
One or more gusts of 65 knots or more
60%
Ten or more severe hail reports
80%
One or more hailstones of 2 inches or more
70%
Six or more combined severe hail and wind reports
95%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 11, 8:58 PM CDTTornado WarningEWXKinney, Uvalde32 min
Apr 11, 9:27 PM CDTSevere Thunderstorm WarningEWXKinney, Uvalde48 min
Apr 11, 10:11 PM CDTSevere Thunderstorm WarningEWXUvalde64 min
Apr 12, 12:53 AM CDTSevere Thunderstorm WarningEWXEdwards, Val Verde67 min
Apr 12, 1:53 AM CDTSevere Thunderstorm WarningEWXEdwards, Kerr, Real67 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

Del Rio, TX (KDRT), launched 00:00Z, 1.6 hours before the alert went out and 167 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 2020-04-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3028 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 2020-04-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 185 square meters per square second.1939587897117Sfc1 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
3028 J/kg
Mixed-layer CIN
-37 J/kg
Mixed-layer LCL
1174 m above ground
0-6 km bulk shear
80 kt
0-1 km storm-relative helicity
185 m²/s²
0-3 km storm-relative helicity
286 m²/s²
Significant tornado parameter
4.8
Supercell composite
23.5

Open this sounding in Storm Lab

The text

As transmitted.

054 
WWUS20 KWNS 120135
SEL2  
SPC WW 120135
TXZ000-120900-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 102
NWS Storm Prediction Center Norman OK
840 PM CDT Sat Apr 11 2020

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  South Central Texas

* Effective this Saturday night and Sunday morning from 840 PM
  until 400 AM CDT.

* Primary threats include...
  A few tornadoes likely with a couple intense tornadoes possible
  Widespread large hail and isolated very large hail events to 3
    inches in diameter likely
  Scattered damaging winds and isolated significant gusts to 75
    mph likely

SUMMARY...A few intense supercell thunderstorms are expected to
track eastward across the watch area through the late evening and
overnight hours.  Storms will be capable of very large hail and
tornadoes, along with locally damaging wind gusts.

The tornado watch area is approximately along and 45 statute miles
north and south of a line from 85 miles west of Hondo TX to 45 miles
north of Victoria TX. For a complete depiction of the watch see the
associated watch outline update (WOUS64 KWNS WOU2).

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.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 100...WW 101...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 3 inches. Extreme turbulence and surface wind
gusts to 65 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 27035.

...Hart

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 11, 7:51 PM CDTMesoscale DiscussionSPCEdwards, Kinney, Real, Sutton, Uvalde, Val Verde84 min
Apr 11, 9:23 PM CDTMesoscale DiscussionSPCArcher, Baylor, Callahan, Clay, Coke, Coleman and 23 more67 min
Apr 11, 11:03 PM CDTMesoscale DiscussionSPCAtascosa, Bandera, Bexar, Caldwell, Comal, DeWitt and 12 more57 min
Apr 12, 1:37 AM CDTMesoscale DiscussionSPCBandera, Bell, Blanco, Bosque, Brazos, Brown and 44 more113 min
Apr 12, 1:59 AM CDTTornado WatchSPCBandera, Bastrop, Bell, Bexar, Blanco, Bosque and 37 more6 hr
Apr 12, 4:15 AM CDTMesoscale DiscussionSPCBandera, Bastrop, Bell, Blanco, Bosque, Brown and 24 more90 min
Apr 12, 5:52 AM CDTTornado WatchSPCAnderson, Angelina, Brazos, Burleson, Cherokee, Freestone and 19 more8 hr
Apr 12, 7:18 AM CDTMesoscale DiscussionSPCAnderson, Camp, Cass, Cherokee, Falls, Freestone and 20 more87 min
Apr 12, 9:30 AM CDTMesoscale DiscussionSPCSan Augustine, Shelby90 min
Apr 12, 1:10 PM CDTMesoscale DiscussionSPCCamp, Collin, Cooke, Dallas, Delta, Denton and 17 more95 min
Apr 12, 2:51 PM CDTSevere Thunderstorm WatchSPCBowie, Camp, Cass, Delta, Fannin, Franklin and 11 more5 hr
Apr 12, 6:14 PM CDTMesoscale DiscussionSPCBowie, Camp, Cass, Franklin, Gregg, Harrison and 8 more91 min

Nearby

Tornado Watches in Texas, 2020Every tornado watch in 2020

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.