Alert archive / Texas / Severe Thunderstorm Watches in 2021

Severe Thunderstorm Watch 96

April 15, 202125 counties in Texas

The Storm Prediction Center issued this severe thunderstorm watch at Apr 15, 2021, 8:36 AM CDT for 25 counties in Texas. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued
Apr 15, 2021, 8:36 AM CDT (13:36 UTC)
Expired
Apr 15, 2021, 5:00 PM CDT
In force
8 hr
Issued by
the Storm Prediction Center
Largest hail expected
3 in
Strongest gust expected
60 kt
All 25 counties

Bandera County, TX, Blanco County, TX, Burnet County, TX, Concho County, TX, Crockett County, TX, Edwards County, TX, Gillespie County, TX, Irion County, TX, Kendall County, TX, Kerr County, TX, Kimble County, TX, Kinney County, TX, Llano County, TX, Mason County, TX, McCulloch County, TX, Medina County, TX, Menard County, TX, Real County, TX, San Saba County, TX, Schleicher County, TX, Sutton County, TX, Tom Green County, TX, Uvalde County, TX, Val Verde County, TX, Williamson County, TX

The radar

The San Angelo radar (KSJT), 138 km from the middle of the area, began a volume at 13:36 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
5%
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
70%
One or more hailstones of 2 inches or more
70%
Six or more combined severe hail and wind reports
90%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 15, 8:40 AM CDTSevere Thunderstorm WarningEWXKinney65 min
Apr 15, 9:01 AM CDTSevere Thunderstorm WarningSJTSchleicher, Sutton44 min
Apr 15, 9:04 AM CDTSevere Thunderstorm WarningEWXEdwards24 min
Apr 15, 9:32 AM CDTSevere Thunderstorm WarningEWXEdwards17 min
Apr 15, 9:34 AM CDTSevere Thunderstorm WarningSJTKimble, Sutton41 min
Apr 15, 9:42 AM CDTSevere Thunderstorm WarningEWXKinney, Uvalde63 min
Apr 15, 9:45 AM CDTSevere Thunderstorm WarningSJTKimble, Menard, Schleicher, Sutton45 min
Apr 15, 10:03 AM CDTSevere Thunderstorm WarningSJTKimble, Menard42 min
Apr 15, 10:27 AM CDTSevere Thunderstorm WarningSJTMcCulloch, Menard33 min
Apr 15, 10:34 AM CDTSevere Thunderstorm WarningSJTKimble41 min
Apr 15, 10:42 AM CDTSevere Thunderstorm WarningEWXUvalde45 min
Apr 15, 10:54 AM CDTSevere Thunderstorm WarningSJTMcCulloch, Mason, Menard51 min
Apr 15, 11:31 AM CDTSevere Thunderstorm WarningSJTBrown, McCulloch, San Saba44 min
Apr 15, 11:58 AM CDTSevere Thunderstorm WarningSJTBrown, McCulloch, San Saba47 min
Apr 15, 12:00 PM CDTSevere Thunderstorm WarningSJTMason45 min
Apr 15, 12:15 PM CDTSevere Thunderstorm WarningEWXGillespie, Llano60 min
Apr 15, 1:07 PM CDTSevere Thunderstorm WarningEWXBlanco, Burnet, Llano, Travis53 min
Apr 15, 1:52 PM CDTSevere Thunderstorm WarningEWXBurnet, Williamson36 min
Apr 15, 2:07 PM CDTSevere Thunderstorm WarningEWXBurnet, Williamson40 min
Apr 15, 2:18 PM CDTSevere Thunderstorm WarningSJTSan Saba16 min
Apr 15, 2:38 PM CDTSevere Thunderstorm WarningSJTSan Saba37 min
Apr 15, 2:57 PM CDTSevere Thunderstorm WarningEWXBurnet, Llano63 min
Apr 15, 3:21 PM CDTSevere Thunderstorm WarningEWXBurnet, Williamson54 min
Apr 15, 3:56 PM CDTSevere Thunderstorm WarningEWXTravis, Williamson49 min
Apr 15, 4:36 PM CDTSevere Thunderstorm WarningEWXBastrop, Lee, Travis, Williamson54 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 12:00Z, 1.6 hours before the alert went out and 165 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 12:00Z on 2021-04-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2593 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 12:00Z on 2021-04-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 169 square meters per square second.19395878Sfc1 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
2593 J/kg
Mixed-layer CIN
-44 J/kg
Mixed-layer LCL
634 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
169 m²/s²
0-3 km storm-relative helicity
338 m²/s²
Significant tornado parameter
4.6
Supercell composite
21.4

Open this sounding in Storm Lab

The text

As transmitted.

125 
WWUS20 KWNS 151333
SEL6  
SPC WW 151333
TXZ000-152000-

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 96
NWS Storm Prediction Center Norman OK
835 AM CDT Thu Apr 15 2021

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  The Edwards Plateau of central Texas

* Effective this Thursday morning and afternoon from 835 AM until
  300 PM CDT.

* Primary threats include...
  Scattered large hail and isolated very large hail events to 3
    inches in diameter likely
  Isolated damaging wind gusts to 70 mph possible

SUMMARY...Elevated supercells are expected through the morning and
potentially into the early afternoon across the Edwards Plateau and
parts of the Hill Country.  The storm environment will favor the
potential for isolated very large hail (baseball size or larger),
along with isolated damaging gusts.

The severe thunderstorm watch area is approximately along and 90
statute miles east and west of a line from 55 miles north northeast
of Junction TX to 25 miles southeast of Del Rio TX. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU6).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for 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. Severe thunderstorms can and occasionally do produce
tornadoes.

&&

AVIATION...A few severe thunderstorms with hail surface and aloft to
3 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 550. Mean storm motion vector
27020.

...Thompson

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 15, 8:17 AM CDTMesoscale DiscussionSPCAtascosa, Bandera, Bexar, Blanco, Comal, Edwards and 13 more2 hr
Apr 15, 10:56 AM CDTMesoscale DiscussionSPCBandera, Concho, Edwards, Gillespie, Kerr, Kimble and 9 more94 min
Apr 15, 12:24 PM CDTMesoscale DiscussionSPCBastrop, Bell, Blanco, Burnet, Coryell, Falls and 12 more2 hr
Apr 15, 4:55 PM CDTMesoscale DiscussionSPCAustin, Brazoria, Burleson, Fort Bend, Harris, Lee and 4 more3 hr

Nearby

Severe Thunderstorm Watches in Texas, 2021Every severe thunderstorm watch in 2021

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.