Alert archive / Texas / Severe Thunderstorm Watches in 2021

Severe Thunderstorm Watch 135

May 3, 202115 counties in Texas

The Storm Prediction Center issued this severe thunderstorm watch at May 3, 2021, 7:01 PM CDT for 15 counties in Texas. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
May 3, 2021, 7:01 PM CDT (00:01 UTC)
Expired
May 3, 2021, 11:00 PM CDT
In force
4 hr
Issued by
the Storm Prediction Center
Largest hail expected
3 in
Strongest gust expected
60 kt

Counties Atascosa County, TX, Bandera County, TX, Bexar County, TX, Blanco County, TX, Burnet County, TX, Comal County, TX, Frio County, TX, Gillespie County, TX, Guadalupe County, TX, Hays County, TX, Kendall County, TX, Kerr County, TX, Llano County, TX, Medina County, TX, Wilson County, TX

The radar

The Austin/San Antonio radar (KEWX), 60 km from the middle of the area, began a volume at 00:05 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
20%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
40%
One or more hailstones of 2 inches or more
40%
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
May 3, 7:12 PM CDTSevere Thunderstorm WarningEWXBexar, Comal, Medina63 min
May 3, 7:14 PM CDTSevere Thunderstorm WarningEWXBandera, Bexar, Blanco, Gillespie, Kendall, Kerr and 1 more61 min
May 3, 7:49 PM CDTSevere Thunderstorm WarningEWXBexar, Comal, Guadalupe56 min
May 3, 8:12 PM CDTSevere Thunderstorm WarningEWXBlanco, Burnet, Gillespie, Kendall, Llano48 min
May 3, 8:23 PM CDTSevere Thunderstorm WarningEWXBexar, Guadalupe, Wilson22 min
May 3, 8:43 PM CDTSevere Thunderstorm WarningEWXBexar, Gonzales, Guadalupe, Wilson62 min
May 3, 8:58 PM CDTSevere Thunderstorm WarningEWXBlanco, Burnet, Llano, Travis, Williamson62 min
May 3, 9:16 PM CDTSevere Thunderstorm WarningEWXBurnet, Llano, Travis, Williamson41 min
May 3, 10:08 PM CDTSevere Thunderstorm WarningEWXBurnet, Llano30 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, 0.0 hours before the alert went out and 232 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 2021-05-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2021-05-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -50 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
4428 m above ground
0-6 km bulk shear
53 kt
0-1 km storm-relative helicity
-50 m²/s²
0-3 km storm-relative helicity
13 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

562 
WWUS20 KWNS 032356
SEL5  
SPC WW 032356
TXZ000-040400-

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 135
NWS Storm Prediction Center Norman OK
700 PM CDT Mon May 3 2021

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  Part of the Texas Hill Country

* Effective this Monday evening from 700 PM until 1100 PM CDT.

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

SUMMARY...Isolated splitting supercells will be possible through
late evening, with the potential for very large hail and damaging
winds.

The severe thunderstorm watch area is approximately along and 25
statute miles east and west of a line from 95 miles north of San
Antonio TX to 65 miles south southwest of San Antonio TX. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU5).

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.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 128...WW 130...WW
131...WW 132...WW 133...WW 134...

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 600. Mean storm motion vector
27010.

...Thompson

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 3, 7:38 PM CDTMesoscale DiscussionSPCBosque, Collin, Dallas, Denton, Ellis, Fannin and 6 more97 min
May 3, 8:30 PM CDTMesoscale DiscussionSPCBexar, Blanco, Comal, Guadalupe, Hays, Kendall60 min
May 3, 8:38 PM CDTMesoscale DiscussionSPCBowie, Camp, Cass, Gregg, Marion, Morris and 4 more2 hr
May 3, 9:10 PM CDTMesoscale DiscussionSPCCallahan, Eastland, Fisher, Haskell, Jones, Nolan and 6 more95 min
May 3, 9:10 PM CDTSevere Thunderstorm WatchSPCBowie, Camp, Cass, Cherokee, Franklin, Gregg and 10 more7 hr
May 3, 9:52 PM CDTMesoscale DiscussionSPCAnderson, Bell, Coryell, Ellis, Falls, Freestone and 12 more53 min
May 3, 10:22 PM CDTSevere Thunderstorm WatchSPCAnderson, Bell, Collin, Cooke, Dallas, Delta and 28 more5 hr
May 3, 11:34 PM CDTMesoscale DiscussionSPCBowie, Camp, Cass, Falls, Franklin, Freestone and 12 more86 min
May 4, 6:44 AM CDTMesoscale DiscussionSPCAnderson, Bell, Brazos, Burleson, Camp, Cass and 23 more2 hr
May 4, 8:11 AM CDTSevere Thunderstorm WatchSPCAngelina, Austin, Brazos, Burleson, Chambers, Colorado and 22 more8 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.