Alert archive / Texas / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 177, NWS Austin/San Antonio, TX

August 1, 2021Bexar County, Comal County, Texas

NWS Austin/San Antonio, TX issued this severe thunderstorm warning at Aug 1, 2021, 5:47 PM CDT for Bexar County, Comal County, Texas. It was in force for 33 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 1, 2021, 5:47 PM CDT (22:47 UTC)
Expired
Aug 1, 2021, 6:20 PM CDT
In force
33 min
Issued by
NWS Austin/San Antonio, TX
Area
Storm-based polygon
Hail
1.5 in
Wind
50.0 mph

Counties Bexar County, TX, Comal County, TX

The radar

The Austin/San Antonio radar (KEWX), 35 km from the middle of the area, began a volume at 22:51 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.

The nearest sounding before it

Del Rio, TX (KDRT), launched 12:00Z, 10.8 hours before the alert went out and 247 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 2021-08-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1723 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Del Rio, TX at 12:00Z on 2021-08-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 18 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
1723 J/kg
Mixed-layer CIN
-128 J/kg
Mixed-layer LCL
1127 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
18 m²/s²
0-3 km storm-relative helicity
29 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

654 
WUUS54 KEWX 012247
SVREWX
TXC029-091-012345-
/O.NEW.KEWX.SV.W.0177.210801T2247Z-210801T2345Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Austin/San Antonio TX
547 PM CDT Sun Aug 1 2021

The National Weather Service in Austin San Antonio has issued a

* Severe Thunderstorm Warning for...
  North central Bexar County in south central Texas...
  Central Comal County in south central Texas...

* Until 645 PM CDT.

* At 547 PM CDT, a severe thunderstorm was located over Spring
  Branch, or 10 miles west of Canyon Lake Dam, moving south at 5 mph.

  HAZARD...Ping pong ball size hail.

  SOURCE...Radar indicated.

  IMPACT...People and animals outdoors will be injured. Expect 
           damage to roofs, siding, windows, and vehicles.

* Locations impacted include...
  Canyon Lake Dam, Canyon Lake, Bulverde, Spring Branch, Smithson
  Valley, Fischer, Guadalupe River State Park, Timberwood Park,
  Anhalt, Honey Creek State Natural Area, Startzville and Specht
  Store.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Large hail, damaging winds, and continuous cloud to ground lightning
are occurring with this storm. Move indoors immediately. Lightning is
one of nature's leading killers. Remember, if you can hear thunder,
you are close enough to be struck by lightning.

If on or near Canyon Lake, get away from the water and move indoors 
or inside a vehicle. Remember, lightning can strike out to 15 miles 
from the parent thunderstorm. If you can hear thunder, you are close 
enough to be struck by lightning. Move to safe shelter now!  Do not 
be caught on the water in a thunderstorm.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 2998 9825 2975 9814 2968 9844 2977 9858
      2994 9841
TIME...MOT...LOC 2247Z 359DEG 5KT 2990 9837 

HAIL...1.50IN
WIND...<50MPH
 
$$

CP
1 follow-up statement
717 
WWUS54 KEWX 012320
SVSEWX

Severe Weather Statement
National Weather Service Austin/San Antonio TX
620 PM CDT Sun Aug 1 2021

TXC029-091-012330-
/O.CAN.KEWX.SV.W.0177.000000T0000Z-210801T2345Z/
Bexar TX-Comal TX-
620 PM CDT Sun Aug 1 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTH CENTRAL BEXAR AND
CENTRAL COMAL COUNTIES IS CANCELLED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been cancelled.  However heavy rain is
still possible with this thunderstorm.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Austin San Antonio.

LAT...LON 2998 9825 2975 9814 2968 9844 2977 9858
      2994 9841
TIME...MOT...LOC 2320Z 359DEG 5KT 2970 9879 

$$

CP

The office that day

Everything else NWS Austin/San Antonio, TX issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 1, 2:29 PM CDTSpecial Weather StatementEWXEdwards46 min
Aug 1, 3:16 PM CDTSpecial Weather StatementEWXKinney, Real44 min
Aug 1, 5:09 PM CDTAreal Flood AdvisoryEWXHays, Travis, Williamson3 hr
Aug 1, 5:11 PM CDTAreal Flood AdvisoryEWXVal Verde3 hr
Aug 1, 5:36 PM CDTSpecial Weather StatementEWXComal39 min
Aug 1, 6:01 PM CDTSpecial Weather StatementEWXBexar59 min
Aug 1, 6:14 PM CDTAreal Flood AdvisoryEWXBandera, Bexar, Comal, Kendall, Medina3 hr
Aug 1, 6:43 PM CDTSpecial Weather StatementEWXBexar47 min
Aug 1, 6:56 PM CDTFlash Flood Warning Considerable damage threatEWXBexar, Kendall3 hr

Nearby

Severe Thunderstorm Warnings in Texas, 2021Every severe thunderstorm warning 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.