Alert archive / Texas / Flash Flood Warnings in 2021

Flash Flood Warning 41, NWS Austin/San Antonio, TX

August 1, 2021Bexar County, Kendall County, Texas

NWS Austin/San Antonio, TX issued this flash flood warning at Aug 1, 2021, 6:56 PM CDT for Bexar County, Kendall County, Texas. It was in force for 3 hr. 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, 6:56 PM CDT (23:56 UTC)
Expired
Aug 1, 2021, 10:00 PM CDT
In force
3 hr
Issued by
NWS Austin/San Antonio, TX
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

Counties Bexar County, TX, Kendall County, TX

The radar

The Austin/San Antonio radar (KEWX), 61 km from the middle of the area, began a volume at 23:59 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, 11.9 hours before the alert went out and 215 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.

699 
WGUS54 KEWX 012356
FFWEWX
TXC029-259-020300-
/O.NEW.KEWX.FF.W.0041.210801T2356Z-210802T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Austin/San Antonio TX
656 PM CDT Sun Aug 1 2021

The National Weather Service in Austin/San Antonio has issued a

* Flash Flood Warning for...
  Northwestern Bexar County in south central Texas...
  South Central Kendall County in south central Texas...

* Until 1000 PM CDT.

* At 656 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Up to 3 inches of rain have 
  fallen. Additional rainfall amounts up to 3 inches are possible in 
  the warned area. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Life threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Radar.

  IMPACT...Life threatening flash flooding of creeks and streams,
           urban areas, highways, streets and underpasses.

* Some locations that will experience flash flooding include...
  San Antonio, Boerne, Fair Oaks Ranch, Cross Mountain, Leon 
  Springs, The Dominion, Scenic Oaks and Cascade Caverns.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 2974 9881 2978 9876 2978 9870 2980 9867
      2980 9865 2978 9861 2974 9864 2974 9861
      2974 9860 2975 9860 2974 9858 2975 9857
      2973 9855 2970 9855 2964 9862 2963 9866
      2968 9874 2972 9878

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

CP
1 follow-up statement
668 
WGUS74 KEWX 020121
FFSEWX

Flash Flood Statement
National Weather Service Austin/San Antonio TX
821 PM CDT Sun Aug 1 2021

TXC029-259-020300-
/O.CON.KEWX.FF.W.0041.000000T0000Z-210802T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bexar TX-Kendall TX-
821 PM CDT Sun Aug 1 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 10 PM CDT THIS 
EVENING FOR NORTHWESTERN BEXAR AND SOUTH CENTRAL KENDALL COUNTIES...

At 821 PM CDT, Doppler radar indicated light to moderate rain across 
the warned area. Up to 3 inches of rain have fallen. Additional 
rainfall amounts up to 1/2 inch are possible in the warned area. 
Flash flooding is ongoing or expected to begin shortly.

HAZARD...Life threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, highways, streets and underpasses.

Some locations that will experience flash flooding include...
  San Antonio, Boerne, Fair Oaks Ranch, Cross Mountain, Leon 
  Springs, The Dominion, Scenic Oaks and Cascade Caverns.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 2974 9881 2978 9876 2978 9870 2980 9867
      2980 9865 2978 9861 2974 9864 2974 9861
      2974 9860 2975 9860 2974 9858 2975 9857
      2973 9855 2970 9855 2964 9862 2963 9866
      2968 9874 2972 9878

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

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, 5:47 PM CDTSevere Thunderstorm WarningEWXBexar, Comal33 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

Nearby

Flash Flood Warnings in Texas, 2021Every flash flood 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.