Alert archive / Texas / Flash Flood Warnings in 2021

Flash Flood Warning 2, NWS Austin/San Antonio, TX

April 30, 2021Bexar County, Texas

NWS Austin/San Antonio, TX issued this flash flood warning at Apr 30, 2021, 5:48 PM CDT for Bexar County, Texas. It was in force for 6 hr. 4 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Apr 30, 2021, 5:48 PM CDT (22:48 UTC)
Expired
Apr 30, 2021, 11:45 PM CDT
In force
6 hr
Issued by
NWS Austin/San Antonio, TX
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County Bexar County, TX

The radar

The Austin/San Antonio radar (KEWX), 47 km from the middle of the area, began a volume at 22:46 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 was reported inside it

TimeReportWhereRemark
Apr 30, 8:05 PM CDTFLASH FLOOD2 Se Castle Hills, TXMPING REPORT OF ROAD CLOSED DUE TO FLOODING AND/OR VEHICLES STRANDED.
Apr 30, 9:11 PM CDTFLASH FLOOD1 Sw San Antonio, TXMPING REPORT OF ROAD CLOSED DUE TO FLOODING AND/OR VEHICLES STRANDED.
Apr 30, 9:28 PM CDTFLASH FLOOD1 Ssw Olmos Park, TXFLOOD WATERS FORCING EVACUATIONS AT APARTMENT COMPLEX NEAR HOWARD ST AND SAN PEDRO AVE.
Apr 30, 9:33 PM CDTFLASH FLOODSan Antonio, TXEMERGENCY MANAGEMENT REPORTS SEVERAL WATER EVACUATIONS AND CLOSED ROADWAYS AROUND THE CITY.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Del Rio, TX (KDRT), launched 12:00Z, 10.8 hours before the alert went out and 228 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 2021-04-30Temperature 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°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Del Rio, TX at 12:00Z on 2021-04-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -26 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
867 m above ground
0-6 km bulk shear
69 kt
0-1 km storm-relative helicity
-26 m²/s²
0-3 km storm-relative helicity
106 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

672 
WGUS54 KEWX 302248
FFWEWX
TXC029-010145-
/O.NEW.KEWX.FF.W.0002.210430T2248Z-210501T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Austin/San Antonio TX
548 PM CDT Fri Apr 30 2021

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

* Flash Flood Warning for...
  Bexar County in south central Texas...

* Until 845 PM CDT.

* At 548 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 inches of rain 
  have fallen. Additional rainfall amounts of 1 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, Schertz, Universal City, Live Oak, Selma, San Antonio 
  Int Airport, Stinson Municipal Airport, Randolph AFB, Leon Valley, 
  Helotes, Fair Oaks Ranch, Kirby, Alamo Heights, Windcrest, Terrell 
  Hills, Bulverde, Shavano Park, Hollywood Park, Cross Mountain and 
  Olmos Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 2975 9865 2974 9864 2974 9861 2976 9855
      2974 9853 2974 9845 2972 9844 2973 9842
      2975 9842 2969 9838 2966 9838 2966 9835
      2962 9835 2960 9831 2956 9830 2953 9825
      2919 9861 2926 9880 2969 9881 2971 9879

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

$$

BRADY
3 follow-up statements
881 
WGUS74 KEWX 010018
FFSEWX

Flash Flood Statement
National Weather Service Austin/San Antonio TX
718 PM CDT Fri Apr 30 2021

TXC029-010145-
/O.CON.KEWX.FF.W.0002.000000T0000Z-210501T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bexar TX-
718 PM CDT Fri Apr 30 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 845 PM CDT THIS 
EVENING FOR BEXAR COUNTY...

At 718 PM CDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 1 and 2 inches of rain have 
fallen. Additional rainfall amounts of 1 to 2 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, Schertz, Universal City, Live Oak, Selma, San Antonio 
  Int Airport, Stinson Municipal Airport, Randolph AFB, Leon Valley, 
  Helotes, Fair Oaks Ranch, Kirby, Alamo Heights, Windcrest, Terrell 
  Hills, Bulverde, Shavano Park, Hollywood Park, Cross Mountain and 
  Olmos Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 2975 9865 2974 9864 2974 9861 2976 9855
      2974 9853 2974 9845 2972 9844 2973 9842
      2975 9842 2969 9838 2966 9838 2966 9835
      2962 9835 2960 9831 2956 9830 2953 9825
      2919 9861 2926 9880 2969 9881 2971 9879

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

$$

BRADY
705 
WGUS54 KEWX 010134
FFWEWX
TXC029-010315-
/O.EXT.KEWX.FF.W.0002.000000T0000Z-210501T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Austin/San Antonio TX
834 PM CDT Fri Apr 30 2021

The National Weather Service in Austin/San Antonio has extended the

* Flash Flood Warning for...
  Bexar County in south central Texas...

* Until 1015 PM CDT.

* At 834 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1.5 and 2.5 inches of 
  rain have fallen. Additional rainfall amounts of 1 to 2 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, Schertz, Universal City, Live Oak, Selma, San Antonio 
  Int Airport, Stinson Municipal Airport, Randolph AFB, Leon Valley, 
  Helotes, Fair Oaks Ranch, Kirby, Alamo Heights, Windcrest, Terrell 
  Hills, Bulverde, Shavano Park, Hollywood Park, Cross Mountain and 
  Olmos Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 2975 9865 2974 9864 2974 9861 2976 9855
      2974 9853 2974 9845 2972 9844 2973 9842
      2975 9842 2969 9838 2966 9838 2966 9835
      2962 9835 2960 9831 2956 9830 2953 9825
      2919 9861 2926 9880 2969 9881 2971 9879

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

$$

BRADY
069 
WGUS54 KEWX 010251
FFWEWX
TXC029-010445-
/O.EXT.KEWX.FF.W.0002.000000T0000Z-210501T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Austin/San Antonio TX
951 PM CDT Fri Apr 30 2021

The National Weather Service in Austin/San Antonio has extended the

* Flash Flood Warning for...
  Bexar County in south central Texas...

* Until 1145 PM CDT.

* At 951 PM CDT, emergency management reports several high water 
  rescues and numerous street closures across San Antonio and Bexar 
  county. Between 1.5 and 3 inches of rain have fallen. Additional 
  rainfall amounts up to 1 inch are possible in the warned area. 
  Flash flooding is already occurring.

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

  SOURCE...Emergency management reported.

  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, Schertz, Universal City, Live Oak, Selma, San Antonio 
  Int Airport, Stinson Municipal Airport, Randolph AFB, Leon Valley, 
  Helotes, Fair Oaks Ranch, Kirby, Alamo Heights, Windcrest, Terrell 
  Hills, Bulverde, Shavano Park, Hollywood Park, Cross Mountain and 
  Olmos Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 2975 9865 2974 9864 2974 9861 2976 9855
      2974 9853 2974 9845 2972 9844 2973 9842
      2975 9842 2969 9838 2966 9838 2966 9835
      2962 9835 2960 9831 2956 9830 2953 9825
      2919 9861 2926 9880 2969 9881 2971 9879

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

BRADY

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 30, 3:34 AM CDTFlash Flood WatchEWXAtascosa, Bandera, Bastrop, Bexar, Blanco, Caldwell and 15 more39 hr
Apr 30, 11:25 AM CDTAreal Flood AdvisoryEWXAtascosa3 hr
Apr 30, 4:53 PM CDTAreal Flood AdvisoryEWXBexar112 min
Apr 30, 6:52 PM CDTAreal Flood AdvisoryEWXComal69 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.