Alert archive / Texas / Flash Flood Warnings in 2021

Flash Flood Warning 53, NWS Austin/San Antonio, TX

September 29, 2021Bexar County, Comal County, Guadalupe County, Texas

NWS Austin/San Antonio, TX issued this flash flood warning at Sep 29, 2021, 1:23 AM CDT for Bexar County, Comal County, Guadalupe County, Texas. It was in force for 4 hr. 1 report 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
Sep 29, 2021, 1:23 AM CDT (06:23 UTC)
Expired
Sep 29, 2021, 5:00 AM CDT
In force
4 hr
Issued by
NWS Austin/San Antonio, TX
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

Counties Bexar County, TX, Comal County, TX, Guadalupe County, TX

The radar

The Austin/San Antonio radar (KEWX), 20 km from the middle of the area, began a volume at 06:24 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
Sep 29, 2:30 AM CDTFLASH FLOOD3 Sse Cibolo, TXTHE SCHERTZ EMERGENCY MANAGER INDICATED THAT A FEW ROADS WERE CLOSED DUE TO HIGH WATER INCLUDING LOWER SEGUIN ROAD AT WEIR ROAD AND 1518 AT OAK STREET.

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 00:00Z, 6.4 hours before the alert went out and 256 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 2021-09-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1438 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 00:00Z on 2021-09-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -3 square meters per square second.193958Sfc1 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
1438 J/kg
Mixed-layer CIN
-118 J/kg
Mixed-layer LCL
1769 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
-3 m²/s²
0-3 km storm-relative helicity
45 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

436 
WGUS54 KEWX 290623
FFWEWX
TXC029-091-187-291000-
/O.NEW.KEWX.FF.W.0053.210929T0623Z-210929T1000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Austin/San Antonio TX
123 AM CDT Wed Sep 29 2021

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

* Flash Flood Warning for...
  East Central Bexar County in south central Texas...
  Southeastern Comal County in south central Texas...
  West Central Guadalupe County in south central Texas...

* Until 500 AM CDT.

* At 123 AM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 4 inches of rain 
  have fallen. Additional rainfall amounts up 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, New Braunfels, Schertz, Seguin, Cibolo, Universal 
  City, Live Oak, Selma, Randolph AFB, Windcrest, Garden Ridge, 
  McQueeney, Marion, Santa Clara, Converse and Solms.

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.

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

&&

LAT...LON 2951 9820 2948 9829 2946 9837 2954 9837
      2958 9830 2960 9830 2969 9829 2973 9825
      2974 9824 2972 9819 2969 9808 2969 9807
      2966 9800 2961 9798 2953 9814

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

$$

MO
1 follow-up statement
367 
WGUS74 KEWX 290717
FFSEWX

Flash Flood Statement
National Weather Service Austin/San Antonio TX
217 AM CDT Wed Sep 29 2021

TXC029-091-187-291000-
/O.CON.KEWX.FF.W.0053.000000T0000Z-210929T1000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bexar TX-Comal TX-Guadalupe TX-
217 AM CDT Wed Sep 29 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 5 AM CDT EARLY THIS 
MORNING FOR EAST CENTRAL BEXAR, SOUTHEASTERN COMAL AND WEST CENTRAL 
GUADALUPE COUNTIES...

At 217 AM CDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 2 and 4 inches of rain have 
fallen. Additional rainfall amounts up to 1 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, New Braunfels, Schertz, Seguin, Cibolo, Universal 
  City, Live Oak, Selma, Randolph AFB, Windcrest, Garden Ridge, 
  McQueeney, Marion, Santa Clara, Converse and Solms.

Radar estimates suggest that between 3 and 4 and 1/2 inches of rain 
fell since 1130 pm over Highway 78 from Cibolo to McQueeny

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.

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

&&

LAT...LON 2951 9820 2948 9829 2946 9837 2954 9837
      2958 9830 2960 9830 2969 9829 2973 9825
      2974 9824 2972 9819 2969 9808 2969 9807
      2966 9800 2961 9798 2953 9814

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

$$

MO

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 28, 7:01 PM CDTSpecial Weather StatementEWXGonzales44 min
Sep 28, 7:34 PM CDTSpecial Weather StatementEWXMason26 min
Sep 28, 7:45 PM CDTSevere Thunderstorm WarningEWXWilliamson37 min
Sep 28, 7:57 PM CDTSpecial Weather StatementEWXTravis48 min
Sep 28, 8:43 PM CDTAreal Flood AdvisoryEWXTravis, Williamson3 hr
Sep 28, 8:44 PM CDTAreal Flood AdvisoryEWXGillespie4 hr
Sep 28, 9:04 PM CDTAreal Flood AdvisoryEWXZavala3 hr
Sep 28, 9:10 PM CDTAreal Flood AdvisoryEWXWilliamson3 hr
Sep 28, 9:12 PM CDTSpecial Weather StatementEWXBexar48 min
Sep 28, 9:29 PM CDTSpecial Weather StatementEWXBandera46 min
Sep 28, 9:40 PM CDTSpecial Weather StatementEWXHays50 min
Sep 28, 9:47 PM CDTAreal Flood AdvisoryEWXLee, Travis, Williamson3 hr
Sep 28, 9:52 PM CDTAreal Flood AdvisoryEWXBexar3 hr
Sep 28, 9:58 PM CDTAreal Flood AdvisoryEWXComal, Hays, Kendall, Travis3 hr
Sep 28, 10:10 PM CDTSpecial Weather StatementEWXKendall50 min
Sep 28, 10:13 PM CDTAreal Flood AdvisoryEWXBandera3 hr
Sep 28, 10:20 PM CDTSpecial Weather StatementEWXKendall40 min
Sep 28, 10:40 PM CDTSpecial Weather StatementEWXKerr50 min
Sep 28, 11:09 PM CDTSpecial Weather StatementEWXComal51 min
Sep 28, 11:19 PM CDTSpecial Weather StatementEWXComal, Guadalupe41 min
Sep 28, 11:23 PM CDTFlash Flood Warning Considerable damage threatEWXComal, Hays3 hr
Sep 28, 11:36 PM CDTAreal Flood AdvisoryEWXBastrop, Caldwell, Comal, Guadalupe, Hays, Travis3 hr
Sep 28, 11:49 PM CDTFlash Flood Warning Considerable damage threatEWXCaldwell, Comal, Guadalupe, Hays5 hr
Sep 29, 12:27 AM CDTSpecial Weather StatementEWXGonzales48 min
Sep 29, 12:37 AM CDTAreal Flood AdvisoryEWXBastrop, Caldwell, Fayette, Gonzales, Guadalupe, Lee3 hr
Sep 29, 12:43 AM CDTAreal Flood AdvisoryEWXBexar, Comal, Gonzales, Guadalupe3 hr
Sep 29, 1:34 AM CDTAreal Flood AdvisoryEWXGillespie3 hr
Sep 29, 2:05 AM CDTAreal Flood AdvisoryEWXDeWitt, Fayette, Gonzales, Karnes, Lavaca, Wilson4 hr
Sep 29, 2:28 AM CDTSpecial Weather StatementEWXBlanco47 min
Sep 29, 3:00 AM CDTSpecial Weather StatementEWXKerr45 min
Sep 29, 3:21 AM CDTSevere Thunderstorm WarningEWXGillespie, Kerr, Real42 min
Sep 29, 3:44 AM CDTSpecial Weather StatementEWXBandera46 min
Sep 29, 4:15 AM CDTAreal Flood AdvisoryEWXBandera, Kendall, Kerr4 hr
Sep 29, 6:25 AM CDTAreal Flood AdvisoryEWXBandera, Bexar, Medina3 hr

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.