Alert archive / Texas / Flash Flood Warnings in 2021

Flash Flood Warning 40, NWS Austin/San Antonio, TX

July 9, 2021Atascosa County, Bexar County, Texas

NWS Austin/San Antonio, TX issued this flash flood warning at Jul 9, 2021, 4:25 PM CDT for Atascosa County, Bexar 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
Jul 9, 2021, 4:25 PM CDT (21:25 UTC)
Expired
Jul 9, 2021, 7:30 PM CDT
In force
3 hr
Issued by
NWS Austin/San Antonio, TX
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

Counties Atascosa County, TX, Bexar County, TX

The radar

The Austin/San Antonio radar (KEWX), 82 km from the middle of the area, began a volume at 21:29 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

Corpus Christi, TX (KCRP), launched 12:00Z, 9.4 hours before the alert went out and 198 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, Corpus Christi, TX at 12:00Z on 2021-07-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 994 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, Corpus Christi, TX at 12:00Z on 2021-07-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -14 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
994 J/kg
Mixed-layer CIN
-19 J/kg
Mixed-layer LCL
646 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
-14 m²/s²
0-3 km storm-relative helicity
7 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

517 
WGUS54 KEWX 092125
FFWEWX
TXC013-029-100030-
/O.NEW.KEWX.FF.W.0040.210709T2125Z-210710T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Austin/San Antonio TX
425 PM CDT Fri Jul 9 2021

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

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

* Until 730 PM CDT.

* At 425 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 4 inches of rain 
  have fallen. Additional rainfall amounts up to 3 inches are 
  possible in the warned area as more bands of showers move into the 
  warned area from the south. 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, Poteet, Somerset, Leming, Sandy Oaks, Von Ormy, Buena 
  Vista, Thelma, Espey, Losoya, Mitchell Lake, Amphion and Braunig 
  Lake.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 2923 9866 2931 9866 2934 9864 2935 9860
      2929 9852 2928 9842 2924 9836 2920 9837
      2914 9847 2908 9850 2903 9855 2897 9855
      2895 9856 2894 9858 2894 9863 2896 9868
      2900 9868 2911 9866 2916 9866 2920 9867

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

$$

CP
1 follow-up statement
717 
WGUS74 KEWX 092308
FFSEWX

Flash Flood Statement
National Weather Service Austin/San Antonio TX
608 PM CDT Fri Jul 9 2021

TXC013-029-100030-
/O.CON.KEWX.FF.W.0040.000000T0000Z-210710T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Atascosa TX-Bexar TX-
608 PM CDT Fri Jul 9 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 730 PM CDT THIS 
EVENING FOR NORTHWESTERN ATASCOSA AND SOUTHWESTERN BEXAR COUNTIES...

At 608 PM CDT, Doppler radar indicated light to moderate rain across 
the warned area. Between 1 and 5 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. Rain 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, Poteet, Somerset, Leming, Sandy Oaks, Von Ormy, Buena 
  Vista, Thelma, Espey, Losoya, Mitchell Lake, Amphion and Braunig 
  Lake.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 2923 9866 2931 9866 2934 9864 2935 9860
      2929 9852 2928 9842 2924 9836 2920 9837
      2914 9847 2908 9850 2903 9855 2897 9855
      2895 9856 2894 9858 2894 9863 2896 9868
      2900 9868 2911 9866 2916 9866 2920 9867

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
Jul 8, 9:47 PM CDTAreal Flood AdvisoryEWXDeWitt, Karnes6 hr
Jul 8, 10:46 PM CDTAreal Flood AdvisoryEWXKarnes5 hr
Jul 8, 11:01 PM CDTFlash Flood Warning Considerable damage threatEWXKarnes5 hr
Jul 9, 3:10 AM CDTFlash Flood Warning Considerable damage threatEWXDeWitt, Karnes, Wilson3 hr
Jul 9, 4:14 AM CDTAreal Flood AdvisoryEWXKarnes4 hr
Jul 9, 11:17 AM CDTAreal Flood AdvisoryEWXDeWitt, Gonzales5 hr
Jul 9, 11:19 AM CDTAreal Flood AdvisoryEWXDeWitt, Lavaca5 hr
Jul 9, 2:10 PM CDTAreal Flood AdvisoryEWXBexar, Comal, Guadalupe, Wilson4 hr
Jul 9, 2:29 PM CDTAreal Flood AdvisoryEWXDimmit, Frio, Zavala3 hr
Jul 9, 3:26 PM CDTAreal Flood AdvisoryEWXAtascosa, Bexar3 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.