Alert archive / Texas / Flash Flood Warnings in 2021

Flash Flood Warning 42, NWS Austin/San Antonio, TX

August 2, 2021Comal County, Guadalupe County, Texas

NWS Austin/San Antonio, TX issued this flash flood warning at Aug 2, 2021, 4:09 AM CDT for 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
Aug 2, 2021, 4:09 AM CDT (09:09 UTC)
Expired
Aug 2, 2021, 8:30 AM CDT
In force
4 hr
Issued by
NWS Austin/San Antonio, TX
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

Counties Comal County, TX, Guadalupe County, TX

The radar

The Austin/San Antonio radar (KEWX), 1 km from the middle of the area, began a volume at 09:11 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
Aug 2, 7:00 AM CDTHEAVY RAIN 4.731 N Geronimo, TX24 HOUR RAINFALL.

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

The nearest sounding before it

Corpus Christi, TX (KCRP), launched 00:00Z, 9.2 hours before the alert went out and 229 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 00:00Z on 2021-08-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1117 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 00:00Z on 2021-08-02The 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
1117 J/kg
Mixed-layer CIN
-99 J/kg
Mixed-layer LCL
1455 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
18 m²/s²
0-3 km storm-relative helicity
84 m²/s²
Significant tornado parameter
0.0
Supercell composite
-1.6

Open this sounding in Storm Lab

The text

As transmitted.

132 
WGUS54 KEWX 020909
FFWEWX
TXC091-187-021330-
/O.NEW.KEWX.FF.W.0042.210802T0909Z-210802T1330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Austin/San Antonio TX
409 AM CDT Mon Aug 2 2021

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

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

* Until 830 AM CDT.

* At 409 AM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area which covers New Braunfels, 
  Zorn, Geronimo, and Clear Springs. Between 2 and 4 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...
  New Braunfels, Seguin, McQueeney, Kingsbury, Geronimo, Zorn, New 
  Braunfels Regional Airport, Freiheit, Gruene 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.

&&

LAT...LON 2966 9819 2975 9814 2974 9803 2979 9794
      2976 9786 2966 9786 2959 9797

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
Aug 1, 7:53 PM CDTAreal Flood AdvisoryEWXBandera, Real3 hr
Aug 1, 11:02 PM CDTAreal Flood AdvisoryEWXKendall3 hr
Aug 2, 12:27 AM CDTAreal Flood AdvisoryEWXBastrop, Hays, Travis3 hr
Aug 2, 3:45 AM CDTAreal Flood AdvisoryEWXComal, Guadalupe, Hays4 hr
Aug 2, 3:53 AM CDTAreal Flood AdvisoryEWXEdwards, Kinney4 hr
Aug 2, 4:13 AM CDTAreal Flood AdvisoryEWXUvalde4 hr
Aug 2, 5:41 AM CDTFlash Flood Warning Considerable damage threatEWXGuadalupe4 hr
Aug 2, 5:45 AM CDTAreal Flood AdvisoryEWXBexar, Guadalupe, Wilson3 hr
Aug 2, 5:51 AM CDTAreal Flood AdvisoryEWXBandera, Real3 hr
Aug 2, 5:57 AM CDTAreal Flood AdvisoryEWXComal, Hays4 hr
Aug 2, 6:37 AM CDTAreal Flood AdvisoryEWXBandera, Kerr, Medina4 hr
Aug 2, 6:37 AM CDTFlash Flood Warning Considerable damage threatEWXComal5 hr
Aug 2, 6:52 AM CDTFlash Flood Warning Considerable damage threatEWXHays3 hr
Aug 2, 7:15 AM CDTAreal Flood AdvisoryEWXBandera, Bexar, Comal, Kendall, Kerr, Medina5 hr
Aug 2, 7:29 AM CDTSpecial Weather StatementEWXBexar46 min
Aug 2, 7:47 AM CDTFlash Flood Warning Considerable damage threatEWXBexar, Comal, Kendall4 hr
Aug 2, 8:13 AM CDTAreal Flood AdvisoryEWXKinney3 hr
Aug 2, 8:15 AM CDTAreal Flood AdvisoryEWXBastrop, Lee, Travis, Williamson5 hr
Aug 2, 8:18 AM CDTSpecial Weather StatementEWXBexar, Comal42 min
Aug 2, 8:26 AM CDTAreal Flood AdvisoryEWXBexar, Comal, Kendall4 hr
Aug 2, 8:36 AM CDTAreal Flood AdvisoryEWXBexar4 hr
Aug 2, 9:16 AM CDTAreal Flood AdvisoryEWXBlanco, Hays, Travis3 hr
Aug 2, 10:25 AM CDTAreal Flood AdvisoryEWXKinney, Maverick, Uvalde, Zavala3 hr
Aug 2, 2:45 PM CDTAreal Flood AdvisoryEWXBandera, Edwards, Kerr, Real, Val Verde3 hr
Aug 2, 4:56 PM CDTAreal Flood AdvisoryEWXTravis, Williamson3 hr
Aug 2, 5:12 PM CDTAreal Flood AdvisoryEWXBlanco, Hays3 hr
Aug 2, 6:19 PM CDTAreal Flood AdvisoryEWXCaldwell, Hays, Travis2 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.