Alert archive / Texas / Flash Flood Warnings in 2021

Flash Flood Warning 50, NWS Austin/San Antonio, TX

September 6, 2021Blanco County, Texas

NWS Austin/San Antonio, TX issued this flash flood warning at Sep 6, 2021, 6:19 PM CDT for Blanco 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
Sep 6, 2021, 6:19 PM CDT (23:19 UTC)
Expired
Sep 6, 2021, 9:30 PM CDT
In force
3 hr
Issued by
NWS Austin/San Antonio, TX
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County Blanco County, TX

The radar

The Austin/San Antonio radar (KEWX), 72 km from the middle of the area, began a volume at 23:22 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, 11.3 hours before the alert went out and 253 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 2021-09-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 103 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 2021-09-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -47 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
103 J/kg
Mixed-layer CIN
-269 J/kg
Mixed-layer LCL
1941 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
-47 m²/s²
0-3 km storm-relative helicity
-47 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.2

Open this sounding in Storm Lab

The text

As transmitted.

535 
WGUS54 KEWX 062319
FFWEWX
TXC031-070230-
/O.NEW.KEWX.FF.W.0050.210906T2319Z-210907T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Austin/San Antonio TX
619 PM CDT Mon Sep 6 2021

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

* Flash Flood Warning for...
  West Central Blanco County in south central Texas...

* Until 930 PM CDT.

* At 619 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 3 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...
  Johnson City.

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 3032 9846 3031 9839 3024 9839 3017 9837
      3015 9841 3026 9851

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

$$

MO
1 follow-up statement
271 
WGUS74 KEWX 062355
FFSEWX

Flash Flood Statement
National Weather Service Austin/San Antonio TX
655 PM CDT Mon Sep 6 2021

TXC031-070230-
/O.CON.KEWX.FF.W.0050.000000T0000Z-210907T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Blanco TX-
655 PM CDT Mon Sep 6 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 930 PM CDT THIS 
EVENING FOR WEST CENTRAL BLANCO COUNTY...

At 655 PM CDT, Doppler radar indicated the heavy rains have 
decreased into a light rain across the warned area around Johnson 
City and areas just to the west. Between 3 and 4 inches of rain have 
fallen. Flash flooding is likely occurring near Highway 290 near 
County Road 204 and over Flat Creek and Towhead Creek.

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...
  Johnson City.

A volunteer reporter observed 2.93 inches in a little over an hour 
about 2.2 miles north of Johnson City. Radar estimates based on this 
location would suggest that at least 4 inches of rain fell about 2 
to 4 miles west of Johnson City.

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 3032 9846 3031 9839 3024 9839 3017 9837
      3015 9841 3026 9851

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 5, 8:21 PM CDTAreal Flood AdvisoryEWXWilliamson2 hr
Sep 6, 2:32 PM CDTSpecial Weather StatementEWXGuadalupe28 min
Sep 6, 3:01 PM CDTSpecial Weather StatementEWXGuadalupe44 min
Sep 6, 3:03 PM CDTSpecial Weather StatementEWXBastrop42 min
Sep 6, 3:45 PM CDTSpecial Weather StatementEWXCaldwell, Fayette, Hays, Travis45 min
Sep 6, 3:47 PM CDTSpecial Weather StatementEWXBexar, Guadalupe43 min
Sep 6, 3:50 PM CDTSpecial Weather StatementEWXKendall55 min
Sep 6, 4:17 PM CDTSevere Thunderstorm WarningEWXCaldwell, Comal, Guadalupe, Hays58 min
Sep 6, 4:24 PM CDTSpecial Weather StatementEWXKendall51 min
Sep 6, 4:35 PM CDTSpecial Weather StatementEWXBandera, Edwards, Kinney, Medina, Real, Uvalde55 min
Sep 6, 4:39 PM CDTSpecial Weather StatementEWXBexar66 min
Sep 6, 4:51 PM CDTAreal Flood AdvisoryEWXBandera, Bexar, Comal, Kendall, Kerr, Medina3 hr
Sep 6, 5:02 PM CDTSpecial Weather StatementEWXHays58 min
Sep 6, 5:06 PM CDTSpecial Weather StatementEWXGonzales, Lavaca54 min
Sep 6, 5:19 PM CDTAreal Flood AdvisoryEWXBlanco, Comal, Hays, Kendall3 hr
Sep 6, 5:35 PM CDTSpecial Weather StatementEWXBlanco40 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.