Alert archive / Texas / Flash Flood Warnings in 2021

Flash Flood Warning 52, NWS Austin/San Antonio, TX

September 28, 20214 counties in Texas

NWS Austin/San Antonio, TX issued this flash flood warning at Sep 28, 2021, 11:49 PM CDT for 4 counties in Texas. It was in force for 5 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 28, 2021, 11:49 PM CDT (04:49 UTC)
Expired: Sep 29, 2021, 5:00 AM CDT
In force: 5 hr
Issued by: NWS Austin/San Antonio, TX
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Caldwell County, TX, Comal County, TX, Guadalupe County, TX, Hays County, TX

The radar

The Austin/San Antonio radar (KEWX), 12 km from the middle of the area, began a volume at 04:50 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

Time	Report	Where	Remark
Sep 29, 3:00 AM CDT	FLASH FLOOD	4 S San Marcos, TX	A LOW WATER CROSSING STREAM GAUGE AT OLD BASTROP HIGHWAY AND COTTONWOOD CREEK SHOWED WATER OVER THE ROAD.

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, 4.8 hours before the alert went out and 277 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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.

798 
WGUS54 KEWX 290449
FFWEWX
TXC055-091-187-209-290800-
/O.NEW.KEWX.FF.W.0052.210929T0449Z-210929T0800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Austin/San Antonio TX
1149 PM CDT Tue Sep 28 2021

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

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

* Until 300 AM CDT.

* At 1149 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 4 inches of rain 
  have fallen from Canyon Lake and New Braunfels to San Marcos and 
  Kyle. 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...
  New Braunfels, San Marcos, Kyle, Seguin, Canyon Lake, Martindale, 
  Uhland, Staples, Zorn, Geronimo, Hunter, Redwood, New Braunfels 
  Regional Airport, Freiheit, Gruene, San Marcos Regional Airport, 
  Reedville and Maxwell.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 2980 9830 2982 9826 2983 9813 2985 9808
      2994 9796 2999 9787 2999 9785 2995 9781
      2989 9777 2981 9779 2973 9783 2968 9787
      2967 9792 2966 9800 2969 9807 2972 9819
      2977 9832

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

$$

CP

2 follow-up statements

321 
WGUS74 KEWX 290615
FFSEWX

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

TXC055-091-187-209-290800-
/O.CON.KEWX.FF.W.0052.000000T0000Z-210929T0800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Caldwell TX-Comal TX-Guadalupe TX-Hays TX-
115 AM CDT Wed Sep 29 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 3 AM CDT EARLY THIS 
MORNING FOR WEST CENTRAL CALDWELL, EAST CENTRAL COMAL, NORTH CENTRAL 
GUADALUPE AND SOUTHEASTERN HAYS COUNTIES...

At 115 AM CDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 3 and 5 inches of rain have 
fallen over much of Comal and Hayes Counties. Another round of 
storms near New Braunfels at 112 AM will move over southeast parts 
of the warned area and produce additional rainfall amounts up to 2 
inches over Zorn and Staples. Flash flooding is ongoing over Comal 
and Hayes counties and may begin shortly over parts of Guadalupe and 
Calwell counties.

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, San Marcos, Kyle, Seguin, Canyon Lake, Martindale, 
  Uhland, Staples, Zorn, Geronimo, Hunter, Redwood, New Braunfels 
  Regional Airport, Freiheit, Gruene, San Marcos Regional Airport, 
  Reedville and Maxwell.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 2980 9830 2982 9826 2983 9813 2985 9808
      2994 9796 2999 9787 2999 9785 2995 9781
      2989 9777 2981 9779 2973 9783 2968 9787
      2967 9792 2966 9800 2969 9807 2972 9819
      2977 9832

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

$$

MO

459 
WGUS54 KEWX 290751
FFWEWX
TXC055-091-187-209-291000-
/O.EXT.KEWX.FF.W.0052.000000T0000Z-210929T1000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

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

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

* Until 500 AM CDT.

* At 251 AM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 3 and 6 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...
  New Braunfels, San Marcos, Kyle, Seguin, Canyon Lake, Martindale, 
  Uhland, Staples, Zorn, Geronimo, Hunter, Redwood, New Braunfels 
  Regional Airport, Freiheit, Gruene, San Marcos Regional Airport, 
  Reedville and Maxwell.

One more round of heavy rainfall will move over the warned area, 
especially from New Braunfels to Staples with another inch of rain 
will fall after this part of the warned area already received 2 to 4 
inches. This will extend the threat of flash flooding through 5 AM 
CDT.

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 2980 9830 2982 9826 2983 9813 2985 9808
      2994 9796 2999 9787 2999 9785 2995 9781
      2989 9777 2981 9779 2973 9783 2968 9787
      2967 9792 2966 9800 2969 9807 2972 9819
      2977 9832

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.

Issued	Product	Office	Counties	Lasted
Sep 28, 7:01 PM CDT	Special Weather Statement	EWX	Gonzales	44 min
Sep 28, 7:34 PM CDT	Special Weather Statement	EWX	Mason	26 min
Sep 28, 7:45 PM CDT	Severe Thunderstorm Warning	EWX	Williamson	37 min
Sep 28, 7:57 PM CDT	Special Weather Statement	EWX	Travis	48 min
Sep 28, 8:43 PM CDT	Areal Flood Advisory	EWX	Travis, Williamson	3 hr
Sep 28, 8:44 PM CDT	Areal Flood Advisory	EWX	Gillespie	4 hr
Sep 28, 9:04 PM CDT	Areal Flood Advisory	EWX	Zavala	3 hr
Sep 28, 9:10 PM CDT	Areal Flood Advisory	EWX	Williamson	3 hr
Sep 28, 9:12 PM CDT	Special Weather Statement	EWX	Bexar	48 min
Sep 28, 9:29 PM CDT	Special Weather Statement	EWX	Bandera	46 min
Sep 28, 9:40 PM CDT	Special Weather Statement	EWX	Hays	50 min
Sep 28, 9:47 PM CDT	Areal Flood Advisory	EWX	Lee, Travis, Williamson	3 hr
Sep 28, 9:52 PM CDT	Areal Flood Advisory	EWX	Bexar	3 hr
Sep 28, 9:58 PM CDT	Areal Flood Advisory	EWX	Comal, Hays, Kendall, Travis	3 hr
Sep 28, 10:10 PM CDT	Special Weather Statement	EWX	Kendall	50 min
Sep 28, 10:13 PM CDT	Areal Flood Advisory	EWX	Bandera	3 hr
Sep 28, 10:20 PM CDT	Special Weather Statement	EWX	Kendall	40 min
Sep 28, 10:40 PM CDT	Special Weather Statement	EWX	Kerr	50 min
Sep 28, 11:09 PM CDT	Special Weather Statement	EWX	Comal	51 min
Sep 28, 11:19 PM CDT	Special Weather Statement	EWX	Comal, Guadalupe	41 min
Sep 28, 11:23 PM CDT	Flash Flood Warning Considerable damage threat	EWX	Comal, Hays	3 hr
Sep 28, 11:36 PM CDT	Areal Flood Advisory	EWX	Bastrop, Caldwell, Comal, Guadalupe, Hays, Travis	3 hr
Sep 29, 12:27 AM CDT	Special Weather Statement	EWX	Gonzales	48 min
Sep 29, 12:37 AM CDT	Areal Flood Advisory	EWX	Bastrop, Caldwell, Fayette, Gonzales, Guadalupe, Lee	3 hr
Sep 29, 12:43 AM CDT	Areal Flood Advisory	EWX	Bexar, Comal, Gonzales, Guadalupe	3 hr
Sep 29, 1:23 AM CDT	Flash Flood Warning Considerable damage threat	EWX	Bexar, Comal, Guadalupe	4 hr
Sep 29, 1:34 AM CDT	Areal Flood Advisory	EWX	Gillespie	3 hr
Sep 29, 2:05 AM CDT	Areal Flood Advisory	EWX	DeWitt, Fayette, Gonzales, Karnes, Lavaca, Wilson	4 hr
Sep 29, 2:28 AM CDT	Special Weather Statement	EWX	Blanco	47 min
Sep 29, 3:00 AM CDT	Special Weather Statement	EWX	Kerr	45 min
Sep 29, 3:21 AM CDT	Severe Thunderstorm Warning	EWX	Gillespie, Kerr, Real	42 min
Sep 29, 3:44 AM CDT	Special Weather Statement	EWX	Bandera	46 min
Sep 29, 4:15 AM CDT	Areal Flood Advisory	EWX	Bandera, Kendall, Kerr	4 hr
Sep 29, 6:25 AM CDT	Areal Flood Advisory	EWX	Bandera, Bexar, Medina	3 hr

Nearby

Flash Flood Warnings in Texas, 2021 Every 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.