Alert archive / Texas / Flash Flood Warnings in 2021

Flash Flood Warning 7, NWS Austin/San Antonio, TX

May 1, 2021Bexar County, Texas

NWS Austin/San Antonio, TX issued this flash flood warning at May 1, 2021, 12:09 PM CDT for Bexar County, Texas. It was in force for 4 hr. 8 reports 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: May 1, 2021, 12:09 PM CDT (17:09 UTC)
Expired: May 1, 2021, 4:15 PM CDT
In force: 4 hr
Issued by: NWS Austin/San Antonio, TX
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Bexar County, TX

The radar

The Austin/San Antonio radar (KEWX), 42 km from the middle of the area, began a volume at 17:13 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
May 1, 12:48 PM CDT	FLASH FLOOD	5 Ssw Sea World, TX	LOW-WATER CROSSING FLOODED ON GROSENBACHER RD NORTH OF US HIGHWAY 90. APPROXIMATELY 1 TO 2 FEET OF WATER ON THE ROADWAY.
May 1, 1:00 PM CDT	FLASH FLOOD	4 W Sea World, TX	PUBLIC REPORT OF LOW WATER CROSSING FLOODED ALONG BAR-J ROAD.
May 1, 1:05 PM CDT	FLASH FLOOD	5 S San Antonio, TX	PUBLIC REPORT OF VEHICLES STRANDED NEAR THE INTERSECTION OF SOUTH FLORES STREET AND SOUTHEAST MILITARY DRIVE.
May 1, 1:06 PM CDT	FLASH FLOOD	2 Ssw San Antonio, TX	I-35 AT NOGALITAS ST. FLOODED AND VEHICLES ARE STRANDED.
May 1, 1:16 PM CDT	FLASH FLOOD	San Antonio, TX	SEVERAL WATER RESCUES/EVACUATIONS OCCURRING ACROSS THE CITY LIMITS OF SAN ANTONIO.
May 1, 1:41 PM CDT	FLASH FLOOD	4 Ene China Grove, TX	SEVERAL LOW-WATER CROSSINGS FLOODED WITH 1 TO 2 FEET OF WATER DEPTH ACROSS EASTERN PORTIONS OF BEXAR COUNTY.
May 1, 1:47 PM CDT	FLASH FLOOD	Balcones Heights, TX	REPORT FROM MPING: ROAD CLOSED AND/OR VEHICLES STRANDED.
May 1, 2:15 PM CDT	FLASH FLOOD	4 E China Grove, TX	LOW WATER CROSSING ON MACAWAY ROAD NEAR RAKOWITZ ROAD COMPLETELY FLOODED WITH AT LEAST 3 FEET OF FLOWING WATER.

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 12:00Z, 5.2 hours before the alert went out and 232 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: 214 J/kg
Mixed-layer CIN: -33 J/kg
Mixed-layer LCL: 629 m above ground
0-6 km bulk shear: 49 kt
0-1 km storm-relative helicity: 74 m²/s²
0-3 km storm-relative helicity: 196 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.4

Open this sounding in Storm Lab

The text

As transmitted.

800 
WGUS54 KEWX 011709
FFWEWX
TXC029-012015-
/O.NEW.KEWX.FF.W.0007.210501T1709Z-210501T2015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Austin/San Antonio TX
1209 PM CDT Sat May 1 2021

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

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

* Until 315 PM CDT.

* At 1209 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain moving into the warned area from the west. The expected 
  rainfall rate is 1 to 2.5 inches in 1 hour. Additional rainfall 
  amounts of 1 to 2 inches are possible in the warned area. The area 
  is saturated and any additional heavy rainfall will lead to rapid 
  run off. 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, Schertz, Cibolo, Universal City, Live Oak, Selma, San 
  Antonio Int Airport, Stinson Municipal Airport, Randolph AFB, Leon 
  Valley, Helotes, Fair Oaks Ranch, Kirby, Alamo Heights, Windcrest, 
  Terrell Hills, Bulverde, Shavano Park, Hollywood Park and Cross 
  Mountain.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 2925 9880 2967 9881 2972 9878 2975 9853
      2974 9845 2972 9844 2975 9841 2972 9838
      2973 9835 2972 9834 2970 9838 2967 9838
      2956 9830 2955 9825 2949 9818 2950 9818
      2947 9812 2911 9841

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...1-2.5 INCHES IN 1 HOUR

$$

RUNYEN

2 follow-up statements

097 
WGUS74 KEWX 011830
FFSEWX

Flash Flood Statement
National Weather Service Austin/San Antonio TX
130 PM CDT Sat May 1 2021

TXC029-012015-
/O.CON.KEWX.FF.W.0007.000000T0000Z-210501T2015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bexar TX-
130 PM CDT Sat May 1 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 315 PM CDT THIS 
AFTERNOON FOR BEXAR COUNTY...

At 130 PM CDT, Local law enforcement reported numerous roads 
flooding across Bexar County and the San Antonio metro area as well 
as some high water rescues taking place. Please avoid travel. Flash 
flooding is ongoing.

HAZARD...Life threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Law enforcement reported.

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, Schertz, Cibolo, Universal City, Live Oak, Selma, San 
  Antonio Int Airport, Stinson Municipal Airport, Randolph AFB, Leon 
  Valley, Helotes, Fair Oaks Ranch, Kirby, Alamo Heights, Windcrest, 
  Terrell Hills, Bulverde, Shavano Park, Hollywood Park and Cross 
  Mountain.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 2925 9880 2967 9881 2972 9878 2975 9853
      2974 9845 2972 9844 2975 9841 2972 9838
      2973 9835 2972 9834 2970 9838 2967 9838
      2956 9830 2955 9825 2949 9818 2950 9818
      2947 9812 2911 9841

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...1-2.5 INCHES IN 1 HOUR

$$

RUNYEN

649 
WGUS54 KEWX 012000
FFWEWX
TXC029-012115-
/O.EXT.KEWX.FF.W.0007.000000T0000Z-210501T2115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Austin/San Antonio TX
300 PM CDT Sat May 1 2021

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

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

* Until 415 PM CDT.

* At 300 PM CDT, Local law enforcement reported several roads still 
  flooded across Bexar County and the San Antonio metro area. Please 
  avoid travel. Flash flooding is ongoing.

  HAZARD...Life threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Law enforcement reported.

  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, Schertz, Cibolo, Universal City, Live Oak, Selma, San 
  Antonio Int Airport, Stinson Municipal Airport, Randolph AFB, Leon 
  Valley, Helotes, Fair Oaks Ranch, Kirby, Alamo Heights, Windcrest, 
  Terrell Hills, Bulverde, Shavano Park, Hollywood Park and Cross 
  Mountain.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 2925 9880 2967 9881 2972 9878 2975 9853
      2974 9845 2972 9844 2975 9841 2972 9838
      2973 9835 2972 9834 2970 9838 2967 9838
      2956 9830 2955 9825 2949 9818 2950 9818
      2947 9812 2911 9841

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

RUNYEN

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 30, 8:01 PM CDT	Flash Flood Warning Considerable damage threat	EWX	Comal	2 hr
Apr 30, 8:17 PM CDT	Special Weather Statement	EWX	Terrell	28 min
Apr 30, 8:22 PM CDT	Areal Flood Advisory	EWX	Bexar, Guadalupe, Wilson	50 min
Apr 30, 9:12 PM CDT	Flash Flood Warning Considerable damage threat	EWX	Bexar, Guadalupe, Wilson	3 hr
Apr 30, 11:59 PM CDT	Areal Flood Advisory	EWX	Lavaca	3 hr
May 1, 3:09 AM CDT	Areal Flood Advisory	EWX	Lavaca	51 min
May 1, 3:57 AM CDT	Flash Flood Warning Considerable damage threat	EWX	Lavaca	3 hr
May 1, 8:10 AM CDT	Special Weather Statement	EWX	Maverick	35 min
May 1, 8:23 AM CDT	Special Weather Statement	EWX	Dimmit	52 min
May 1, 9:10 AM CDT	Special Weather Statement	EWX	Dimmit	35 min
May 1, 9:24 AM CDT	Special Weather Statement	EWX	Zavala	36 min
May 1, 9:55 AM CDT	Areal Flood Advisory	EWX	Kinney, Maverick, Uvalde, Val Verde, Zavala	3 hr
May 1, 10:02 AM CDT	Special Weather Statement	EWX	Uvalde, Zavala	43 min
May 1, 10:36 AM CDT	Special Weather Statement	EWX	Frio, Medina, Uvalde	54 min
May 1, 10:49 AM CDT	Areal Flood Advisory	EWX	Bandera, Frio, Medina	3 hr
May 1, 11:15 AM CDT	Flash Flood Warning Considerable damage threat	EWX	Medina, Uvalde	4 hr
May 1, 11:18 AM CDT	Areal Flood Advisory	EWX	Uvalde	3 hr
May 1, 11:31 AM CDT	Special Weather Statement	EWX	Atascosa, Bexar, Medina	59 min
May 1, 11:44 AM CDT	Areal Flood Advisory	EWX	Bandera, Gillespie, Kerr, Medina	4 hr
May 1, 12:01 PM CDT	Areal Flood Advisory	EWX	Atascosa	3 hr
May 1, 12:30 PM CDT	Special Weather Statement	EWX	Atascosa, Bexar, Wilson	45 min
May 1, 12:40 PM CDT	River Flood Warning	EWX	Bexar	32 hr
May 1, 1:03 PM CDT	Areal Flood Advisory	EWX	Comal	3 hr
May 1, 1:14 PM CDT	Special Weather Statement	EWX	Comal, Guadalupe, Karnes, Wilson	61 min
May 1, 1:22 PM CDT	Flash Flood Warning Considerable damage threat	EWX	Comal, Guadalupe, Wilson	3 hr
May 1, 1:52 PM CDT	Areal Flood Advisory	EWX	Gillespie, Kendall	3 hr
May 1, 2:07 PM CDT	River Flood Warning	EWX	Bexar, Wilson	41 hr
May 1, 2:07 PM CDT	Special Weather Statement	EWX	Caldwell, Gonzales, Guadalupe	38 min
May 1, 2:27 PM CDT	Flash Flood Warning Considerable damage threat	EWX	Caldwell, Hays	3 hr
May 1, 2:44 PM CDT	Areal Flood Advisory	EWX	Gonzales	3 hr
May 1, 2:58 PM CDT	Flash Flood Warning Considerable damage threat	EWX	Bastrop, Travis	3 hr
May 1, 3:11 PM CDT	Flash Flood Warning Considerable damage threat	EWX	Gonzales	3 hr
May 1, 3:39 PM CDT	Areal Flood Advisory	EWX	Lee, Williamson	3 hr
May 1, 4:11 PM CDT	Flash Flood Warning Considerable damage threat	EWX	Williamson	3 hr
May 1, 4:14 PM CDT	Areal Flood Advisory	EWX	Bexar	2 hr
May 1, 4:25 PM CDT	Areal Flood Advisory	EWX	Lavaca	3 hr
May 1, 4:31 PM CDT	Special Weather Statement	EWX	Bandera, Kerr	44 min
May 1, 6:13 PM CDT	Areal Flood Advisory	EWX	Bandera, Gillespie, Kendall, Kerr	3 hr
May 1, 6:53 PM CDT	Areal Flood Advisory	EWX	Gillespie, Kendall	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.