Alert archive / Texas / Flash Flood Warnings in 2018

Flash Flood Warning 16, NWS Austin/San Antonio, TX

August 12, 2018Bexar County, Texas

NWS Austin/San Antonio, TX issued this flash flood warning at Aug 12, 2018, 8:30 PM CDT for Bexar County, Texas. It was in force for 3 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 12, 2018, 8:30 PM CDT (01:30 UTC)
Expired
Aug 12, 2018, 11:30 PM CDT
In force
3 hr
Issued by
NWS Austin/San Antonio, TX
Area
Storm-based polygon
Flood severity
None

County Bexar County, TX

The radar

The Austin/San Antonio radar (KEWX), 65 km from the middle of the area, began a volume at 01:31 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 12, 10:00 PM CDTFLASH FLOOD7 Sse San Antonio, TXSEVERAL ROADS CLOSED DUE TO FLOODING SEEN ON BEXARFLOOD.ORG.

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, 1.5 hours before the alert went out and 212 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 2018-08-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2682 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 2018-08-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 12 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
2682 J/kg
Mixed-layer CIN
-12 J/kg
Mixed-layer LCL
955 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
12 m²/s²
0-3 km storm-relative helicity
42 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

599 
WGUS54 KEWX 130130
FFWEWX
TXC029-130430-
/O.NEW.KEWX.FF.W.0016.180813T0130Z-180813T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Austin/San Antonio TX
830 PM CDT SUN AUG 12 2018

The National Weather Service in Austin San Antonio has issued a

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

* Until 1130 PM CDT

* At 830 PM CDT, Doppler radar indicated thunderstorms producing
  heavy rain across the warned area. Up to two inches of rain have
  already fallen. Flash flooding is expected to begin shortly.

* Some locations that will experience flooding include...
  San Antonio, Stinson Municipal Airport, St. Hedwig, Elmendorf,
  China Grove, Lackland AFB, Sandy Oaks, Von Ormy, Buena Vista,
  Martinez, Mitchell Lake, Losoya, Southton, Sayers, Thelma, Brooks
  City Base and Braunig Lake.

Additional rainfall amounts of 2 to 3 inches are possible in the 
warned area.

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 2944 9878 2943 9822 2916 9839 2915 9852

$$

MSL
2 follow-up statements
984 
WGUS74 KEWX 130212
FFSEWX

Flash Flood Statement
National Weather Service Austin/San Antonio TX
912 PM CDT SUN AUG 12 2018

TXC029-130430-
/O.CON.KEWX.FF.W.0016.000000T0000Z-180813T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bexar TX-
912 PM CDT SUN AUG 12 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1130 PM CDT FOR
SOUTHERN BEXAR COUNTY...

At 910 PM CDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Three to four inches of rain have 
already fallen. Flash flooding will continue until the water has had 
a chance to drain off.

Some locations that will experience flooding include...
San Antonio, Stinson Municipal Airport, St. Hedwig, Elmendorf, China
Grove, Lackland AFB, Sandy Oaks, Von Ormy, Buena Vista, Martinez,
Mitchell Lake, Losoya, Southton, Sayers, Thelma, Brooks City Base and
Braunig Lake.

Additional rainfall amounts up to one to two inches are possible in 
the warned area. 

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 2944 9878 2943 9822 2916 9839 2915 9852

$$

MSL
005 
WGUS74 KEWX 130425
FFSEWX

Flash Flood Statement
National Weather Service Austin/San Antonio TX
1125 PM CDT SUN AUG 12 2018

TXC029-130435-
/O.EXP.KEWX.FF.W.0016.000000T0000Z-180813T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bexar TX-
1125 PM CDT SUN AUG 12 2018

...THE FLASH FLOOD WARNING FOR SOUTHERN BEXAR COUNTY WILL EXPIRE AT
1130 PM CDT...

The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed any remaining road closures.

LAT...LON 2944 9878 2943 9822 2916 9839 2915 9852

$$

HAMPSHIRE

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 12, 8:50 PM CDTSpecial Weather StatementEWXBexar40 min
Aug 12, 9:29 PM CDTAreal Flood AdvisoryEWXAtascosa, Bexar, Medina2 hr
Aug 12, 9:48 PM CDTFlash Flood WarningEWXBexar, Medina87 min
Aug 13, 10:14 AM CDTAreal Flood AdvisoryEWXEdwards, Kerr, Real3 hr

Nearby

Flash Flood Warnings in Texas, 2018Every flash flood warning in 2018

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.