Alert archive / Texas / Flash Flood Warnings in 2018

Flash Flood Warning 22, NWS Austin/San Antonio, TX

September 3, 2018Bexar County, Comal County, Texas

NWS Austin/San Antonio, TX issued this flash flood warning at Sep 3, 2018, 11:48 PM CDT for Bexar County, Comal 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
Sep 3, 2018, 11:48 PM CDT (04:48 UTC)
Expired
Sep 4, 2018, 2:45 AM CDT
In force
3 hr
Issued by
NWS Austin/San Antonio, TX
Area
Storm-based polygon
Flood severity
None

Counties Bexar County, TX, Comal County, TX

The radar

The Austin/San Antonio radar (KEWX), 48 km from the middle of the area, began a volume at 04:49 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
Sep 4, 1:00 AM CDTFLASH FLOODBulverde, TXA LOW WATER CROSSING ON CIBOLO CREEK WAS FLOODED TO A DEPTH OF NEARLY 2 FEET ABOVE THE ROADWAY.

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 (KDLF), launched 00:00Z, 4.8 hours before the alert went out and 228 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 00:00Z on 2018-09-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 966 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 00:00Z on 2018-09-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 41 square meters per square second.193958Sfc1 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
966 J/kg
Mixed-layer CIN
-30 J/kg
Mixed-layer LCL
1374 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
41 m²/s²
0-3 km storm-relative helicity
37 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.1

Open this sounding in Storm Lab

The text

As transmitted.

491 
WGUS54 KEWX 040448
FFWEWX
TXC029-091-040745-
/O.NEW.KEWX.FF.W.0022.180904T0448Z-180904T0745Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Austin/San Antonio TX
1148 PM CDT MON SEP 3 2018

The National Weather Service in Austin San Antonio has issued a

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

* Until 245 AM CDT

* At 1145 PM CDT, Doppler radar indicated thunderstorms continuing 
  to produce moderate to heavy rain across the northern part of 
  Bexar and western Comal Counties. Up to seven inches of rain have 
  already fallen between Timberwood Park and Hollywood Park areas. 
  Flash flooding is expected to continue as additional one inch of 
  rainfall is possible for the next couple of hours.

* Some locations that will experience flooding include...
  San Antonio, Canyon Lake, Helotes, Fair Oaks Ranch, Bulverde,
  Garden Ridge, Shavano Park, Hollywood Park, Cross Mountain,
  Smithson Valley, Timberwood Park, Leon Springs, The Dominion,
  Spring Branch, Government Canyon State Natural Area, Guadalupe
  River State Park, Hill Country Village, Grey Forest, Anhalt and
  Specht Store.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 2991 9839 2977 9818 2963 9833 2952 9878
      2968 9878 2975 9865 2975 9864 2979 9860

$$
1 follow-up statement
095 
WGUS74 KEWX 040744
FFSEWX

Flash Flood Statement
National Weather Service Austin/San Antonio TX
244 AM CDT TUE SEP 4 2018

TXC029-091-040748-
/O.EXP.KEWX.FF.W.0022.000000T0000Z-180904T0745Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bexar TX-Comal TX-
244 AM CDT TUE SEP 4 2018

...THE FLASH FLOOD WARNING FOR NORTHWESTERN BEXAR AND CENTRAL COMAL
COUNTIES WILL EXPIRE AT 245 AM CDT...

The heavy rain has ended. Flood waters have receded most areas and 
additional flash flooding is not expected within the next couple of 
hours. Please continue to monitor weather conditions for new 
development later tonight through Tuesday morning.

LAT...LON 2991 9839 2977 9818 2963 9833 2952 9878
      2968 9878 2975 9865 2975 9864 2979 9860

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 3, 7:30 PM CDTAreal Flood AdvisoryEWXBexar, Comal3 hr
Sep 3, 7:57 PM CDTSpecial Weather StatementEWXZavala48 min
Sep 3, 8:43 PM CDTFlash Flood WarningEWXBexar, Comal3 hr
Sep 3, 8:50 PM CDTFlash Flood WatchEWXAtascosa, Bandera, Bexar, Dimmit, Frio, Kinney and 5 more16 hr
Sep 3, 9:46 PM CDTAreal Flood AdvisoryEWXKinney, Uvalde3 hr
Sep 3, 10:04 PM CDTFlash Flood WarningEWXBexar3 hr
Sep 3, 11:23 PM CDTAreal Flood AdvisoryEWXBandera3 hr
Sep 3, 11:25 PM CDTAreal Flood AdvisoryEWXDimmit3 hr
Sep 3, 11:38 PM CDTRiver Flood WarningEWXBexar33 hr
Sep 4, 12:06 AM CDTRiver Flood WarningEWXBexar3 hr
Sep 4, 12:57 AM CDTFlash Flood WarningEWXUvalde6 hr
Sep 4, 1:08 AM CDTFlash Flood WarningEWXBexar112 min
Sep 4, 2:02 AM CDTAreal Flood AdvisoryEWXKinney, Uvalde3 hr
Sep 4, 3:07 AM CDTFlash Flood WarningEWXBexar3 hr
Sep 4, 3:30 AM CDTAreal Flood AdvisoryEWXMaverick3 hr
Sep 4, 4:14 AM CDTRiver Flood WarningEWXUvalde4 hr
Sep 4, 4:39 AM CDTAreal Flood AdvisoryEWXFrio, Medina3 hr
Sep 4, 5:02 AM CDTAreal Flood AdvisoryEWXKinney, Maverick, Uvalde, Zavala3 hr
Sep 4, 5:09 AM CDTAreal Flood AdvisoryEWXAtascosa, Frio, Medina3 hr
Sep 4, 5:59 AM CDTFlash Flood WarningEWXBexar4 hr
Sep 4, 9:30 AM CDTRiver Flood WarningEWXBexar11 hr
Sep 4, 9:30 AM CDTRiver Flood WarningEWXBexar, Wilson33 hr
Sep 4, 9:30 AM CDTRiver Flood WarningEWXBexar28 hr
Sep 4, 9:58 AM CDTAreal Flood AdvisoryEWXBexar2 hr
Sep 4, 11:23 AM CDTAreal Flood AdvisoryEWXMedina, Uvalde112 min

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.