Alert archive / Texas / Flash Flood Warnings in 2012

Flash Flood Warning 40, NWS Austin/San Antonio, TX

May 11, 2012Hays County, Texas

NWS Austin/San Antonio, TX issued this flash flood warning at May 11, 2012, 2:37 AM CDT for Hays County, Texas. It was in force for 113 min. 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
May 11, 2012, 2:37 AM CDT (07:37 UTC)
Expired
May 11, 2012, 4:30 AM CDT
In force
113 min
Issued by
NWS Austin/San Antonio, TX
Area
Storm-based polygon
Flood severity
None

County Hays County, TX

The radar

The Austin/San Antonio radar (KEWX), 43 km from the middle of the area, began a volume at 07:38 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
May 11, 3:00 AM CDTFLASH FLOOD3 Sse Driftwood, TXSEVERAL ROADS CLOSED DUE TO FLOODED LOW WATER CROSSINGS.

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, 7.6 hours before the alert went out and 268 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 2012-05-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2214 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 2012-05-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 204 square meters per square second.19395878Sfc1 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
2214 J/kg
Mixed-layer CIN
-8 J/kg
Mixed-layer LCL
636 m above ground
0-6 km bulk shear
54 kt
0-1 km storm-relative helicity
204 m²/s²
0-3 km storm-relative helicity
274 m²/s²
Significant tornado parameter
3.4
Supercell composite
14.5

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

191 
WGUS54 KEWX 110737
FFWEWX
TXC209-110930-
/O.NEW.KEWX.FF.W.0040.120511T0737Z-120511T0930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
237 AM CDT FRI MAY 11 2012

THE NATIONAL WEATHER SERVICE IN AUSTIN SAN ANTONIO HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CENTRAL HAYS COUNTY...

* UNTIL 430 AM CDT.

* AT 232 AM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS HAVE       
  DETERMINED THAT RUNOFF FROM EARLIER RAINS HAS RESULTED IN FLOODING
  ALONG ONION CREEK. AT 2 AM THE GAGE LOCATED ON ONION CREEK NEAR
  DRIFTWOOD MEASURED 9.6 FEET. FLOOD STAGE IS 7 FT. MINOR FLOODING
  WILL CONTINUE ALONG ONION CREEK FOR THE NEXT 2 HOURS. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IT IS HARD TO RECOGNIZE THE DANGERS OF FLOODING AT NIGHT. IF FLOOD
WATERS RISE ACT QUICKLY. DO NOT STAY IN FLOOD PRONE AREAS.

&&

LAT...LON 3008 9787 3003 9790 3008 9803 3013 9801

$$

The office that day

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

IssuedProductOfficeCountiesLasted
May 10, 7:21 PM CDTTornado WarningEWXDimmit, Frio, Zavala24 min
May 10, 7:59 PM CDTRiver Flood WarningEWXKerr18 hr
May 10, 8:02 PM CDTFlash Flood WarningEWXHays, Travis, Williamson118 min
May 10, 8:26 PM CDTSevere Thunderstorm WarningEWXTravis, Williamson49 min
May 10, 8:32 PM CDTRiver Flood WarningEWXVal Verde30 hr
May 10, 8:34 PM CDTAreal Flood AdvisoryEWXBexar116 min
May 10, 9:10 PM CDTFlash Flood WarningEWXBexar, Comal, Guadalupe, Hays3 hr
May 10, 9:59 PM CDTAreal Flood AdvisoryEWXBastrop, Caldwell, Comal, Guadalupe, Hays, Lee and 2 more2 hr
May 10, 10:42 PM CDTFlash Flood WarningEWXBastrop, Caldwell, Guadalupe, Hays, Lee, Travis and 1 more4 hr
May 11, 12:06 AM CDTFlash Flood WarningEWXBexar, Comal3 hr

Nearby

Flash Flood Warnings in Texas, 2012Every flash flood warning in 2012

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.