Alert archive / Texas / Flash Flood Warnings in 2018

Flash Flood Warning 67, NWS Austin/San Antonio, TX

December 27, 2018Hays County, Travis County, Williamson County, Texas

NWS Austin/San Antonio, TX issued this flash flood warning at Dec 27, 2018, 12:38 AM CST for Hays County, Travis County, Williamson County, Texas. It was in force for 3 hr. 3 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: Dec 27, 2018, 12:38 AM CST (06:38 UTC)
Expired: Dec 27, 2018, 3:30 AM CST
In force: 3 hr
Issued by: NWS Austin/San Antonio, TX
Area: Storm-based polygon
Flood severity: None

Counties Hays County, TX, Travis County, TX, Williamson County, TX

The radar

The Ft Hood radar (KGRK), 31 km from the middle of the area, began a volume at 06:41 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
Dec 27, 1:00 AM CST	FLASH FLOOD	5 S Granger, TX	E SH 29 AT CR 337 NEAR TAYLOR IS CLOSED DUE TO WATER OVER THE ROADWAYS.
Dec 27, 1:11 AM CST	FLASH FLOOD	1 Nw Brushy Creek, TX	THE WALSH DRIVE CROSSING AT BRUSHY CREEK NEAR BRUSHY CREEK ROAD IS CLOSED DUE TO FLOODING.
Dec 27, 1:31 AM CST	FLASH FLOOD	4 Ssw Jollyville, TX	TWO VEHICLES IN HIGH WATER AT THE 6000 BLOCK OF SPICEWOOD SPRINGS ROAD. MULTIPLE PEOPLE NEEDING RESCUED.

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, 6.6 hours before the alert went out and 306 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: 2419 J/kg
Mixed-layer CIN: -13 J/kg
Mixed-layer LCL: 483 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 181 m²/s²
0-3 km storm-relative helicity: 267 m²/s²
Significant tornado parameter: 3.3
Supercell composite: 20.1

Open this sounding in Storm Lab

The text

As transmitted.

701 
WGUS54 KEWX 270638
FFWEWX
TXC209-453-491-270930-
/O.NEW.KEWX.FF.W.0067.181227T0638Z-181227T0930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Austin/San Antonio TX
1238 AM CST THU DEC 27 2018

The National Weather Service in Austin San Antonio has issued a

* Flash Flood Warning for...
  Williamson County in south central Texas...
  Northern Hays County in south central Texas...
  Travis County in south central Texas...

* Until 330 AM CST

* At 1237 AM CST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area which covers the majority of the 
  Austin metro area. Up to three inches of rain have already fallen. 
  Flash flooding is expected to begin shortly.

* Some locations that will experience flooding include...
  Austin, Round Rock, Cedar Park, Georgetown, Pflugerville, Taylor,
  Buda, Elgin, Dripping Springs, Granger, Tanglewood Forest, Anderson
  Mill, Windemere, Austin Bergstrom Int Airport, Serenada, Leander,
  Hutto, Lakeway, Manor and Lago Vista.

Additional rainfall amounts of between 1/2 and 1 inch are expected 
in the warned area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

In hilly terrain there are hundreds of low water crossings which are
potentially dangerous in heavy rain. Do not attempt to cross flooded
roads. Find an alternate route.

&&

LAT...LON 3074 9727 3046 9716 3040 9734 3042 9737
      3036 9740 2999 9803 3022 9821 3061 9782
      3081 9747

$$

MO

The office that day

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

Issued	Product	Office	Counties	Lasted
Dec 26, 6:09 PM CST	Severe Thunderstorm Warning	EWX	Edwards, Kinney, Val Verde	66 min
Dec 26, 7:01 PM CST	Special Weather Statement	EWX	Kinney	44 min
Dec 26, 7:06 PM CST	Severe Thunderstorm Warning	EWX	Edwards, Kinney, Val Verde	54 min
Dec 26, 7:10 PM CST	Severe Thunderstorm Warning	EWX	Edwards, Kerr, Real	65 min
Dec 26, 7:39 PM CST	Special Weather Statement	EWX	Kinney	66 min
Dec 26, 8:01 PM CST	Severe Thunderstorm Warning	EWX	Bandera, Edwards, Kerr, Kinney, Real, Uvalde	78 min
Dec 26, 8:21 PM CST	Special Weather Statement	EWX	Burnet, Gillespie, Llano	54 min
Dec 26, 9:05 PM CST	Special Weather Statement	EWX	Bandera, Kendall, Kerr	40 min
Dec 26, 9:12 PM CST	Areal Flood Advisory	EWX	Burnet, Gillespie, Kerr, Llano	3 hr
Dec 26, 9:32 PM CST	Special Weather Statement	EWX	Blanco, Burnet, Gillespie, Williamson	58 min
Dec 26, 9:45 PM CST	Special Weather Statement	EWX	Bandera, Comal, Hays, Kendall, Medina, Uvalde	60 min
Dec 26, 9:54 PM CST	Severe Thunderstorm Warning	EWX	Williamson	32 min
Dec 26, 10:00 PM CST	Areal Flood Advisory	EWX	Bandera, Blanco, Kendall, Real, Uvalde	3 hr
Dec 26, 10:20 PM CST	Special Weather Statement	EWX	Blanco, Travis, Williamson	55 min
Dec 26, 10:25 PM CST	Severe Thunderstorm Warning	EWX	Williamson	35 min
Dec 26, 10:43 PM CST	Severe Thunderstorm Warning	EWX	Comal, Hays	32 min
Dec 26, 10:49 PM CST	Areal Flood Advisory	EWX	Hays, Travis, Williamson	5 hr
Dec 26, 11:06 PM CST	Special Weather Statement	EWX	Bandera, Bexar, Comal, Hays, Kendall, Medina	54 min
Dec 26, 11:19 PM CST	Special Weather Statement	EWX	Lee, Travis, Williamson	56 min
Dec 26, 11:44 PM CST	Areal Flood Advisory	EWX	Bexar, Comal, Medina	4 hr
Dec 27, 12:01 AM CST	Special Weather Statement	EWX	Bastrop, Bexar, Comal, Hays, Kendall, Medina	44 min
Dec 27, 12:03 AM CST	Special Weather Statement	EWX	Lee, Travis	42 min
Dec 27, 12:47 AM CST	Special Weather Statement	EWX	Blanco, Kendall	43 min
Dec 27, 12:52 AM CST	Areal Flood Advisory	EWX	Bastrop, Caldwell, Guadalupe, Lee	3 hr
Dec 27, 2:11 AM CST	Special Weather Statement	EWX	Comal	49 min
Dec 27, 2:16 AM CST	Special Weather Statement	EWX	Atascosa	44 min
Dec 27, 2:36 AM CST	Areal Flood Advisory	EWX	Fayette	114 min
Dec 27, 3:00 AM CST	Special Weather Statement	EWX	Wilson	60 min
Dec 27, 3:50 AM CST	Areal Flood Advisory	EWX	Hays, Travis, Williamson	115 min
Dec 27, 7:29 AM CST	River Flood Warning	EWX	Travis	18 hr
Dec 27, 7:29 AM CST	River Flood Warning	EWX	Travis	18 hr

Nearby

Flash Flood Warnings in Texas, 2018 Every 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.