Alert archive / Texas / Flash Flood Warnings in 2012

Flash Flood Warning 11, NWS Austin/San Antonio, TX

February 3, 2012Williamson County, Texas

NWS Austin/San Antonio, TX issued this flash flood warning at Feb 3, 2012, 10:36 PM CST for Williamson County, Texas. It was in force for 114 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: Feb 3, 2012, 10:36 PM CST (04:36 UTC)
Expired: Feb 4, 2012, 12:30 AM CST
In force: 114 min
Issued by: NWS Austin/San Antonio, TX
Area: Storm-based polygon
Flood severity: None

County Williamson County, TX

The radar

The Ft Hood radar (KGRK), 17 km from the middle of the area, began a volume at 04:37 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
Feb 3, 11:00 PM CST	FLASH FLOOD	Thrall, TX	SEVERAL ROADS CLOSED IN TAYLOR... THRALL AND COUPLAND DUE TO HIGH WATER.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Fort Worth, TX (KFWD), launched 00:00Z, 4.6 hours before the alert went out and 251 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: 1201 J/kg
Mixed-layer CIN: -18 J/kg
Mixed-layer LCL: 959 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 209 m²/s²
0-3 km storm-relative helicity: 218 m²/s²
Significant tornado parameter: 1.2
Supercell composite: 8.9

Open this sounding in Storm Lab

The text

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

219 
WGUS54 KEWX 040436
FFWEWX
TXC491-040630-
/O.NEW.KEWX.FF.W.0011.120204T0436Z-120204T0630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1036 PM CST FRI FEB 3 2012

THE NATIONAL WEATHER SERVICE IN AUSTIN SAN ANTONIO HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHEASTERN WILLIAMSON COUNTY...

* UNTIL 1230 AM CST.

* AT 1036 PM CST...NATIONAL WEATHER SERVICE METEOROLOGISTS HAVE      
  DETERMINED THAT RAINFALL ESTIMATES FROM DOPPLER RADAR INDICATE A   
  SLOW MOVING THUNDERSTORM WITH VERY HEAVY RAINFALL ACROSS EASTERN   
  WILLIAMSON COUNTY BETWEEN TAYLOR...THRALL AND COUPLAND. RAINFALL   
  RATES OF 3 TO 4 INCHES PER HOUR HAVE BEEN COMMON WITH THIS SLOW    
  MOVING STORM.

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
  OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  TAYLOR...COUPLAND...GRANGER DAM AND THRALL.

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 3073 9726 3063 9721 3046 9715 3040 9734
      3044 9740 3044 9741 3045 9745 3052 9752
      3075 9730 3075 9728

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
Feb 3, 9:18 PM CST	Areal Flood Advisory	EWX	Bexar	2 hr
Feb 3, 9:45 PM CST	Areal Flood Advisory	EWX	Williamson	105 min
Feb 3, 10:02 PM CST	Flash Flood Warning	EWX	Bexar	118 min
Feb 3, 10:15 PM CST	Severe Thunderstorm Warning	EWX	Bexar	30 min
Feb 3, 10:38 PM CST	Severe Thunderstorm Warning	EWX	Bexar	37 min
Feb 3, 10:51 PM CST	Flash Flood Warning	EWX	Bexar	3 hr
Feb 3, 11:15 PM CST	Severe Thunderstorm Warning	EWX	Bexar, Guadalupe	60 min
Feb 4, 12:15 AM CST	Severe Thunderstorm Warning	EWX	Bexar, Guadalupe, Wilson	45 min
Feb 4, 12:57 AM CST	Areal Flood Advisory	EWX	Burnet	2 hr
Feb 4, 1:07 AM CST	Areal Flood Advisory	EWX	Hays, Travis	113 min
Feb 4, 1:25 AM CST	Flash Flood Warning	EWX	Travis, Williamson	3 hr
Feb 4, 1:54 AM CST	Areal Flood Advisory	EWX	Bexar, Guadalupe, Wilson	2 hr
Feb 4, 2:32 AM CST	Areal Flood Advisory	EWX	Bandera, Medina	118 min
Feb 4, 2:42 AM CST	Flash Flood Warning	EWX	Hays, Travis	3 hr
Feb 4, 3:11 AM CST	Areal Flood Advisory	EWX	Bandera, Bexar, Medina	109 min
Feb 4, 3:27 AM CST	Areal Flood Advisory	EWX	Bastrop, Caldwell, Hays, Lee, Travis	2 hr
Feb 4, 4:06 AM CST	Areal Flood Advisory	EWX	Bexar, Comal, Guadalupe	114 min

Nearby

Flash Flood Warnings in Texas, 2012 Every 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.