Alert archive / Texas / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 64, NWS Austin/San Antonio, TX

May 7, 2012Llano County, Texas

NWS Austin/San Antonio, TX issued this severe thunderstorm warning at May 7, 2012, 4:47 PM CDT for Llano County, Texas. It was in force for 58 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 7, 2012, 4:47 PM CDT (21:47 UTC)
Expired: May 7, 2012, 5:45 PM CDT
In force: 58 min
Issued by: NWS Austin/San Antonio, TX
Area: Storm-based polygon

County Llano County, TX

The radar

The Ft Hood radar (KGRK), 140 km from the middle of the area, began a volume at 21:47 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
May 7, 5:15 PM CDT	HAIL 1	6 Wsw Llano, TX	PEA TO NEAR QUARTER SIZE HAIL NEAR LLANO.

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

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
May 7, 3:27 PM CDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Del Rio, TX (KDRT), launched 12:00Z, 9.8 hours before the alert went out and 252 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: 3104 J/kg
Mixed-layer CIN: -170 J/kg
Mixed-layer LCL: 1000 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 122 m²/s²
0-3 km storm-relative helicity: 68 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

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

242 
WUUS54 KEWX 072147
SVREWX
TXC299-072245-
/O.NEW.KEWX.SV.W.0064.120507T2147Z-120507T2245Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
447 PM CDT MON MAY 7 2012

THE NATIONAL WEATHER SERVICE IN AUSTIN SAN ANTONIO HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHWESTERN LLANO COUNTY...

* UNTIL 545 PM CDT.

* AT 445 PM CDT...NWS METEOROLOGISTS HAVE DETECTED A SEVERE
  THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND DAMAGING
  WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED 6 MILES SOUTH OF
  FIELD CREEK...OR 16 MILES WEST OF LLANO...AND MOVING EAST AT 10 
  MPH.

* SOME LOCATIONS IN THE WARNING INCLUDE VALLEY SPRING.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE
IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD
TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.

&&

LAT...LON 3068 9870 3075 9897 3086 9898 3092 9897
      3093 9896 3093 9878 3093 9868
TIME...MOT...LOC 2147Z 256DEG 9KT 3082 9897

$$

1 follow-up statement

182 
WWUS54 KEWX 072212
SVSEWX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
512 PM CDT MON MAY 7 2012

TXC299-072245-
/O.CON.KEWX.SV.W.0064.000000T0000Z-120507T2245Z/
LLANO TX-
512 PM CDT MON MAY 7 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 545 PM CDT
FOR NORTHWESTERN LLANO COUNTY...

AT 506 PM CDT...NWS METEOROLOGISTS CONTINUED TO DETECT A SEVERE
THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND DAMAGING
WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED NEAR FIELD
CREEK...OR 15 MILES WEST OF LLANO...MOVING EAST AT 10 MPH.

SOME LOCATIONS IN THE WARNING AREA INCLUDE VALLEY SPRING.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 1100 PM CDT
MONDAY EVENING FOR SOUTH CENTRAL TEXAS.

&&

LAT...LON 3068 9870 3075 9897 3086 9898 3092 9897
      3093 9896 3093 9878 3093 9868
TIME...MOT...LOC 2209Z 256DEG 9KT 3083 9891

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
May 6, 7:09 PM CDT	Areal Flood Advisory	EWX	Llano	111 min
May 6, 7:33 PM CDT	Severe Thunderstorm Warning	EWX	Llano	42 min
May 7, 3:28 AM CDT	Flash Flood Watch	EWX	Bandera, Bexar, Blanco, Burnet, Comal, Edwards and 12 more	37 hr
May 7, 5:10 PM CDT	Tornado Warning	EWX	Llano	35 min
May 7, 5:23 PM CDT	Severe Thunderstorm Warning	EWX	Llano	37 min
May 7, 5:32 PM CDT	Tornado Warning	EWX	Gillespie, Llano	28 min
May 7, 5:43 PM CDT	Tornado Warning	EWX	Llano	32 min
May 7, 5:57 PM CDT	Severe Thunderstorm Warning	EWX	Blanco, Burnet, Gillespie, Llano	63 min
May 7, 6:08 PM CDT	Areal Flood Advisory	EWX	Llano	112 min
May 7, 6:49 PM CDT	Severe Thunderstorm Warning	EWX	Blanco, Gillespie, Kendall	56 min
May 7, 6:51 PM CDT	Areal Flood Advisory	EWX	Gillespie	2 hr

Nearby

Severe Thunderstorm Warnings in Texas, 2012 Every severe thunderstorm 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.