Alert archive / Texas / Tornado Warnings in 2012

Tornado Warning 34, NWS Shreveport, LA

April 11, 2012Sabine County, San Augustine County, Texas

NWS Shreveport, LA issued this tornado warning at Apr 11, 2012, 4:01 PM CDT for Sabine County, San Augustine County, Texas. It was in force for 44 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Apr 11, 2012, 4:01 PM CDT (21:01 UTC)
Expired
Apr 11, 2012, 4:45 PM CDT
In force
44 min
Issued by
NWS Shreveport, LA
Area
Storm-based polygon

Counties Sabine County, TX, San Augustine County, TX

The radar

The Shreveport radar (KSHV), 105 km from the middle of the area, began a volume at 21:03 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.

The nearest sounding before it

Shreveport, LA (KSHV), launched 12:00Z, 9.0 hours before the alert went out and 109 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, Shreveport, LA at 12:00Z on 2012-04-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1015 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Shreveport, LA at 12:00Z on 2012-04-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 73 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
1015 J/kg
Mixed-layer CIN
-48 J/kg
Mixed-layer LCL
833 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
73 m²/s²
0-3 km storm-relative helicity
33 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.4

Open this sounding in Storm Lab

The text

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

308 
WFUS54 KSHV 112101
TORSHV
TXC403-405-112145-
/O.NEW.KSHV.TO.W.0034.120411T2101Z-120411T2145Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SHREVEPORT LA
401 PM CDT WED APR 11 2012

THE NATIONAL WEATHER SERVICE IN SHREVEPORT HAS ISSUED A

* TORNADO WARNING FOR...
  NORTHWESTERN SABINE COUNTY IN EASTERN TEXAS...
  NORTHEASTERN SAN AUGUSTINE COUNTY IN EASTERN TEXAS...

* UNTIL 445 PM CDT

* AT 353 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO NEAR BLAND      
  LAKE...MOVING SOUTHEAST AT 10 MPH.

* THE TORNADO WILL OTHERWISE REMAIN OVER MAINLY RURAL AREAS IN 
  NORTHEAST SAN AUGUSTINE AND NORTHWEST SABINE COUNTIES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF IN MOBILE HOMES OR VEHICLES...EVACUATE THEM AND GET INSIDE A
STURDY SHELTER. IF NO SHELTER IS AVAILABLE...LIE FLAT IN THE NEAREST
DITCH OR OTHER LOW SPOT AND COVER YOUR HEAD WITH YOUR HANDS.

&&

LAT...LON 3151 9388 3141 9404 3157 9414 3160 9405
TIME...MOT...LOC 2059Z 317DEG 6KT 3155 9406

$$

06
2 follow-up statements
714 
WWUS54 KSHV 112123
SVSSHV

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SHREVEPORT LA
423 PM CDT WED APR 11 2012

TXC403-405-112145-
/O.CON.KSHV.TO.W.0034.000000T0000Z-120411T2145Z/
SABINE TX-SAN AUGUSTINE TX-
423 PM CDT WED APR 11 2012

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 445 PM CDT FOR SAN
AUGUSTINE AND SABINE COUNTIES...

AT 418 PM CDT...USING DOPPLER RADAR...NATIONAL WEATHER SERVICE 
METEOROLOGISTS CONTINUED TO DETECT A SEVERE THUNDERSTORMS CAPABLE OF 
PRODUCING A TORNADO.  THIS THUNDERSTORMS WAS LOCATED OVER THE 
NORTHEAST CORNER OF SAN AUGUSTINE COUNTY...OR 5 MILES EAST OF 
SAN AUGUSTINE TEXAS...MOVING SOUTHEAST AT 10 MPH.

THE TORNADO WILL OTHERWISE REMAIN OVER MAINLY RURAL AREAS OF THE 
INDICATED COUNTIES IN NORTHEAST SAN AUGUSTINE COUNTY AND NORTHWEST 
SABINE COUNTY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IF YOU ARE CAUGHT OUTSIDE...SEEK SHELTER IN A NEARBY REINFORCED
BUILDING. AS A LAST RESORT...SEEK SHELTER IN A CULVERT...DITCH OR LOW
SPOT AND COVER YOUR HEAD WITH YOUR HANDS.

&&

LAT...LON 3155 9409 3157 9400 3151 9388 3141 9404
TIME...MOT...LOC 2120Z 311DEG 9KT 3153 9402

$$

06
020 
WWUS54 KSHV 112142
SVSSHV

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SHREVEPORT LA
442 PM CDT WED APR 11 2012

TXC403-405-112152-
/O.EXP.KSHV.TO.W.0034.000000T0000Z-120411T2145Z/
SABINE TX-SAN AUGUSTINE TX-
442 PM CDT WED APR 11 2012

...THE TORNADO WARNING FOR SAN AUGUSTINE AND SABINE COUNTIES WILL
EXPIRE AT 445 PM CDT...

THE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO HAS DECREASED IN 
INTENSITY.

LAT...LON 3155 9409 3157 9400 3151 9388 3141 9404
TIME...MOT...LOC 2142Z 311DEG 9KT 3149 9397

$$

06

The office that day

Everything else NWS Shreveport, LA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 10, 8:17 PM CDTSevere Thunderstorm WarningSHVBowie43 min
Apr 10, 9:40 PM CDTSevere Thunderstorm WarningSHVBowie35 min
Apr 11, 2:50 PM CDTTornado WarningSHVRusk40 min
Apr 11, 3:22 PM CDTTornado WarningSHVRusk31 min
Apr 11, 4:06 PM CDTTornado WarningSHVNacogdoches, Shelby39 min

Nearby

Tornado Warnings in Texas, 2012Every tornado warning in 2012Tornadoes 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.