Alert archive / Texas / Tornado Warnings in 2012

Tornado Warning 36, NWS Houston/Galveston, TX

August 21, 2012Chambers County, Texas

NWS Houston/Galveston, TX issued this tornado warning at Aug 21, 2012, 5:46 PM CDT for Chambers County, Texas. It was in force for 29 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
Aug 21, 2012, 5:46 PM CDT (22:46 UTC)
Expired
Aug 21, 2012, 6:15 PM CDT
In force
29 min
Issued by
NWS Houston/Galveston, TX
Area
Storm-based polygon

County Chambers County, TX

The radar

The Houston radar (KHGX), 33 km from the middle of the area, began a volume at 22:47 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.

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 10.8 hours before the alert went out and 167 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, Lake Charles Mun, LA at 12:00Z on 2012-08-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 339 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, Lake Charles Mun, LA at 12:00Z on 2012-08-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -4 square meters per square second.193958Sfc1 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
339 J/kg
Mixed-layer CIN
-50 J/kg
Mixed-layer LCL
1015 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
-4 m²/s²
0-3 km storm-relative helicity
22 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

149 
WFUS54 KHGX 212246
TORHGX
TXC071-212315-
/O.NEW.KHGX.TO.W.0036.120821T2246Z-120821T2315Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
546 PM CDT TUE AUG 21 2012

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY  HAS ISSUED A

* TORNADO WARNING FOR...
  EXTREME WEST CENTRAL CHAMBERS COUNTY IN SOUTHEAST TEXAS...

* UNTIL 615 PM CDT

* AT 536 PM CDT...CHAMBERS COUNTY SHERIFF REPORTING A 
  WATERSPOUT JUST OFF THE COAST OF BEACH CITY THAT IS 
  CURRENTLY APPROACHING THE COAST NEAR FM 2354. RESIDENTS IN THE 
  AREA SHOULD TAKE COVER NOW.

* THIS TORNADIC THUNDERSTORM WILL AFFECT THE BEACH CITY AREA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. MOVE TO A BASEMENT OR AN INTERIOR ROOM ON THE
LOWEST FLOOR OF A STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE
HOME OR OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND
PROTECT YOURSELF FROM FLYING DEBRIS.

&&

LAT...LON 2972 9485 2970 9486 2968 9486 2965 9492
      2967 9493 2977 9487 2975 9483
TIME...MOT...LOC 2236Z 271DEG 0KT 2968 9483 

$$
1 follow-up statement
170 
WWUS54 KHGX 212312
SVSHGX

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
612 PM CDT TUE AUG 21 2012

TXC071-212315-
/O.CON.KHGX.TO.W.0036.000000T0000Z-120821T2315Z/
CHAMBERS TX-
612 PM CDT TUE AUG 21 2012

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 615 PM CDT FOR
EXTREME WEST CENTRAL CHAMBERS COUNTY...

AT 600 PM CDT...DOPPLER RADAR CONTINUES TO SHOW A 
THUNDERSTORM SITUATED JUST ALONG THE COAST OF WESTERN 
CHAMBERS COUNTY...GENERALLY ALONG AND SOUTH OF FM 2354. 
RECENT REPORTS INDICATE THE WATERSPOUT MOVED JUST INLAND...AND 
TECHNICALLY BECAME A TORNADO...ALONG THE COAST NEAR BEACH CITY THEN 
LIFTED. NO DAMAGE WAS REPORTED. THIS STORM IS STILL BEING 
MONITORED...BUT THE TORNADO WARNING WILL LIKELY BE ALLOWED TO 
EXPIRE AT 615 PM ASSUMING NO SIGNIFICANT CHANGES ARE NOTED.

LOCATIONS IMPACTED INCLUDE...  
AREAS ALONG FM 2354 IN SOUTHWEST CHAMBERS COUNTY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! MOVE TO A BASEMENT OR AN INTERIOR ROOM ON THE
LOWEST FLOOR OF A STURDY BUILDING. AVOID WINDOWS. IF IN A MOBILE
HOME OR OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND
PROTECT YOURSELF FROM FLYING DEBRIS.

&&

LAT...LON 2968 9487 2965 9492 2967 9492 2967 9493
      2969 9489 2970 9487 2968 9486
TIME...MOT...LOC 2300Z 271DEG 0KT 2968 9483 

$$

The office that day

Everything else NWS Houston/Galveston, TX issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 21, 5:46 PM CDTSpecial Marine WarningHGX38 min
Aug 21, 6:22 PM CDTSpecial Marine WarningHGX36 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.