Alert archive / Texas / Tornado Warnings in 2011

Tornado Warning 72, NWS Shreveport, LA

May 20, 2011Harrison County, Marion County, Texas

NWS Shreveport, LA issued this tornado warning at May 20, 2011, 6:38 PM CDT for Harrison County, Marion County, Texas. It was in force for 21 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 20, 2011, 6:38 PM CDT (23:38 UTC)
Expired
May 20, 2011, 6:59 PM CDT
In force
21 min
Issued by
NWS Shreveport, LA
Area
Storm-based polygon

Counties Harrison County, TX, Marion County, TX

The radar

The Shreveport radar (KSHV), 64 km from the middle of the area, began a volume at 23:40 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

TimeReportWhereRemark
May 20, 6:38 PM CDTTORNADO4 Ne Hallsville, TXAN EF0 TORNADO FIRST TOUCHED DOWN NORTHEAST OF HALLSVILLE ALONG YOUNG ROAD JUST NORTH OF OLD HWY. 80. THE STORM THEN CROSSED NOONDAY ROAD SNAPPING AND OR UPROOTING A FEW TREES. THE STORM CROSSED FM. 449 WHERE IT SNAPPED LARGE LIMBS BEFORE LIFTING JUST AS IT CR

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.

IssuedProductOfficeLasted
May 20, 5:56 PM CDTTornado WatchSPC3 hr

The nearest sounding before it

Shreveport, LA (KSHV), launched 12:00Z, 11.6 hours before the alert went out and 71 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 2011-05-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2656 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, Shreveport, LA at 12:00Z on 2011-05-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 151 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
2656 J/kg
Mixed-layer CIN
-44 J/kg
Mixed-layer LCL
648 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
151 m²/s²
0-3 km storm-relative helicity
231 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.

980 
WFUS54 KSHV 202338
TORSHV
TXC203-315-210030-
/O.NEW.KSHV.TO.W.0072.110520T2338Z-110521T0030Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SHREVEPORT LA
638 PM CDT FRI MAY 20 2011

THE NATIONAL WEATHER SERVICE IN SHREVEPORT HAS ISSUED A

* TORNADO WARNING FOR...
  WESTERN HARRISON COUNTY IN NORTHEAST TEXAS...
  SOUTH CENTRAL MARION COUNTY IN NORTHEAST TEXAS...

* UNTIL 730 PM CDT

* AT 636 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED 
A   SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO JUST 
NORTHEAST OF HALLSVILLE...OR 11 MILES WEST OF MARSHALL...MOVING 
NORTHEAST AT 25 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
  HARLETON AND WOODLAWN...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DO NOT USE YOUR CAR TO TRY TO OUTRUN A TORNADO. CARS ARE EASILY
TOSSED AROUND BY TORNADO WINDS. IF YOU ARE CAUGHT IN THE PATH OF A
TORNADO...LEAVE THE CAR AND GO TO A STRONG BUILDING. IF NO SAFE
STRUCTURE IS NEARBY...SEEK SHELTER IN A DITCH OR LOW SPOT AND COVER
YOUR HEAD.

&&

LAT...LON 3279 9449 3265 9421 3242 9455 3255 9469
TIME...MOT...LOC 2338Z 220DEG 21KT 3257 9454

$$

VII
2 follow-up statements
394 
WWUS54 KSHV 202346
SVSSHV

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SHREVEPORT LA
646 PM CDT FRI MAY 20 2011

TXC203-315-210030-
/O.CON.KSHV.TO.W.0072.000000T0000Z-110521T0030Z/
HARRISON TX-MARION TX-
646 PM CDT FRI MAY 20 2011

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 730 PM CDT FOR MARION
AND HARRISON COUNTIES...

AT 645 PM CDT...DOPPLER RADAR CONTINUED TO SHOW STRONG INDICATION
OF A TORNADO JUST NORTHWEST OF NESBITT...MOVING NORTHEAST AT
35 MPH. IF YOU LIVE IN THE NESBITT OR WOODLAWN AREAS...TAKE
COVER IMMEDIATELY. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A TORNADO WARNING MEANS THAT STRONG ROTATION HAS BEEN DETECTED IN THE
STORM. A TORNADO MAY ALREADY BE ON THE GROUND...OR IS EXPECTED TO
DEVELOP SHORTLY. IF YOU ARE IN THE PATH OF THIS DANGEROUS STORM...
MOVE INDOORS AND TO THE LOWEST LEVEL OF THE BUILDING. STAY AWAY FROM
WINDOWS. IF DRIVING...DO NOT SEEK SHELTER UNDER A HIGHWAY OVERPASS.

&&

LAT...LON 3252 9446 3259 9461 3279 9449 3265 9421
TIME...MOT...LOC 2345Z 213DEG 31KT 3262 9447

$$

13
497 
WWUS54 KSHV 202359
SVSSHV

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SHREVEPORT LA
659 PM CDT FRI MAY 20 2011

TXC203-315-210008-
/O.CAN.KSHV.TO.W.0072.000000T0000Z-110521T0030Z/
HARRISON TX-MARION TX-
659 PM CDT FRI MAY 20 2011

...THE TORNADO WARNING FOR MARION AND HARRISON COUNTIES IS
CANCELLED...

ALTHOUGH THIS THUNDERSTORM HAS NOT COMPLETELY DISSIPATED...THERE IS NO 
LONGER EVIDENCE OF ROTATION WITH THIS STORM.

LAT...LON 3252 9446 3259 9461 3279 9449 3265 9421
TIME...MOT...LOC 2358Z 213DEG 31KT 3271 9440

$$

VII

The office that day

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

IssuedProductOfficeCountiesLasted
May 20, 4:58 PM CDTSevere Thunderstorm WarningSHVSmith, Upshur36 min
May 20, 5:02 PM CDTSevere Thunderstorm WarningSHVGregg, Harrison, Rusk43 min
May 20, 5:27 PM CDTTornado WarningSHVRed River48 min
May 20, 5:53 PM CDTSevere Thunderstorm WarningSHVGregg, Harrison, Marion, Rusk52 min
May 20, 6:55 PM CDTSevere Thunderstorm WarningSHVBowie, Red River47 min

Nearby

Tornado Warnings in Texas, 2011Every tornado warning in 2011Tornadoes in 2011

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.