Alert archive / Oklahoma / Tornado Warnings in 2011

Tornado Warning 71, NWS Shreveport, LA

May 20, 2011McCurtain County, Oklahoma

NWS Shreveport, LA issued this tornado warning at May 20, 2011, 5:59 PM CDT for McCurtain County, Oklahoma. It was in force for 21 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: May 20, 2011, 5:59 PM CDT (22:59 UTC)
Expired: May 20, 2011, 6:20 PM CDT
In force: 21 min
Issued by: NWS Shreveport, LA
Area: Storm-based polygon

County McCurtain County, OK

The radar

The Western Arkansas radar (KSRX), 131 km from the middle of the area, began a volume at 22:59 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 watch it was issued in

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

Issued	Product	Office	Lasted
May 20, 11:03 AM CDT	Tornado Watch	SPC	7 hr
May 20, 5:56 PM CDT	Tornado Watch	SPC	3 hr

The nearest sounding before it

Shreveport, LA (KSHV), launched 12:00Z, 11.0 hours before the alert went out and 206 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: 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.

342 
WFUS54 KSHV 202259
TORSHV
OKC089-202345-
/O.NEW.KSHV.TO.W.0071.110520T2259Z-110520T2345Z/

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

THE NATIONAL WEATHER SERVICE IN SHREVEPORT HAS ISSUED A

* TORNADO WARNING FOR...
  CENTRAL MCCURTAIN COUNTY IN SOUTHEAST OKLAHOMA...

* UNTIL 645 PM CDT

* AT 558 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO 16 MILES WEST OF
  BROKEN BOW...OR 23 MILES NORTH OF CLARKSVILLE...MOVING NORTHEAST AT
  35 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
  WRIGHT CITY...GOLDEN...HOLLY CREEK...GLOVER...OAK HILL...
  HOCHATOWN...MOUNT HERMAN AND SHERWOOD.

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 3422 9446 3418 9447 3386 9495 3396 9511
      3446 9475
TIME...MOT...LOC 2258Z 222DEG 32KT 3398 9496

$$

13

1 follow-up statement

265 
WWUS54 KSHV 202320
SVSSHV

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

OKC089-202330-
/O.CAN.KSHV.TO.W.0071.000000T0000Z-110520T2345Z/
MCCURTAIN OK-
620 PM CDT FRI MAY 20 2011

...THE TORNADO WARNING FOR MCCURTAIN COUNTY IS CANCELLED...

THE STORM THAT PROMPTED THE TORNADO WARNING FOR MCCURTAIN COUNTY
HAS WEAKENED AND IS NO LONGER TORNADIC AT THIS TIME. 

LAT...LON 3422 9446 3418 9447 3386 9495 3396 9511
      3446 9475
TIME...MOT...LOC 2320Z 222DEG 32KT 3413 9480

$$

13

The office that day

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

Issued	Product	Office	Counties	Lasted
May 20, 5:27 PM CDT	Tornado Warning	SHV	McCurtain	48 min
May 20, 6:55 PM CDT	Severe Thunderstorm Warning	SHV	McCurtain	47 min

Nearby

Tornado Warnings in Oklahoma, 2011 Every tornado warning in 2011 Tornadoes 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.