Alert archive / Oklahoma / Tornado Warnings in 2011

Tornado Warning 76, NWS Norman, OK

September 17, 2011Grant County, Oklahoma

NWS Norman, OK issued this tornado warning at Sep 17, 2011, 5:41 PM CDT for Grant County, Oklahoma. It was in force for 64 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: Sep 17, 2011, 5:41 PM CDT (22:41 UTC)
Expired: Sep 17, 2011, 6:45 PM CDT
In force: 64 min
Issued by: NWS Norman, OK
Area: Storm-based polygon

County Grant County, OK

The radar

The Vance AFB radar (KVNX), 35 km from the middle of the area, began a volume at 22:42 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
Sep 17, 5:57 PM CDT	TORNADO	10 W Medford, OK	TORNADO SPOTTED ONE MILE WEST OF REDHILL ROAD ALONG STATE HIGHWAY 11. GRANT COUNTY SPOTTER REPORT RELAYED BY GARFIELD COUNTY EMERGENCY MANAGER.

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
Sep 17, 2:30 PM CDT	Tornado Watch	SPC	9 hr

The nearest sounding before it

Lamont, OK (KLMN), launched 12:00Z, 10.7 hours before the alert went out and 34 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 668 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 307 m²/s²
0-3 km storm-relative helicity: 327 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.3

Open this sounding in Storm Lab

The text

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

241 
WFUS54 KOUN 172241
TOROUN
OKC053-172345-
/O.NEW.KOUN.TO.W.0076.110917T2241Z-110917T2345Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE NORMAN OK
541 PM CDT SAT SEP 17 2011

THE NATIONAL WEATHER SERVICE IN NORMAN HAS ISSUED A

* TORNADO WARNING FOR...
  CENTRAL GRANT COUNTY IN NORTHERN OKLAHOMA...

* UNTIL 645 PM CDT

* AT 540 PM CDT...NATIONAL WEATHER SERVICE RADAR INDICATED A 
SEVERE   THUNDERSTORM CAPABLE OF PRODUCING A TORNADO MOVING 
EAST-SOUTHEAST AT 20 MPH. THE MOST DANGEROUS PART OF THE STORM WAS 
LOCATED ABOUT 4 MILES SOUTHWEST OF WAKITA.

* LOCATIONS IN THE WARNING INCLUDE JEFFERSON...MEDFORD AND WAKITA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. LEAVE MOBILE HOMES AND VEHICLES. IF POSSIBLE...MOVE
TO A BASEMENT OR STORM SHELTER. OTHERWISE MOVE TO AN INTERIOR ROOM OR
HALLWAY ON THE LOWEST FLOOR. STAY AWAY FROM WINDOWS AND OUTSIDE
WALLS.

&&

LAT...LON 3691 9755 3664 9763 3677 9805 3692 9798
TIME...MOT...LOC 2240Z 278DEG 18KT 3683 9794

$$

1 follow-up statement

171 
WWUS54 KOUN 172306
SVSOUN

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE NORMAN OK
606 PM CDT SAT SEP 17 2011

OKC053-172345-
/O.CON.KOUN.TO.W.0076.000000T0000Z-110917T2345Z/
GRANT OK-
606 PM CDT SAT SEP 17 2011

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 645 PM CDT FOR CENTRAL
GRANT COUNTY...

AT 606 PM CDT...A THUNDERSTORM WITH A HISTORY OF PRODUCING TORNADOES
WAS LOCATED 6 MILES WEST OF MEDFORD...MOVING EAST AT 20 MPH.

* LOCATIONS IN THE WARNING INCLUDE JEFFERSON AND MEDFORD.

LAT...LON 3677 9798 3688 9791 3691 9755 3664 9763
TIME...MOT...LOC 2306Z 278DEG 18KT 3679 9783

$$

The office that day

Everything else NWS Norman, OK issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 17, 5:41 AM CDT	Special Weather Statement	OUN	Alfalfa	34 min
Sep 17, 6:09 AM CDT	Special Weather Statement	OUN	Alfalfa, Grant	36 min
Sep 17, 3:04 PM CDT	Special Weather Statement	OUN	Harper	26 min
Sep 17, 3:25 PM CDT	Severe Thunderstorm Warning	OUN	Harper, Woods, Woodward	65 min
Sep 17, 3:47 PM CDT	Special Weather Statement	OUN	Ellis	13 min
Sep 17, 3:51 PM CDT	Special Weather Statement	OUN	Harmon	24 min
Sep 17, 4:09 PM CDT	Special Weather Statement	OUN	Alfalfa	21 min
Sep 17, 4:18 PM CDT	Severe Thunderstorm Warning	OUN	Beckham, Washita	57 min
Sep 17, 4:21 PM CDT	Severe Thunderstorm Warning	OUN	Alfalfa, Grant	39 min
Sep 17, 4:26 PM CDT	Severe Thunderstorm Warning	OUN	Harper, Woods, Woodward	64 min
Sep 17, 4:37 PM CDT	Special Weather Statement	OUN	Jackson	23 min
Sep 17, 4:42 PM CDT	Severe Thunderstorm Warning	OUN	Woodward	63 min
Sep 17, 4:43 PM CDT	Severe Thunderstorm Warning	OUN	Jackson	62 min
Sep 17, 4:55 PM CDT	Severe Thunderstorm Warning	OUN	Greer, Harmon	11 min
Sep 17, 4:57 PM CDT	Tornado Warning	OUN	Alfalfa, Grant	48 min
Sep 17, 5:22 PM CDT	Severe Thunderstorm Warning	OUN	Alfalfa, Woods	53 min
Sep 17, 5:24 PM CDT	Severe Thunderstorm Warning	OUN	Tillman	66 min
Sep 17, 5:29 PM CDT	Severe Thunderstorm Warning	OUN	Kiowa, Washita	61 min
Sep 17, 5:44 PM CDT	Special Weather Statement	OUN	Kay	31 min
Sep 17, 6:01 PM CDT	Severe Thunderstorm Warning	OUN	Comanche, Cotton, Kiowa, Tillman	59 min
Sep 17, 6:02 PM CDT	Severe Thunderstorm Warning	OUN	Alfalfa, Dewey, Grant, Major, Woods, Woodward	58 min
Sep 17, 6:27 PM CDT	Severe Thunderstorm Warning	OUN	Cotton, Tillman	63 min
Sep 17, 6:35 PM CDT	Severe Thunderstorm Warning	OUN	Grant, Kay	55 min
Sep 17, 6:49 PM CDT	Severe Thunderstorm Warning	OUN	Alfalfa, Garfield, Grant, Major	41 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.