A severe weather event began during the early afternoon hours of Friday, April 13, 2012, and lasted through the early morning hours of Saturday, April 14, 2012. Around a dozen tornadoes, as well as large hail, and strong wind gusts were produced by the numerous thunderstorms that occurred during this event. Much of the severe weather occurred in parts of southwestern and central Oklahoma. However, thunderstorms did develop in other portions of Oklahoma as well during the event.
A moist airmass had been in place over much of the region for several days prior to April 13th, and several rounds of showers and thunderstorms had occurred during this period. On Friday, April 13th, a dryline and weak frontal boundary moved into the area extending from near southwestern and west central Oklahoma then northeast into north central Oklahoma by the early afternoon hours. The first storms developed in parts of southwestern Oklahoma and west Texas. However, it was several hours before the first tornado occurred. In fact, the potential for tornadoes increased during the early evening hours of April 13th as the low level jet (strong winds just above the surface) became stronger.
The first tornadic activity of the day occurred in central Oklahoma as a tornado touched down just southwest of Norman at 3:59 pm CDT, and then moved east-northeast through the heart of that city shortly after 4:00 pm CDT. This tornado was eventually rated an EF-1 as it damaged many businesses and homes, and numerous trees and power lines were also downed. No fatalities were reported with this rush hour tornado, but 20 injuries were reported. The same parent supercell thunderstorm that produced the Norman tornado also spawned a brief, weak tornado in Pottawatomie County 6 miles northwest of Shawnee, OK.
Meanwhile, supercell thunderstorms continued to develop in southwestern Oklahoma. Nine tornadoes occurred in this area with 3, and possibly 4 tornadoes occurring at one time with a storm near Cooperton, OK in Kiowa County during the evening of April 13th. Two tornadoes were also reported near Blair, OK in Jackson County, and 3 tornadoes were observed near Carnegie, OK in Caddo County.
Large hail and strong wind gusts was also reported with these severe thunderstorms. The largest hail reported was 3 inches in diameter and fell in an area 12 miles south of Sayre, OK. Several wind gusts to 70 mph were also reported.
Approximately 12 tornadoes occurred during this severe weather event. Fortunately, no fatalities or major injuries were reported with these tornadoes.

Hail in CADDO, OKLAHOMA
From 13-APR-12 14:25:00 to 13-APR-12 14:25:00 (CST-6)
Location: FT COBB
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in KIOWA, OKLAHOMA
From 13-APR-12 14:22:00 to 13-APR-12 14:22:00 (CST-6)
Location: ROOSEVELT
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Thunderstorm Wind in JACKSON, OKLAHOMA
From 13-APR-12 17:33:00 to 13-APR-12 17:33:00 (CST-6)
Location: BLAIR
Magnitude: 61.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in KIOWA, OKLAHOMA
From 13-APR-12 13:49:00 to 13-APR-12 13:49:00 (CST-6)
Location: ROOSEVELT
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in JACKSON, OKLAHOMA
From 13-APR-12 17:21:00 to 13-APR-12 17:21:00 (CST-6)
Location: BLAIR
Magnitude: 61.00 EG
Reported by: Amateur Radio

A large grain silo was destroyed. Multiple power lines were downed. Large trees were snapped. A wooden shed was destroyed with debris scattered into the roadway. Multiple houses sustained roof damage of varying degrees. The winds were result of the rear-flank downdraft associated with a supercell moving east of town.

Hail in KIOWA, OKLAHOMA
From 13-APR-12 17:55:00 to 13-APR-12 17:55:00 (CST-6)
Location: ROOSEVELT
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Thunderstorm Wind in JACKSON, OKLAHOMA
From 13-APR-12 17:30:00 to 13-APR-12 17:30:00 (CST-6)
Location: (LTS)ALTUS AFB
Magnitude: 61.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CADDO, OKLAHOMA
From 13-APR-12 12:55:00 to 13-APR-12 12:55:00 (CST-6)
Location: CYRIL
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in JACKSON, OKLAHOMA
From 13-APR-12 16:05:00 to 13-APR-12 16:05:00 (CST-6)
Location: BLAIR
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in JACKSON, OKLAHOMA
From 13-APR-12 17:22:00 to 13-APR-12 17:22:00 (CST-6)
Location: BLAIR
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in CADDO, OKLAHOMA
From 13-APR-12 13:04:00 to 13-APR-12 13:04:00 (CST-6)
Location: ANADARKO
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in JACKSON, OKLAHOMA
From 13-APR-12 13:16:00 to 13-APR-12 13:16:00 (CST-6)
Location: MARTHA
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in CADDO, OKLAHOMA
From 13-APR-12 13:15:00 to 13-APR-12 13:15:00 (CST-6)
Location: ANADARKO
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in HARMON, OKLAHOMA
From 13-APR-12 16:29:00 to 13-APR-12 16:29:00 (CST-6)
Location: HOLLIS
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Hail in COMANCHE, OKLAHOMA
From 13-APR-12 14:00:00 to 13-APR-12 14:00:00 (CST-6)
Location: LAWTON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in OKLAHOMA, OKLAHOMA
From 13-APR-12 15:42:00 to 13-APR-12 15:42:00 (CST-6)
Location: CHOCTAW
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in CUSTER, OKLAHOMA
From 13-APR-12 22:22:00 to 13-APR-12 22:22:00 (CST-6)
Location: STAFFORD
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in WASHITA, OKLAHOMA
From 13-APR-12 22:22:00 to 13-APR-12 22:22:00 (CST-6)
Location: CLOUD CHIEF
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

The hail was reported 8 miles west of Cowden.

Hail in CLEVELAND, OKLAHOMA
From 13-APR-12 15:05:00 to 13-APR-12 15:05:00 (CST-6)
Location: NORMAN
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in GRADY, OKLAHOMA
From 13-APR-12 14:15:00 to 13-APR-12 14:15:00 (CST-6)
Location: AMBER
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in GREER, OKLAHOMA
From 13-APR-12 16:37:00 to 13-APR-12 16:37:00 (CST-6)
Location: MANGUM
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in COMANCHE, OKLAHOMA
From 13-APR-12 13:50:00 to 13-APR-12 13:50:00 (CST-6)
Location: LAWTON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

Hail in KIOWA, OKLAHOMA
From 13-APR-12 13:22:00 to 13-APR-12 13:22:00 (CST-6)
Location: ROOSEVELT
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Tornado in CLEVELAND, OKLAHOMA
From 13-APR-12 15:00:00 to 13-APR-12 15:12:00 (CST-6)
Location: NORMAN
Tornado F-scale: EF1
Reported by: NWS Storm Survey

This tornado moved across the Canadian River into Cleveland County and southwest Norman. The tornado moved east-northeast through the heart of Norman. Numerous trees and power lines were blown down. Minor roof damage was also reported at a number of locations along the path. The higher degree of damage occurred near I-35, and also between Lahoma and Peters Avenues north of Main Street. The tornado finally dissipated just south of NE 12th and Robinson Street.

Tornado in MCCLAIN, OKLAHOMA
From 13-APR-12 14:59:00 to 13-APR-12 15:00:00 (CST-6)
Location: GOLDSBY
Tornado F-scale: EF0
Reported by: NWS Storm Survey

This tornado developed just west of the Canadian River, with minor tree damage reported. The tornado continued into Cleveland county.

Tornado in JACKSON, OKLAHOMA
From 13-APR-12 17:14:00 to 13-APR-12 17:16:00 (CST-6)
Location: BLAIR
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Storm chasers reported another brief tornado southeast of Blair. This tornado produced no known damage.

Tornado in JACKSON, OKLAHOMA
From 13-APR-12 17:10:00 to 13-APR-12 17:12:00 (CST-6)
Location: BLAIR
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Storm chasers reported a brief tornado southeast of Blair. No damage is known to have occurred.

Tornado in KIOWA, OKLAHOMA
From 13-APR-12 18:27:00 to 13-APR-12 18:27:00 (CST-6)
Location: COOPERTON
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

This tornado occurred simultaneously to the end of another tornado south of Cooperton. This tornado produced no known damage and the location is estimated.

Tornado in KIOWA, OKLAHOMA
From 13-APR-12 18:25:00 to 13-APR-12 18:27:00 (CST-6)
Location: COOPERTON
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

An off-duty NWS employee observed this tornado just southeast of Cooperton for a couple of minutes but is not known to have produced any damage. The specific location is estimated.

Tornado in KIOWA, OKLAHOMA
From 13-APR-12 18:28:00 to 13-APR-12 18:33:00 (CST-6)
Location: COOPERTON
Tornado F-scale: EF1
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

Just after the dissipation of two other tornadoes near Cooperton, storm chasers reported a third tornado developed about 2 miles southwest of Cooperton. This large tornado initially moved southeast before crossing state highway 54, then turned northeast. Some damage occurred to a roof and a silo.

Tornado in KIOWA, OKLAHOMA
From 13-APR-12 18:52:00 to 13-APR-12 19:12:00 (CST-6)
Location: COOPERTON
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

A large tornado developed east-northeast of Cooperton and moved north-northeast. Despite the large width, no damage was reported with this tornado and the specific location is estimated.

Tornado in CADDO, OKLAHOMA
From 13-APR-12 19:36:00 to 13-APR-12 19:38:00 (CST-6)
Location: CARNEGIE
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

A tornado was observed south of Carnegie and east of state highway 58. The tornado produced no known damage and the location is estimated.

Tornado in CADDO, OKLAHOMA
From 13-APR-12 19:42:00 to 13-APR-12 19:42:00 (CST-6)
Location: CARNEGIE
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

This tornado formed a few miles south of the initial tornado south of Carnegie. No damage is known to have occurred with this brief tornado.

Tornado in CADDO, OKLAHOMA
From 13-APR-12 19:50:00 to 13-APR-12 19:55:00 (CST-6)
Location: CARNEGIE
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

A third tornado developed south-southeast of Carnegie. This tornado also produced no known damage.

Tornado in POTTAWATOMIE, OKLAHOMA
From 13-APR-12 16:24:00 to 13-APR-12 16:24:00 (CST-6)
Location: DALE
Tornado F-scale: EF0
Reported by: Emergency Manager

This brief tornado developed just northeast of the intersection of Interstate 35 and state highway 270. A small outbuilding was damaged.

Tornado in CANADIAN, OKLAHOMA
From 13-APR-12 23:52:00 to 13-APR-12 23:55:00 (CST-6)
Location: MUSTANG
Tornado F-scale: EF1
Reported by: NWS Storm Survey

The tornado occurred in southwest Oklahoma City, developing just southwest of Southwest 54th Street and Mustang Road and moving north-northwest to near Southwest 29th Street and Tucson Drive (just east of Czech Hall Road). Major roof damage was reported to a structure and four mobile homes sustained minor damage. Several trees, power lines, and fences were blown down along its path, including near the City baseball park.

Tornado in JACKSON, OKLAHOMA
From 13-APR-12 17:30:00 to 13-APR-12 17:35:00 (CST-6)
Location: BLAIR
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Storm chasers reported a tornado east of Blair and just south of state highway 19. The tornado produced no known damage.

Hail in MCCLAIN, OKLAHOMA
From 13-APR-12 14:41:00 to 13-APR-12 14:41:00 (CST-6)
Location: NEWCASTLE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorm Wind in KIOWA, OKLAHOMA
From 13-APR-12 18:35:00 to 13-APR-12 18:35:00 (CST-6)
Location: COOPERTON
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

No damage occurred with the wind gust.

Hail in KIOWA, OKLAHOMA
From 13-APR-12 18:48:00 to 13-APR-12 18:48:00 (CST-6)
Location: LONE WOLF
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in BECKHAM, OKLAHOMA
From 13-APR-12 20:40:00 to 13-APR-12 20:40:00 (CST-6)
Location: DELHI
Magnitude: 3.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in BECKHAM, OKLAHOMA
From 13-APR-12 20:53:00 to 13-APR-12 20:53:00 (CST-6)
Location: CARTER
Magnitude: 2.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

The hail was reported in Moravia.

Hail in CADDO, OKLAHOMA
From 13-APR-12 21:08:00 to 13-APR-12 21:08:00 (CST-6)
Location: ANADARKO
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

The hail was reported on Highway 8.

Hail in CADDO, OKLAHOMA
From 13-APR-12 21:16:00 to 13-APR-12 21:16:00 (CST-6)
Location: ANADARKO
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in CADDO, OKLAHOMA
From 13-APR-12 21:28:00 to 13-APR-12 21:28:00 (CST-6)
Location: ANADARKO
Magnitude: 2.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

The hail was reported near the airport.

Hail in WASHITA, OKLAHOMA
From 13-APR-12 21:39:00 to 13-APR-12 21:39:00 (CST-6)
Location: ROCKY
Magnitude: 2.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in GRADY, OKLAHOMA
From 13-APR-12 21:45:00 to 13-APR-12 21:45:00 (CST-6)
Location: CHICKASHA ARPT
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in CADDO, OKLAHOMA
From 13-APR-12 22:48:00 to 13-APR-12 22:48:00 (CST-6)
Location: EAKLY
Magnitude: 2.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

The hail fell 6 miles northeast of Cowden.

Thunderstorm Wind in CADDO, OKLAHOMA
From 13-APR-12 22:48:00 to 13-APR-12 22:48:00 (CST-6)
Location: EAKLY
Magnitude: 60.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CUSTER, OKLAHOMA
From 13-APR-12 23:10:00 to 13-APR-12 23:10:00 (CST-6)
Location: WEATHERFORD
Magnitude: 2.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in CUSTER, OKLAHOMA
From 13-APR-12 23:10:00 to 13-APR-12 23:10:00 (CST-6)
Location: WEATHERFORD
Magnitude: 61.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CADDO, OKLAHOMA
From 13-APR-12 23:42:00 to 13-APR-12 23:42:00 (CST-6)
Location: HINTON
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

The hail was reported near Highways 281 and 37.

Hail in OKLAHOMA, OKLAHOMA
From 13-APR-12 15:30:00 to 13-APR-12 15:30:00 (CST-6)
Location: CHOCTAW
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in JACKSON, OKLAHOMA
From 13-APR-12 17:16:00 to 13-APR-12 17:16:00 (CST-6)
Location: BLAIR
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in CLEVELAND, OKLAHOMA
From 13-APR-12 14:55:00 to 13-APR-12 14:55:00 (CST-6)
Location: NORMAN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Hail in GRADY, OKLAHOMA
From 13-APR-12 15:53:00 to 13-APR-12 15:53:00 (CST-6)
Location: CHICKASHA ARPT
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in CADDO, OKLAHOMA
From 13-APR-12 13:22:00 to 13-APR-12 13:22:00 (CST-6)
Location: ANADARKO
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Hail in JACKSON, OKLAHOMA
From 13-APR-12 13:26:00 to 13-APR-12 13:26:00 (CST-6)
Location: BLAIR
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in COMANCHE, OKLAHOMA
From 13-APR-12 14:42:00 to 13-APR-12 14:42:00 (CST-6)
Location: MEERS
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

The hail was reported 3 miles north of Lake Lawtonka.

Hail in KIOWA, OKLAHOMA
From 13-APR-12 14:44:00 to 13-APR-12 14:44:00 (CST-6)
Location: COOPERTON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in CADDO, OKLAHOMA
From 13-APR-12 15:06:00 to 13-APR-12 15:06:00 (CST-6)
Location: APACHE
Magnitude: 2.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in KIOWA, OKLAHOMA
From 13-APR-12 15:28:00 to 13-APR-12 15:28:00 (CST-6)
Location: LONE WOLF
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in CLEVELAND, OKLAHOMA
From 13-APR-12 15:30:00 to 13-APR-12 15:30:00 (CST-6)
Location: NORMAN
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

The hail was reported at the ktlx WSR-88D.

Hail in GREER, OKLAHOMA
From 13-APR-12 16:18:00 to 13-APR-12 16:18:00 (CST-6)
Location: GRANITE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in HARMON, OKLAHOMA
From 13-APR-12 16:15:00 to 13-APR-12 16:15:00 (CST-6)
Location: HOLLIS
Magnitude: 2.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in KIOWA, OKLAHOMA
From 13-APR-12 18:13:00 to 13-APR-12 18:13:00 (CST-6)
Location: ROOSEVELT
Magnitude: 2.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter