A strong warm front became stationary along the interstate 44 corridor during the early afternoon of the 17th. Through the day, areas south of the warm front and east of a well-defined dryline became very unstable. As a large upper trough shifted into the Southern Plains, scattered thunderstorms developed near the dryline/warm front triple point. As these storms moved eastward into the highly unstable warm sector, they became supercellular. These storms produced all facets of severe weather, including very large hail, damaging straight line winds, and a few brief tornadoes. Training of supercells also led to flash flooding over portions of southwest Oklahoma around the Wichita Mountains Wildlife Refuge. Storms eventually shifted eastward and weakened overnight as a cold front pushed through Oklahoma.

Thunderstorm Wind in COMANCHE, OKLAHOMA
From 17-APR-13 19:05:00 to 17-APR-13 19:05:00 (CST-6)
Location: ELGIN
Magnitude: 61.00 EG
Reported by: Amateur Radio

No damage was reported.

Hail in COMANCHE, OKLAHOMA
From 17-APR-13 19:05:00 to 17-APR-13 19:05:00 (CST-6)
Location: ELGIN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in TILLMAN, OKLAHOMA
From 17-APR-13 19:18:00 to 17-APR-13 19:18:00 (CST-6)
Location: DAVIDSON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in COMANCHE, OKLAHOMA
From 17-APR-13 17:33:00 to 17-APR-13 17:33:00 (CST-6)
Location: CACHE
Magnitude: 1.75 
Reported by: Storm Chaser

Hail in KIOWA, OKLAHOMA
From 17-APR-13 17:36:00 to 17-APR-13 17:36:00 (CST-6)
Location: SNYDER
Magnitude: 2.00 
Reported by: Storm Chaser

Thunderstorm Wind in TILLMAN, OKLAHOMA
From 17-APR-13 16:46:00 to 17-APR-13 16:46:00 (CST-6)
Location: FREDERICK
Magnitude: 59.00 MG
Reported by: Trained Spotter

Winds were generated by the rear flank downdraft of a supercell thunderstorm.

Hail in OKLAHOMA, OKLAHOMA
From 17-APR-13 19:20:00 to 17-APR-13 19:20:00 (CST-6)
Location: (TIK)TINKER AFB
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorm Wind in CADDO, OKLAHOMA
From 17-APR-13 17:25:00 to 17-APR-13 17:25:00 (CST-6)
Location: CYRIL
Magnitude: 52.00 MG
Reported by: Amateur Radio

No damage was reported.

Hail in CLEVELAND, OKLAHOMA
From 17-APR-13 19:00:00 to 17-APR-13 19:00:00 (CST-6)
Location: (OUN)NORMAN WESTHEIMER ARPT
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

Thunderstorm Wind in GRADY, OKLAHOMA
From 17-APR-13 19:35:00 to 17-APR-13 19:35:00 (CST-6)
Location: NORGE
Magnitude: 52.00 EG
Reported by: Amateur Radio

No damage was reported.

Thunderstorm Wind in GRADY, OKLAHOMA
From 17-APR-13 19:35:00 to 17-APR-13 19:35:00 (CST-6)
Location: ACME
Magnitude: 53.00 MG
Reported by: Mesonet

Thunderstorm Wind in TILLMAN, OKLAHOMA
From 17-APR-13 19:35:00 to 17-APR-13 19:35:00 (CST-6)
Location: GRANDFIELD
Magnitude: 52.00 EG
Reported by: Amateur Radio

No damage was reported.

Thunderstorm Wind in OKLAHOMA, OKLAHOMA
From 17-APR-13 19:37:00 to 17-APR-13 19:37:00 (CST-6)
Location: (TIK)TINKER AFB
Magnitude: 52.00 EG
Reported by: NWS Employee

No damage was reported.

Thunderstorm Wind in TILLMAN, OKLAHOMA
From 17-APR-13 19:45:00 to 17-APR-13 19:45:00 (CST-6)
Location: GRANDFIELD
Magnitude: 63.00 MG
Reported by: Mesonet

Thunderstorm Wind in TILLMAN, OKLAHOMA
From 17-APR-13 19:50:00 to 17-APR-13 19:50:00 (CST-6)
Location: GRANDFIELD
Magnitude: 56.00 MG
Reported by: Mesonet

Hail in TILLMAN, OKLAHOMA
From 17-APR-13 19:50:00 to 17-APR-13 19:50:00 (CST-6)
Location: GRANDFIELD
Magnitude: 2.00 
Reported by: NWS Employee

No damage was reported.

Hail in GRADY, OKLAHOMA
From 17-APR-13 19:52:00 to 17-APR-13 19:52:00 (CST-6)
Location: RUSH SPRINGS
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in GRADY, OKLAHOMA
From 17-APR-13 19:53:00 to 17-APR-13 19:53:00 (CST-6)
Location: RUSH SPRINGS
Magnitude: 2.50 
Reported by: Amateur Radio

No damage was reported.

Hail in GRADY, OKLAHOMA
From 17-APR-13 20:01:00 to 17-APR-13 20:01:00 (CST-6)
Location: AGAWAM
Magnitude: 1.75 
Reported by: Storm Chaser

No damage was reported.

Hail in COTTON, OKLAHOMA
From 17-APR-13 20:18:00 to 17-APR-13 20:18:00 (CST-6)
Location: COOKIETOWN
Magnitude: 1.25 
Reported by: Trained Spotter

No damage was reported.

Flash Flood in TILLMAN, OKLAHOMA
From 17-APR-13 19:45:00 to 17-APR-13 19:45:00 (CST-6)
Location: GRANDFIELD
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Training supercells lead to flash flooding in creeks and low lying areas over rural Tillman county. No major damage was reported and no injuries or fatalities occurred.

Flash Flood in COMANCHE, OKLAHOMA
From 17-APR-13 19:50:00 to 17-APR-13 22:50:00 (CST-6)
Location: (FSI)FORT SILL
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Training supercells lead to heavy rainfall and flash flooding north of Lawton. No major damage was reported and no injuries or fatalities occurred.

Flash Flood in MCCLAIN, OKLAHOMA
From 17-APR-13 19:53:00 to 17-APR-13 22:53:00 (CST-6)
Location: NEWCASTLE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Persistent heavy rainfall from training supercell thunderstorms led to localized flash flooding in the Newcastle area. No major damage was reported and no injuries or fatalities occurred.

Flash Flood in GRADY, OKLAHOMA
From 17-APR-13 19:55:00 to 17-APR-13 22:55:00 (CST-6)
Location: CHICKASHA ARPT
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Persistent heavy rainfall led to widespread flash flooding across Chickasha. No major damage was reported and no injuries or fatalities occurred.

Flash Flood in POTTAWATOMIE, OKLAHOMA
From 17-APR-13 21:46:00 to 17-APR-13 21:46:00 (CST-6)
Location: SHAWNEE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy rainfall from several rounds of thunderstorms led to flooding in downtown Shawnee. Numerous streets were in curb deep water. No major damage was reported and no injuries or fatalities occurred.

Hail in WASHITA, OKLAHOMA
From 17-APR-13 14:28:00 to 17-APR-13 14:28:00 (CST-6)
Location: COWDEN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in COTTON, OKLAHOMA
From 17-APR-13 20:26:00 to 17-APR-13 20:26:00 (CST-6)
Location: WALTERS ARPT
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in COTTON, OKLAHOMA
From 17-APR-13 20:29:00 to 17-APR-13 20:29:00 (CST-6)
Location: WALTERS
Magnitude: 1.75 
Reported by: Trained Spotter

No damage was reported.

Hail in LINCOLN, OKLAHOMA
From 17-APR-13 21:09:00 to 17-APR-13 21:09:00 (CST-6)
Location: SPARKS
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in STEPHENS, OKLAHOMA
From 17-APR-13 21:30:00 to 17-APR-13 21:30:00 (CST-6)
Location: DUNCAN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Tornado in TILLMAN, OKLAHOMA
From 17-APR-13 19:35:00 to 17-APR-13 19:45:00 (CST-6)
Location: GRANDFIELD
Tornado F-scale: EF1
Property damage: 500.00K
Reported by: Trained Spotter

Multiple spotter and storm chaser reports of a tornado. Damage occurred a the Grandfield airport. The tornado has been assigned a preliminary EF-1 rating.

Tornado in COMANCHE, OKLAHOMA
From 17-APR-13 17:50:00 to 17-APR-13 17:56:00 (CST-6)
Location: CACHE
Tornado F-scale: EF0
Property damage: 200.00K
Crop damage: 0.00K
Reported by: NWS Employee

The tornado was reported on the west side of Lawton. Minor damage was done to the Goodyear Tire Plant at southwest Lee and Goodyear Boulevards.

Hail in TILLMAN, OKLAHOMA
From 17-APR-13 14:42:00 to 17-APR-13 14:42:00 (CST-6)
Location: TIPTON ARPT
Magnitude: 1.50 
Reported by: Amateur Radio

No damage was reported.

Hail in HARMON, OKLAHOMA
From 17-APR-13 16:12:00 to 17-APR-13 16:12:00 (CST-6)
Location: GOULD
Magnitude: 1.25 
Reported by: COOP Observer

No damage was reported.

Thunderstorm Wind in TILLMAN, OKLAHOMA
From 17-APR-13 19:37:00 to 17-APR-13 19:37:00 (CST-6)
Location: LOVELAND
Magnitude: 69.00 MG
Reported by: Storm Chaser

No damage was reported.

Hail in TILLMAN, OKLAHOMA
From 17-APR-13 15:10:00 to 17-APR-13 15:10:00 (CST-6)
Location: MANITOU
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in COMANCHE, OKLAHOMA
From 17-APR-13 16:15:00 to 17-APR-13 16:15:00 (CST-6)
Location: CACHE
Magnitude: 1.75 
Reported by: Amateur Radio

No damage was reported.

Hail in GRADY, OKLAHOMA
From 17-APR-13 20:25:00 to 17-APR-13 20:25:00 (CST-6)
Location: ALEX
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Post Office

Hail in TILLMAN, OKLAHOMA
From 17-APR-13 14:38:00 to 17-APR-13 14:38:00 (CST-6)
Location: FREDERICK
Magnitude: 1.25 
Reported by: Storm Chaser

No damage was reported.

Hail in MCCLAIN, OKLAHOMA
From 17-APR-13 21:12:00 to 17-APR-13 21:12:00 (CST-6)
Location: PURCELL
Magnitude: 1.50 
Reported by: Trained Spotter

No damage was reported.

Hail in GARVIN, OKLAHOMA
From 17-APR-13 22:05:00 to 17-APR-13 22:05:00 (CST-6)
Location: LINDSAY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Post Office

Hail in COMANCHE, OKLAHOMA
From 17-APR-13 16:26:00 to 17-APR-13 16:26:00 (CST-6)
Location: FAXON
Magnitude: 1.75 
Reported by: Storm Chaser

No damage was reported.

Hail in CANADIAN, OKLAHOMA
From 17-APR-13 16:25:00 to 17-APR-13 16:25:00 (CST-6)
Location: RICHLAND
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in COMANCHE, OKLAHOMA
From 17-APR-13 16:30:00 to 17-APR-13 16:30:00 (CST-6)
Location: MT SCOTT
Magnitude: 1.75 
Reported by: Amateur Radio

No damage was reported.

Thunderstorm Wind in CLEVELAND, OKLAHOMA
From 17-APR-13 22:39:00 to 17-APR-13 22:39:00 (CST-6)
Location: LEXINGTON
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

No damage was reported.

Hail in COMANCHE, OKLAHOMA
From 17-APR-13 16:46:00 to 17-APR-13 16:46:00 (CST-6)
Location: ELGIN
Magnitude: 1.75 
Reported by: Amateur Radio

No damage was reported.

Hail in JACKSON, OKLAHOMA
From 17-APR-13 16:49:00 to 17-APR-13 16:49:00 (CST-6)
Location: ELMER
Magnitude: 1.75 
Reported by: Amateur Radio

Hail in BECKHAM, OKLAHOMA
From 17-APR-13 16:59:00 to 17-APR-13 16:59:00 (CST-6)
Location: ELK CITY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CADDO, OKLAHOMA
From 17-APR-13 17:24:00 to 17-APR-13 17:24:00 (CST-6)
Location: CYRIL
Magnitude: 1.25 
Reported by: Amateur Radio

Hail in COMANCHE, OKLAHOMA
From 17-APR-13 17:29:00 to 17-APR-13 17:29:00 (CST-6)
Location: CACHE
Magnitude: 2.75 
Reported by: Trained Spotter

No damage was reported.

Hail in KIOWA, OKLAHOMA
From 17-APR-13 17:35:00 to 17-APR-13 17:35:00 (CST-6)
Location: SNYDER
Magnitude: 1.75 
Reported by: Amateur Radio

Hail in CADDO, OKLAHOMA
From 17-APR-13 18:45:00 to 17-APR-13 18:45:00 (CST-6)
Location: CYRIL
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in GRADY, OKLAHOMA
From 17-APR-13 18:16:00 to 17-APR-13 18:16:00 (CST-6)
Location: TABLER
Magnitude: 1.75 
Reported by: Amateur Radio

Hail in COMANCHE, OKLAHOMA
From 17-APR-13 18:16:00 to 17-APR-13 18:16:00 (CST-6)
Location: ELGIN
Magnitude: 1.75 
Reported by: Amateur Radio

Hail in COMANCHE, OKLAHOMA
From 17-APR-13 18:32:00 to 17-APR-13 18:32:00 (CST-6)
Location: ELGIN
Magnitude: 1.25 
Reported by: Amateur Radio

Hail in COMANCHE, OKLAHOMA
From 17-APR-13 17:31:00 to 17-APR-13 17:31:00 (CST-6)
Location: CACHE
Magnitude: 2.25 
Reported by: Storm Chaser

No damage was reported.

Hail in COMANCHE, OKLAHOMA
From 17-APR-13 17:31:00 to 17-APR-13 17:31:00 (CST-6)
Location: CACHE
Magnitude: 1.75 
Reported by: Storm Chaser

Hail in KIOWA, OKLAHOMA
From 17-APR-13 17:33:00 to 17-APR-13 17:33:00 (CST-6)
Location: SNYDER
Magnitude: 2.00 
Reported by: Storm Chaser

Hail in COMANCHE, OKLAHOMA
From 17-APR-13 19:09:00 to 17-APR-13 19:09:00 (CST-6)
Location: FLETCHER
Magnitude: 1.25 
Reported by: Storm Chaser

No damage was reported.

Hail in WASHITA, OKLAHOMA
From 17-APR-13 14:15:00 to 17-APR-13 14:15:00 (CST-6)
Location: CLOUD CHIEF
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public