A nearly stationary upper level low over southern California was the mechanism that caused upper level disturbances to move across West Central Texas.  These upper level disturbances interacted with outflow boundaries, daytime heating, and very unstable air to produce severe weather over the three day period which included large hail, damaging winds and tornadoes.

Tornado in THROCKMORTON, TEXAS
From 08-MAY-15 17:40:00 to 08-MAY-15 17:41:00 (CST-6)
Location: THROCKMORTON
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

The sheriff's office reported a tornado about 1 mile north of Throckmorton.

Tornado in HASKELL, TEXAS
From 08-MAY-15 16:30:00 to 08-MAY-15 16:31:00 (CST-6)
Location: O BRIEN
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

A trained spotter reported a tornado through the Haskell County Sheriff's office about 3.7  miles east of O'Brien.

Hail in CALLAHAN, TEXAS
From 09-MAY-15 15:05:00 to 09-MAY-15 15:10:00 (CST-6)
Location: PUTNAM
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorm Wind in THROCKMORTON, TEXAS
From 09-MAY-15 15:39:00 to 09-MAY-15 15:39:00 (CST-6)
Location: LUSK
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter 4 miles east-southeast of Woodson estimated a thunderstorm wind gust of 60 mph.

Thunderstorm Wind in HASKELL, TEXAS
From 08-MAY-15 16:40:00 to 08-MAY-15 16:40:00 (CST-6)
Location: ROCHESTER
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

The sheriff's Office estimated a wind gust of 70 mph in Rochester.

Thunderstorm Wind in THROCKMORTON, TEXAS
From 08-MAY-15 18:37:00 to 08-MAY-15 18:37:00 (CST-6)
Location: WOODSON
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

The Throckmorton Fire Department/Rescue reported numerous tree limbs down in Woodson.

Thunderstorm Wind in THROCKMORTON, TEXAS
From 08-MAY-15 18:50:00 to 08-MAY-15 18:50:00 (CST-6)
Location: WOODSON
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

The Throckmorton Fire Department/Rescue estimated a thunderstorm wind gust of 60 mph in Elbert.

Hail in THROCKMORTON, TEXAS
From 09-MAY-15 16:14:00 to 09-MAY-15 16:14:00 (CST-6)
Location: WOODSON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in STERLING, TEXAS
From 09-MAY-15 22:57:00 to 09-MAY-15 22:57:00 (CST-6)
Location: STERLING CITY CLD AR
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Hail in TOM GREEN, TEXAS
From 09-MAY-15 23:30:00 to 09-MAY-15 23:35:00 (CST-6)
Location: WATER VLY
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in COKE, TEXAS
From 09-MAY-15 23:41:00 to 09-MAY-15 23:41:00 (CST-6)
Location: EDITH
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

The Fire Department/Rescue reported hail up to the size of quarters on U.S. 87 in extreme southwest Coke County.

Thunderstorm Wind in TOM GREEN, TEXAS
From 10-MAY-15 01:10:00 to 10-MAY-15 01:10:00 (CST-6)
Location: TANKERSLY
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter estimated a thunderstorm wind gust of 60 mph, 4 miles north of Kinckerbocker.

Thunderstorm Wind in CONCHO, TEXAS
From 10-MAY-15 01:45:00 to 10-MAY-15 01:45:00 (CST-6)
Location: PAINT ROCK
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reported numerous tree limbs down throughout Paint Rock. The largest limbs were up to 15 feet in length.

Hail in THROCKMORTON, TEXAS
From 08-MAY-15 18:05:00 to 08-MAY-15 18:10:00 (CST-6)
Location: THROCKMORTON
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in THROCKMORTON, TEXAS
From 08-MAY-15 18:10:00 to 08-MAY-15 18:15:00 (CST-6)
Location: ELBERT
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Thunderstorm Wind in COLEMAN, TEXAS
From 10-MAY-15 02:10:00 to 10-MAY-15 02:10:00 (CST-6)
Location: LEADAY
Magnitude: 60.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: RAWS

A RAWS observation site measured a wind gust of 69 mph, 4 miles west-northwest of Stacy.

Thunderstorm Wind in SHACKELFORD, TEXAS
From 10-MAY-15 03:15:00 to 10-MAY-15 03:15:00 (CST-6)
Location: MORAN
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

A COOP Observer reported numerous tree limbs blown down in Moran, which were up to 8 feet in length.

Hail in KIMBLE, TEXAS
From 10-MAY-15 08:57:00 to 10-MAY-15 08:57:00 (CST-6)
Location: ROOSEVELT
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in SUTTON, TEXAS
From 10-MAY-15 11:04:00 to 10-MAY-15 11:09:00 (CST-6)
Location: SONORA
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

A National Weather Service employee reported golf ball sized hail along Interstate 10 about 15.6 miles east of Sonora.

Hail in THROCKMORTON, TEXAS
From 08-MAY-15 18:50:00 to 08-MAY-15 18:50:00 (CST-6)
Location: WOODSON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Hail in JONES, TEXAS
From 08-MAY-15 19:55:00 to 08-MAY-15 19:55:00 (CST-6)
Location: ABILENE
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Hail in SHACKELFORD, TEXAS
From 08-MAY-15 21:23:00 to 08-MAY-15 21:23:00 (CST-6)
Location: ALBANY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in THROCKMORTON, TEXAS
From 09-MAY-15 14:35:00 to 09-MAY-15 14:40:00 (CST-6)
Location: THROCKMORTON
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Thunderstorm Wind in HASKELL, TEXAS
From 08-MAY-15 16:30:00 to 08-MAY-15 16:30:00 (CST-6)
Location: ROCHESTER
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

The Haskell County Sheriff's Office reported a wind gust of 60 mph in Rochester.

Tornado in THROCKMORTON, TEXAS
From 08-MAY-15 17:22:00 to 08-MAY-15 17:23:00 (CST-6)
Location: THROCKMORTON
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

The public reported a tornado about 13 miles northwest of Throckmorton.

Thunderstorm Wind in COLEMAN, TEXAS
From 10-MAY-15 02:22:00 to 10-MAY-15 02:22:00 (CST-6)
Location: VALERA
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

The Coleman County Fire Department/Rescue estimated a thunderstorm wind gust of 70 mph on U.S. 67 between Valera and Talpa.

Hail in THROCKMORTON, TEXAS
From 09-MAY-15 15:34:00 to 09-MAY-15 15:34:00 (CST-6)
Location: WOODSON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter