Tornado Watch number 290 and Severe Thunderstorm Watch number 291 were in effect during this event.
Strong afternoon destabilization occurred north and east of an area of low pressure situated over southwest North Dakota May 22nd. The trigger for thunderstorm development was a strong upper level jet streak advecting northeast across the Rockies and into the Northern Plains. While a strong capping inversion was in place in the low's warm sector, a weaker cap existed over northern North Dakota, where convection first initiated late in the afternoon over the far northwest. Additional strong to severe thunderstorms developed during the evening across the north central and from the south central into the James River Basin. Severe hail, severe thunderstorm winds, and two confirmed EF0 tornadoes occurred during this event.

Hail in STUTSMAN, NORTH DAKOTA
From 22-MAY-12 20:15:00 to 22-MAY-12 20:25:00 (CST-6)
Location: BUCHANAN
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in LA MOURE, NORTH DAKOTA
From 22-MAY-12 20:46:00 to 22-MAY-12 20:48:00 (CST-6)
Location: NORTONVILLE
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in STUTSMAN, NORTH DAKOTA
From 22-MAY-12 21:05:00 to 22-MAY-12 21:09:00 (CST-6)
Location: JAMESTOWN
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in STUTSMAN, NORTH DAKOTA
From 22-MAY-12 21:07:00 to 22-MAY-12 21:11:00 (CST-6)
Location: JAMESTOWN
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in STUTSMAN, NORTH DAKOTA
From 22-MAY-12 20:00:00 to 22-MAY-12 20:07:00 (CST-6)
Location: SYDNEY
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

The trained spotter reported no damage.

Hail in WARD, NORTH DAKOTA
From 22-MAY-12 17:24:00 to 22-MAY-12 17:24:00 (CST-6)
Location: DONNYBROOK
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in STUTSMAN, NORTH DAKOTA
From 22-MAY-12 20:07:00 to 22-MAY-12 20:12:00 (CST-6)
Location: (JMS)JAMESTOWN MUNI
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Large hail accompanied the strong winds.

Hail in WARD, NORTH DAKOTA
From 22-MAY-12 17:35:00 to 22-MAY-12 17:38:00 (CST-6)
Location: DONNYBROOK
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in STUTSMAN, NORTH DAKOTA
From 22-MAY-12 20:10:00 to 22-MAY-12 20:15:00 (CST-6)
Location: BUCHANAN
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

The strong winds broke small tree branches.

Hail in STUTSMAN, NORTH DAKOTA
From 22-MAY-12 19:29:00 to 22-MAY-12 19:33:00 (CST-6)
Location: STREETER
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in MCINTOSH, NORTH DAKOTA
From 22-MAY-12 19:34:00 to 22-MAY-12 19:39:00 (CST-6)
Location: WISHEK
Magnitude: 2.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in STUTSMAN, NORTH DAKOTA
From 22-MAY-12 19:55:00 to 22-MAY-12 19:59:00 (CST-6)
Location: WINDSOR
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Thunderstorm Wind in DIVIDE, NORTH DAKOTA
From 22-MAY-12 15:55:00 to 22-MAY-12 15:59:00 (CST-6)
Location: FORTUNA
Magnitude: 60.00 EG
Property damage: 8.00K
Crop damage: 0.00K
Reported by: Trained Spotter

This storm report stated that tree branches up to six inches in diameter were broken off by the strong winds.

Tornado in DIVIDE, NORTH DAKOTA
From 22-MAY-12 16:07:00 to 22-MAY-12 16:17:00 (CST-6)
Location: AMBROSE
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

This tornado touched down in the open country of Divide County, along the international border. There were no reports of damage associated with this tornado.

Tornado in MOUNTRAIL, NORTH DAKOTA
From 22-MAY-12 17:21:00 to 22-MAY-12 17:23:00 (CST-6)
Location: BLAISDELL
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Professional storm chasers reported this brief tornado. There were no reports of damage so the tornado is rated EF0.

Hail in BOTTINEAU, NORTH DAKOTA
From 22-MAY-12 18:50:00 to 22-MAY-12 18:55:00 (CST-6)
Location: LANSFORD
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Hail in BOTTINEAU, NORTH DAKOTA
From 22-MAY-12 18:50:00 to 22-MAY-12 18:55:00 (CST-6)
Location: LANSFORD
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Hail in MCINTOSH, NORTH DAKOTA
From 22-MAY-12 19:00:00 to 22-MAY-12 19:05:00 (CST-6)
Location: WISHEK
Magnitude: 1.75 
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Law Enforcement

The hail resulted in damage to vehicles.

Hail in MCINTOSH, NORTH DAKOTA
From 22-MAY-12 19:13:00 to 22-MAY-12 19:19:00 (CST-6)
Location: WISHEK
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in BOTTINEAU, NORTH DAKOTA
From 22-MAY-12 19:21:00 to 22-MAY-12 19:25:00 (CST-6)
Location: MAXBASS
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in MCINTOSH, NORTH DAKOTA
From 22-MAY-12 19:20:00 to 22-MAY-12 19:27:00 (CST-6)
Location: WISHEK
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in STUTSMAN, NORTH DAKOTA
From 22-MAY-12 20:00:00 to 22-MAY-12 20:05:00 (CST-6)
Location: SYDNEY
Magnitude: 1.00 
Property damage: 4.00K
Crop damage: 0.00K
Reported by: Trained Spotter

The hail damaged a car.

Hail in STUTSMAN, NORTH DAKOTA
From 22-MAY-12 20:07:00 to 22-MAY-12 20:11:00 (CST-6)
Location: (JMS)JAMESTOWN MUNI
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in LA MOURE, NORTH DAKOTA
From 22-MAY-12 20:16:00 to 22-MAY-12 20:19:00 (CST-6)
Location: JUD
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement