In the mid afternoon hours of Sunday, August 1st, Severe Thunderstorm Watch number 559 was issued for much of western and north central North Dakota. Later, during early Sunday evening, the watch was expanded to include south central North Dakota. A remnant outflow boundary across northeast Montana and northwest North Dakota was the focus for isolated supercells as they tracked east-southeast from northwest North Dakota in the afternoon, into south central North Dakota in the evening. Additional thunderstorm development took place across north central North Dakota, where mid level short wave impulses provided the necessary lift along a surface trough.
Several severe thunderstorm and tornado warnings were issued. Multiple reports of large hail, several reports of severe thunderstorm winds, and two confirmed tornadoes occurred during this episode.

Thunderstorm Wind in MCKENZIE, NORTH DAKOTA
From 01-AUG-10 15:02:00 to 01-AUG-10 15:09:00 (MST-7)
Location: WATFORD CITY
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Estimated winds of 60 mph were reported.

Funnel Cloud in MCKENZIE, NORTH DAKOTA
From 01-AUG-10 15:43:00 to 01-AUG-10 15:48:00 (MST-7)
Location: MANDAREE
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Several funnel clouds appeared underneath a rotating wall cloud. The funnel clouds did not reach the surface.

Hail in ROLETTE, NORTH DAKOTA
From 01-AUG-10 18:15:00 to 01-AUG-10 18:22:00 (CST-6)
Location: DUNSEITH
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Thunderstorm Wind in MORTON, NORTH DAKOTA
From 01-AUG-10 20:13:00 to 01-AUG-10 20:21:00 (CST-6)
Location: SWEET BRIAR
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Estimated winds of 60 mph were reported.

Hail in WILLIAMS, NORTH DAKOTA
From 01-AUG-10 15:00:00 to 01-AUG-10 15:15:00 (CST-6)
Location: TRENTON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: SHAVE Project

Hail in WILLIAMS, NORTH DAKOTA
From 01-AUG-10 15:30:00 to 01-AUG-10 15:45:00 (CST-6)
Location: WILLISTON
Magnitude: 1.50 
Property damage: 35.00K
Crop damage: 0.00K
Reported by: SHAVE Project

Hail in OLIVER, NORTH DAKOTA
From 01-AUG-10 19:28:00 to 01-AUG-10 19:38:00 (CST-6)
Location: HANNOVER
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in MCKENZIE, NORTH DAKOTA
From 01-AUG-10 15:15:00 to 01-AUG-10 15:21:00 (MST-7)
Location: KEENE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in WILLIAMS, NORTH DAKOTA
From 01-AUG-10 15:20:00 to 01-AUG-10 15:28:00 (CST-6)
Location: WILLISTON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in MORTON, NORTH DAKOTA
From 01-AUG-10 19:48:00 to 01-AUG-10 19:57:00 (CST-6)
Location: NEW SALEM
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Estimated winds of 60 mph were reported.

Hail in MORTON, NORTH DAKOTA
From 01-AUG-10 20:00:00 to 01-AUG-10 20:10:00 (CST-6)
Location: NEW SALEM
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Funnel Cloud in MORTON, NORTH DAKOTA
From 01-AUG-10 20:10:00 to 01-AUG-10 20:14:00 (CST-6)
Location: JUDSON
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A brief funnel cloud was reported from a trained spotter traveling on Interstate 94 west of Mandan.

Hail in WILLIAMS, NORTH DAKOTA
From 01-AUG-10 15:30:00 to 01-AUG-10 15:40:00 (CST-6)
Location: WILLISTON
Magnitude: 1.75 
Property damage: 40.00K
Crop damage: 0.00K
Reported by: SHAVE Project

Windows were broken on the north side of a home, and car windshields were broken out.

Hail in WILLIAMS, NORTH DAKOTA
From 01-AUG-10 15:30:00 to 01-AUG-10 15:40:00 (CST-6)
Location: WILLISTON
Magnitude: 1.75 
Property damage: 12.00K
Crop damage: 0.00K
Reported by: SHAVE Project

A camper and truck were dented.

Thunderstorm Wind in MORTON, NORTH DAKOTA
From 01-AUG-10 19:46:00 to 01-AUG-10 19:53:00 (CST-6)
Location: NEW SALEM
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Estimated winds of 60 mph were reported.

Hail in MORTON, NORTH DAKOTA
From 01-AUG-10 19:45:00 to 01-AUG-10 19:53:00 (CST-6)
Location: NEW SALEM
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in WILLIAMS, NORTH DAKOTA
From 01-AUG-10 15:30:00 to 01-AUG-10 15:32:00 (CST-6)
Location: WILLISTON
Magnitude: 1.75 
Property damage: 35.00K
Crop damage: 0.00K
Reported by: SHAVE Project

Damage was sustained to vehicles and siding on a home.

Tornado in MERCER, NORTH DAKOTA
From 01-AUG-10 20:16:00 to 01-AUG-10 20:21:00 (CST-6)
Location: BEULAH
Tornado F-scale: EF0
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Newspaper

A tornado touched down in Mercer County and impacted a farmstead. A large cottonwood tree was uprooted and two grain bins were destroyed. The damage corresponded to a middle EF0 on the Enhanced Fujita Tornado Scale. From that it was determined that wind speeds were around 75 mph.

Tornado in ROLETTE, NORTH DAKOTA
From 01-AUG-10 20:45:00 to 01-AUG-10 21:01:00 (CST-6)
Location: ROLETTE
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

This tornado occurred in the open country. No structures were impacted, so no damage was done. The Rolla Fire Department was also reporting this tornado to the National Weather Service in real time.

Thunderstorm Wind in MORTON, NORTH DAKOTA
From 01-AUG-10 20:00:00 to 01-AUG-10 20:10:00 (CST-6)
Location: NEW SALEM
Magnitude: 70.00 EG
Property damage: 150.00K
Crop damage: 250.00K
Reported by: Law Enforcement

Large hail accompanied the strong thunderstorm winds. The wind driven hail and strong winds resulted in widespread damage in the town of New Salem. Several trees were uprooted, and hail damage was sustained to homes and vehicles.

Hail in WILLIAMS, NORTH DAKOTA
From 01-AUG-10 15:02:00 to 01-AUG-10 15:13:00 (CST-6)
Location: TRENTON
Magnitude: 1.00 
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Trained Spotter

The large hail resulted in broken windows on a home.