Around 3 pm CST, a fairly strong cold front was located along a line from Devils Lake, ND, to Hallock, MN. Throughout the evening, this cold front slowly sagged southward. By 6 pm CST, the front had reached a line from New Rockford, ND, to Roseau, MN. At this time, Jamestown, ND, reported a temperature of 86 degrees, while Devils Lake had dropped to 66 degrees. By midnight, the front was located along a line from Bemidji (MN) to Fargo (ND) to 20 miles south of Jamestown (ND). Behind the front, the temperature dropped to 39 degrees in Devils Lake a couple hours after midnight. Large hail, tornadoes, and flash flooding occurred during this event.

Hail in BARNES, NORTH DAKOTA
From 18-MAY-07 18:00:00 to 18-MAY-07 18:00:00 (CST-6)
Location: SIBLEY
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in STEELE, NORTH DAKOTA
From 18-MAY-07 18:00:00 to 18-MAY-07 18:00:00 (CST-6)
Location: LUVERNE
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in BENSON, NORTH DAKOTA
From 18-MAY-07 19:13:00 to 18-MAY-07 19:13:00 (CST-6)
Location: MINNEWAUKAN
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in BARNES, NORTH DAKOTA
From 18-MAY-07 19:20:00 to 18-MAY-07 19:20:00 (CST-6)
Location: SIBLEY
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in STEELE, NORTH DAKOTA
From 18-MAY-07 17:00:00 to 18-MAY-07 17:00:00 (CST-6)
Location: SHARON
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in GRIGGS, NORTH DAKOTA
From 18-MAY-07 17:30:00 to 18-MAY-07 17:30:00 (CST-6)
Location: KARNAK
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in GRIGGS, NORTH DAKOTA
From 18-MAY-07 17:25:00 to 18-MAY-07 17:25:00 (CST-6)
Location: COOPERSTOWN ARPT
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in STEELE, NORTH DAKOTA
From 18-MAY-07 17:30:00 to 18-MAY-07 17:30:00 (CST-6)
Location: LUVERNE
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Tornado in BARNES, NORTH DAKOTA
From 18-MAY-07 18:00:00 to 18-MAY-07 18:01:00 (CST-6)
Location: SIBLEY
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Three brief dust swirls were seen.

Flash Flood in CASS, NORTH DAKOTA
From 18-MAY-07 20:30:00 to 19-MAY-07 02:30:00 (CST-6)
Location: FARGO
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Street flooding was reported.

Hail in GRIGGS, NORTH DAKOTA
From 18-MAY-07 16:19:00 to 18-MAY-07 16:19:00 (CST-6)
Location: JESSIE
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in RAMSEY, NORTH DAKOTA
From 18-MAY-07 19:50:00 to 18-MAY-07 19:56:00 (CST-6)
Location: DEVILS LAKE
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in BARNES, NORTH DAKOTA
From 18-MAY-07 20:14:00 to 18-MAY-07 20:20:00 (CST-6)
Location: KOLDOK
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Tornado in BARNES, NORTH DAKOTA
From 18-MAY-07 19:50:00 to 18-MAY-07 19:51:00 (CST-6)
Location: NORTH VLY CITY
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A brief touchdown was reported in a field about 3.5 miles northeast of Valley City.

Hail in CASS, NORTH DAKOTA
From 18-MAY-07 20:04:00 to 18-MAY-07 20:09:00 (CST-6)
Location: FARGO
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CASS, NORTH DAKOTA
From 18-MAY-07 20:44:00 to 18-MAY-07 20:44:00 (CST-6)
Location: BUFFALO
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CASS, NORTH DAKOTA
From 18-MAY-07 21:20:00 to 18-MAY-07 21:20:00 (CST-6)
Location: CASSELTON
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in BARNES, NORTH DAKOTA
From 18-MAY-07 23:30:00 to 18-MAY-07 23:30:00 (CST-6)
Location: LITCHVILLE
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in TRAILL, NORTH DAKOTA
From 18-MAY-07 22:22:00 to 18-MAY-07 22:22:00 (CST-6)
Location: KELSO
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Tornado in GRIGGS, NORTH DAKOTA
From 18-MAY-07 17:52:00 to 18-MAY-07 17:53:00 (CST-6)
Location: KARNAK
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

The tornado was reported 8 miles north of Luverne on the Griggs side of the county line by a trained spotter.