A warm front moved north across lower Michigan on the 12th, ushering in another warm, muggy, unstable air mass.  Thunderstorms developed northeast of Grand Rapids in the afternoon, then moved east toward the Saginaw Valley and Thumb areas.  One storm evolved into a classic supercell, producing baseball sized hail from just east of Bay City to near Sebewaing.  The supercell continued east across Huron County, and produced the first tornado of the severe weather season a few miles north of White Rock.  Many trees were downed near the Lake Huron shoreline, with some downed onto homes.  A storage shed was blown into a neighbor's yard, a swimming pool was destroyed, and several canoes were damaged.Several other storms moved across Huron County, dumping up to 5 inches of rain in some parts of the county.  Flash flooding resulted in the Pigeon/Elkton area.  A trailer park in Elkton had to be evacuated as the Pinnebog River quickly rose out of its banks.  Water rose as high as the electric meters on some of the mobile homes.  High water lingered in the county through the night, with flooding along the Willow River in Bloomfield Township (Redman Road was closed for a time), and street flooding in Harbor Beach.Additional storms developed further south in the evening, and moved east across metro Detroit.  These storms produced marginally severe hail, and sporadic wind damage in the form of downed trees and power lines.

Hail in WAYNE, MICHIGAN
From 12-MAY-00 21:31:00 to 12-MAY-00 21:31:00 (EST)
Location: WESTLAND
Magnitude: 0.75 
Reported by: TRAINED SPOTTER

Hail in WAYNE, MICHIGAN
From 12-MAY-00 21:50:00 to 12-MAY-00 21:50:00 (EST)
Location: DETROIT
Magnitude: 0.88 
Reported by: TRAINED SPOTTER

Flood in HURON, MICHIGAN
From 12-MAY-00 23:45:00 to 13-MAY-00 09:00:00 (EST)
Property damage: 20K
Reported by: NEWSPAPER

Hail in BAY, MICHIGAN
From 12-MAY-00 17:10:00 to 12-MAY-00 17:10:00 (EST)
Location: BAY CITY
Magnitude: 2.75 
Reported by: TRAINED SPOTTER

Hail in TUSCOLA, MICHIGAN
From 12-MAY-00 17:16:00 to 12-MAY-00 17:16:00 (EST)
Location: UNIONVILLE
Magnitude: 1.75 
Reported by: BROADCAST MEDIA

Flash Flood in HURON, MICHIGAN
From 12-MAY-00 21:00:00 to 12-MAY-00 23:45:00 (EST)
Location: PIGEON
Property damage: 35K
Reported by: LAW ENFORCEMENT

Hail in OAKLAND, MICHIGAN
From 12-MAY-00 21:15:00 to 12-MAY-00 21:15:00 (EST)
Location: NOVI
Magnitude: 0.75 
Reported by: LAW ENFORCEMENT

Thunderstorm Wind in MACOMB, MICHIGAN
From 12-MAY-00 21:30:00 to 12-MAY-00 21:30:00 (EST)
Location: RAY CENTER
Magnitude: 52 E
Property damage: 4K
Reported by: UNKNOWN

Thunderstorm Wind in OAKLAND, MICHIGAN
From 12-MAY-00 21:12:00 to 12-MAY-00 21:12:00 (EST)
Location: WIXOM
Magnitude: 50 E
Property damage: 2K
Reported by: LAW ENFORCEMENT

Hail in BAY, MICHIGAN
From 12-MAY-00 16:30:00 to 12-MAY-00 16:43:00 (EST)
Location: BAY CITY
Magnitude: 0.88 
Reported by: TRAINED SPOTTER

Thunderstorm Wind in OAKLAND, MICHIGAN
From 12-MAY-00 21:12:00 to 12-MAY-00 21:12:00 (EST)
Location: CLARKSTON
Magnitude: 52 E
Property damage: 6K
Reported by: LAW ENFORCEMENT

Hail in HURON, MICHIGAN
From 12-MAY-00 17:23:00 to 12-MAY-00 17:25:00 (EST)
Location: SEBEWAING
Magnitude: 2.75 
Reported by: FIRE DEPT/RESCUE SQUAD

Thunderstorm Wind in LIVINGSTON, MICHIGAN
From 12-MAY-00 20:41:00 to 12-MAY-00 20:41:00 (EST)
Location: FOWLERVILLE
Magnitude: 52 E
Property damage: 2K
Reported by: TRAINED SPOTTER

Tornado in HURON, MICHIGAN
From 12-MAY-00 18:50:00 to 12-MAY-00 18:50:00 (EST)
Location: WHITE ROCK
Tornado F-scale: F1
Property damage: 60K
Reported by: NWS STORM SURVEY

Thunderstorm Wind in LIVINGSTON, MICHIGAN
From 12-MAY-00 21:10:00 to 12-MAY-00 21:10:00 (EST)
Location: HARTLAND
Magnitude: 52 E
Property damage: 6K
Reported by: TRAINED SPOTTER