An upper low moving over a warm front that stretched across northern Lower Michigan set the stage for heavy rainfall on May 3rd. Training thunderstorms (storms that move over the same location) produced 5 to 7 inches of rainfall across portions of Mason and Lake counties. The heavy rainfall resulted in roads that were either flooded or washed out.  As the day progressed, strong to severe storms developed in the warm humid airmass. Golf ball size hail was reported in Mason and a 10 x 20 foot section of roof was blown off of a commercial building a few miles south of Lansing.

Thunderstorm Wind in CLINTON, MICHIGAN
From 03-MAY-12 16:45:00 to 03-MAY-12 16:45:00 (EST-5)
Location: ST JOHNS
Magnitude: 65.00 EG
Property damage: 100.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Clinton county law enforcement reported severe damage to four barns in the vicinity of DeWitt road and M-21 as well as numerous trees down in St. John's.

Strong Wind in KENT, MICHIGAN
From 03-MAY-12 17:46:00 to 03-MAY-12 17:46:00 (EST-5)
Magnitude: 45.00 EG
Property damage: 500.00K
Crop damage: 0.00K
Reported by: Amateur Radio

An amateur radio operator reported that power lines were downed two miles north northwest of Grand Rapids.

Strong Wind in LAKE, MICHIGAN
From 03-MAY-12 04:35:00 to 03-MAY-12 04:35:00 (EST-5)
Magnitude: 45.00 EG
Property damage: 500.00K
Crop damage: 0.00K
Reported by: County Official

Three trees were blown down between Irons and Baldwin.

Thunderstorm Wind in MECOSTA, MICHIGAN
From 03-MAY-12 15:00:00 to 03-MAY-12 15:00:00 (EST-5)
Location: BIG RAPIDS
Magnitude: 55.00 EG
Property damage: 0.01K
Crop damage: 0.00K
Reported by: Law Enforcement

Large Healthy Trees Down Blocking Roads in at least two different locations.

Flash Flood in MASON, MICHIGAN
From 03-MAY-12 08:20:00 to 03-MAY-12 20:00:00 (EST-5)
Location: FREESOIL
Flood cause: Heavy Rain
Property damage: 75.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Several roads were either flooded or washed out across portions of Mason county.  Radar estimated that up to 5 to 7 inches of heavy rain fell across portions of east central Mason county.  A trained spotter reported that Barnett Boulevard was washed out in South Branch.

Flash Flood in OSCEOLA, MICHIGAN
From 03-MAY-12 09:30:00 to 03-MAY-12 20:00:00 (EST-5)
Location: ORONO
Flood cause: Heavy Rain
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Radar estimated that up to 5 to 7 inches of heavy rain fell across northwest Osceola county, resulting in a few roads that were either flooded or washed out.

Hail in MASON, MICHIGAN
From 03-MAY-12 10:44:00 to 03-MAY-12 10:44:00 (EST-5)
Location: LUDINGTON
Magnitude: 0.75 
Reported by: Public

The public estimated three quarters inch hail in Ludington.

Hail in MASON, MICHIGAN
From 03-MAY-12 12:30:00 to 03-MAY-12 12:30:00 (EST-5)
Location: LUDINGTON
Magnitude: 1.75 
Property damage: 25.00K
Crop damage: 0.00K
Reported by: County Official

A county official reported hail up to one and three quarters inch in diameter in Scottville.

Hail in MASON, MICHIGAN
From 03-MAY-12 12:22:00 to 03-MAY-12 12:30:00 (EST-5)
Location: CUSTER
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reported up to one inch diameter hail in South Branch.

Hail in OCEANA, MICHIGAN
From 03-MAY-12 13:49:00 to 03-MAY-12 13:57:00 (EST-5)
Location: SHELBY
Magnitude: 1.00 
Reported by: Trained Spotter

One inch diameter hail was reported by trained spotters in Hart and near Shelby.

Hail in ALLEGAN, MICHIGAN
From 03-MAY-12 15:50:00 to 03-MAY-12 15:50:00 (EST-5)
Location: WAYLAND
Magnitude: 1.00 
Reported by: Public

The public reported one inch hail five miles south of Wayland.

Hail in MUSKEGON, MICHIGAN
From 03-MAY-12 16:20:00 to 03-MAY-12 16:20:00 (EST-5)
Location: TWIN LAKE
Magnitude: 0.75 
Reported by: Trained Spotter

A trained spotter reported three quarters inch hail and some branches down in Twin Lake.

Hail in ALLEGAN, MICHIGAN
From 03-MAY-12 16:24:00 to 03-MAY-12 16:36:00 (EST-5)
Location: WAYLAND
Magnitude: 1.00 
Reported by: Public

One inch hail was reported in Wayland.

Hail in ALLEGAN, MICHIGAN
From 03-MAY-12 15:51:00 to 03-MAY-12 15:51:00 (EST-5)
Location: BRADLEY
Magnitude: 1.25 
Reported by: Public

The public reported one and a quarter inch hail in Bradley.

Hail in CLINTON, MICHIGAN
From 03-MAY-12 17:03:00 to 03-MAY-12 17:03:00 (EST-5)
Location: MERLE BEACH
Magnitude: 0.75 
Reported by: Trained Spotter

Three quarters inch hail was reported by a trained spotter three miles south southwest of St. John's.

Hail in BARRY, MICHIGAN
From 03-MAY-12 15:51:00 to 03-MAY-12 15:51:00 (EST-5)
Location: BOWENS MILLS
Magnitude: 1.00 
Reported by: Public

One inch diameter hail was reported by the public two miles west of Bowens Mills.

Hail in KENT, MICHIGAN
From 03-MAY-12 16:20:00 to 03-MAY-12 16:20:00 (EST-5)
Location: EAST PARIS
Magnitude: 1.25 
Reported by: Trained Spotter

A trained spotter reported one and a quarter inch diameter hail near East Paris road in Kentwood.

Hail in VAN BUREN, MICHIGAN
From 03-MAY-12 17:30:00 to 03-MAY-12 17:30:00 (EST-5)
Location: GOBLES WIDNERS ARPT
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Three quarters inch hail was reported by a trained spotter near Gobles.

Hail in BARRY, MICHIGAN
From 03-MAY-12 17:57:00 to 03-MAY-12 17:57:00 (EST-5)
Location: NASHVILLE
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Three quarters inch hail was reported in Nashville.

Hail in EATON, MICHIGAN
From 03-MAY-12 18:00:00 to 03-MAY-12 18:00:00 (EST-5)
Location: SUNFIELD
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

An amateur radio operator reported three quarters inch hail in Sunfield.

Hail in KALAMAZOO, MICHIGAN
From 03-MAY-12 17:25:00 to 03-MAY-12 17:25:00 (EST-5)
Location: (AZO)KALAMAZOO ARPT
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A trained spotter reported one inch diameter hail in Kalamazoo.

Hail in INGHAM, MICHIGAN
From 03-MAY-12 18:30:00 to 03-MAY-12 18:35:00 (EST-5)
Location: MASON
Magnitude: 1.25 
Reported by: Trained Spotter

A trained spotter measured hail up to an inch and a quarter in diameter in Mason.

Thunderstorm Wind in INGHAM, MICHIGAN
From 03-MAY-12 18:35:00 to 03-MAY-12 18:35:00 (EST-5)
Location: HOLT
Magnitude: 61.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Ingham county emergency management reported that a ten by twenty foot section of a roof was ripped off a commercial building.  It was also reported that about 300 yards of power poles along Aurelius road were toppled.

Hail in JACKSON, MICHIGAN
From 03-MAY-12 21:20:00 to 03-MAY-12 21:22:00 (EST-5)
Location: WOODVILLE
Magnitude: 2.00 
Reported by: Trained Spotter

A trained spotter reported hail up to two inches in diameter two miles southeast of Jackson with one inch hail in Jackson.

Thunderstorm Wind in MONTCALM, MICHIGAN
From 03-MAY-12 17:58:00 to 03-MAY-12 17:58:00 (EST-5)
Location: AMSDEN
Magnitude: 70.00 EG
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Broadcast Media

The broadcast media reported that peak winds estimated near 80 mph caused damage to a barn and unroofed an outbuilding two miles northwest of Fenwick.  Several healthy trees were snapped or uprooted.

Flash Flood in LAKE, MICHIGAN
From 03-MAY-12 09:00:00 to 03-MAY-12 18:00:00 (EST-5)
Location: BRANCH
Flood cause: Heavy Rain
Property damage: 70.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Radar estimated that up to 5 to 7 inches of heavy rain fell across a fairly large part of Lake county resulting in several roads that were either flooded or washed out.