A derecho track along a stalled frontal boundary which was located over northern Indiana and Ohio during the early afternoon hours of the 21st. Washtenaw County was one of the hardest hit, with 28,000 homes losing power.

Hail in WAYNE, MICHIGAN
From 21-MAY-04 13:50:00 to 21-MAY-04 13:50:00 (EST)
Location: DETROIT
Magnitude: 0.75 
Reported by: TRAINED SPOTTER

Thunderstorm Wind in MACOMB, MICHIGAN
From 21-MAY-04 14:15:00 to 21-MAY-04 14:15:00 (EST)
Location: UTICA
Magnitude: 56 EG
Reported by: TRAINED SPOTTER

A trained spotter estimated a 65 mph thunderstorm wind gust.

Hail in LENAWEE, MICHIGAN
From 21-MAY-04 13:05:00 to 21-MAY-04 13:05:00 (EST)
Location: ADRIAN
Magnitude: 1.00 
Reported by: TRAINED SPOTTER

Thunderstorm Wind in LIVINGSTON, MICHIGAN
From 21-MAY-04 13:00:00 to 21-MAY-04 13:00:00 (EST)
Location: HAMBURG
Magnitude: 52 EG
Reported by: EMERGENCY MANAGER

The emergency manager reported trees and wires down.

Thunderstorm Wind in WASHTENAW, MICHIGAN
From 21-MAY-04 13:20:00 to 21-MAY-04 13:20:00 (EST)
Location: SALINE
Magnitude: 56 MG
Reported by: TRAINED SPOTTER

Hail in MONROE, MICHIGAN
From 21-MAY-04 13:20:00 to 21-MAY-04 13:20:00 (EST)
Location: CARLETON
Magnitude: 0.75 
Reported by: TRAINED SPOTTER

Hail in WAYNE, MICHIGAN
From 21-MAY-04 13:25:00 to 21-MAY-04 13:25:00 (EST)
Location: DEARBORN
Magnitude: 0.88 
Reported by: TRAINED SPOTTER

Thunderstorm Wind in WAYNE, MICHIGAN
From 21-MAY-04 13:25:00 to 21-MAY-04 13:25:00 (EST)
Location: DEARBORN
Magnitude: 56 EG
Reported by: TRAINED SPOTTER

A trained spotter estimated a 65 mph thunderstorm wind gust.

Hail in WAYNE, MICHIGAN
From 21-MAY-04 13:28:00 to 21-MAY-04 13:28:00 (EST)
Location: SHELDON
Magnitude: 1.00 
Reported by: TRAINED SPOTTER

Hail in WAYNE, MICHIGAN
From 21-MAY-04 13:35:00 to 21-MAY-04 13:35:00 (EST)
Location: REDFORD
Magnitude: 0.75 
Reported by: TRAINED SPOTTER

Thunderstorm Wind in WAYNE, MICHIGAN
From 21-MAY-04 13:35:00 to 21-MAY-04 13:35:00 (EST)
Location: TAYLOR
Magnitude: 56 EG
Reported by: TRAINED SPOTTER

A trained spotter estimated a 65 mph thunderstorm wind gust.

Thunderstorm Wind in OAKLAND, MICHIGAN
From 21-MAY-04 13:50:00 to 21-MAY-04 13:50:00 (EST)
Location: TROY
Magnitude: 56 MG
Reported by: TRAINED SPOTTER

A trained spotter measure a 65 mph thunderstorm wind gust. Trees were also reported blown down.

Thunderstorm Wind in WAYNE, MICHIGAN
From 21-MAY-04 13:28:00 to 21-MAY-04 13:28:00 (EST)
Location: SHELDON
Magnitude: 52 EG
Reported by: TRAINED SPOTTER

A trained spotter estimated a 60 mph thunderstorm wind gust.

Thunderstorm Wind in WAYNE, MICHIGAN
From 21-MAY-04 13:28:00 to 21-MAY-04 13:28:00 (EST)
Location: ROMULUS
Magnitude: 61 EG
Reported by: TRAINED SPOTTER

A trained spotter estimated a 70 mph thunderstorm wind gust.

Hail in WAYNE, MICHIGAN
From 21-MAY-04 13:30:00 to 21-MAY-04 13:30:00 (EST)
Location: WESTLAND
Magnitude: 0.75 
Reported by: TRAINED SPOTTER

Thunderstorm Wind in WASHTENAW, MICHIGAN
From 21-MAY-04 13:01:00 to 21-MAY-04 13:01:00 (EST)
Location: SALINE
Magnitude: 52 EG
Reported by: EMERGENCY MANAGER

The emergency manager reported 8 inch tree limbs down.

Hail in WASHTENAW, MICHIGAN
From 21-MAY-04 13:01:00 to 21-MAY-04 13:01:00 (EST)
Location: SALINE
Magnitude: 1.00 
Reported by: EMERGENCY MANAGER

Thunderstorm Wind in WASHTENAW, MICHIGAN
From 21-MAY-04 13:05:00 to 21-MAY-04 13:05:00 (EST)
Location: (ARB)ANN ARBOR MUNI
Magnitude: 53 MG
Reported by: AWOS,ASOS,MESONET,ETC

Hail in WASHTENAW, MICHIGAN
From 21-MAY-04 13:05:00 to 21-MAY-04 13:05:00 (EST)
Location: YPSILANTI
Magnitude: 0.75 
Reported by: TRAINED SPOTTER

Thunderstorm Wind in WASHTENAW, MICHIGAN
From 21-MAY-04 13:00:00 to 21-MAY-04 13:00:00 (EST)
Location: ANN ARBOR
Magnitude: 65 EG
Reported by: EMERGENCY MANAGER

Ten utility poles were toppled along Wagner Road between Scio Church and Ellsworth Roads in Lodi Township.

Thunderstorm Wind in OAKLAND, MICHIGAN
From 21-MAY-04 13:30:00 to 21-MAY-04 13:30:00 (EST)
Location: BLOOMFIELD HILLS
Magnitude: 52 EG
Reported by: TRAINED SPOTTER

A trained spotter estimated a 60 mph thunderstorm wind gust.

Hail in WAYNE, MICHIGAN
From 21-MAY-04 13:38:00 to 21-MAY-04 13:38:00 (EST)
Location: DEARBORN HGTS
Magnitude: 0.75 
Reported by: TRAINED SPOTTER

Thunderstorm Wind in OAKLAND, MICHIGAN
From 21-MAY-04 13:40:00 to 21-MAY-04 13:40:00 (EST)
Location: ROCHESTER HILLS
Magnitude: 55 MG
Reported by: TRAINED SPOTTER

Flash Flood in OAKLAND, MICHIGAN
From 21-MAY-04 13:55:00 to 21-MAY-04 14:25:00 (EST)
Location: WATERFORD
Reported by: LAW ENFORCEMENT

Dixie Highway in Waterford was flooded with a foot of water.

Thunderstorm Wind in WASHTENAW, MICHIGAN
From 21-MAY-04 13:20:00 to 21-MAY-04 13:20:00 (EST)
Location: YPSILANTI
Magnitude: 60 MG
Reported by: AWOS,ASOS,MESONET,ETC

Flash Flood in WAYNE, MICHIGAN
From 21-MAY-04 13:36:00 to 21-MAY-04 14:45:00 (EST)
Location: CENTRAL PORTION
Reported by: LAW ENFORCEMENT

Flooding was reported along I-94 and Telegraph.

Thunderstorm Wind in MACOMB, MICHIGAN
From 21-MAY-04 13:56:00 to 21-MAY-04 13:56:00 (EST)
Location: ROSEVILLE
Magnitude: 65 EG
Reported by: TRAINED SPOTTER

A trained spotter estimated a 75 mph thunderstorm wind gust. Numerous trees were also reported down.

Thunderstorm Wind in ST. CLAIR, MICHIGAN
From 21-MAY-04 14:30:00 to 21-MAY-04 14:30:00 (EST)
Location: ALGONAC
Magnitude: 52 EG
Reported by: TRAINED SPOTTER

A trained spotter reported trees blown down.

Thunderstorm Wind in OAKLAND, MICHIGAN
From 21-MAY-04 13:25:00 to 21-MAY-04 13:25:00 (EST)
Location: CLARKSTON
Magnitude: 60 EG
Reported by: TRAINED SPOTTER

A trained spotter estimated a 60 mph thunderstorm wind gust. Large tree limbs were also reported down.

Flash Flood in WASHTENAW, MICHIGAN
From 21-MAY-04 13:29:00 to 21-MAY-04 14:29:00 (EST)
Location: COUNTYWIDE
Reported by: LAW ENFORCEMENT

Several reports of flooded roads, some of which were four feet deep.

Thunderstorm Wind in LENAWEE, MICHIGAN
From 21-MAY-04 12:45:00 to 21-MAY-04 12:45:00 (EST)
Location: CAMBRIDGE JCT
Magnitude: 52 EG
Reported by: TRAINED SPOTTER

A trained spotter estimated a 60 mph thunderstorm wind gust.

Hail in LENAWEE, MICHIGAN
From 21-MAY-04 12:50:00 to 21-MAY-04 12:50:00 (EST)
Location: ADDISON
Magnitude: 1.75 
Reported by: LAW ENFORCEMENT

Thunderstorm Wind in SHIAWASSEE, MICHIGAN
From 21-MAY-04 12:35:00 to 21-MAY-04 12:35:00 (EST)
Location: VERNON
Magnitude: 56 EG
Reported by: TRAINED SPOTTER

A trained spotter estimated a 65 mph thunderstorm wind gust.

Hail in LENAWEE, MICHIGAN
From 21-MAY-04 12:45:00 to 21-MAY-04 12:45:00 (EST)
Location: CAMBRIDGE JCT
Magnitude: 1.00 
Reported by: TRAINED SPOTTER

Hail in WAYNE, MICHIGAN
From 21-MAY-04 13:30:00 to 21-MAY-04 13:30:00 (EST)
Location: ROMULUS
Magnitude: 1.75 
Reported by: TRAINED SPOTTER

Hail in WASHTENAW, MICHIGAN
From 21-MAY-04 13:30:00 to 21-MAY-04 13:30:00 (EST)
Location: MILAN
Magnitude: 0.75 
Reported by: TRAINED SPOTTER

Thunderstorm Wind in WASHTENAW, MICHIGAN
From 21-MAY-04 13:30:00 to 21-MAY-04 13:30:00 (EST)
Location: MILAN
Magnitude: 55 EG
Reported by: TRAINED SPOTTER

Numerous trees were blown down.

Hail in MONROE, MICHIGAN
From 21-MAY-04 13:33:00 to 21-MAY-04 13:33:00 (EST)
Location: SOUTH ROCKWOOD
Magnitude: 0.75 
Reported by: GENERAL PUBLIC

Thunderstorm Wind in LIVINGSTON, MICHIGAN
From 21-MAY-04 12:45:00 to 21-MAY-04 12:45:00 (EST)
Location: GREGORY
Magnitude: 52 EG
Reported by: EMERGENCY MANAGER

Numerous trees were blown down.

Thunderstorm Wind in WASHTENAW, MICHIGAN
From 21-MAY-04 12:55:00 to 21-MAY-04 12:55:00 (EST)
Location: CHELSEA
Magnitude: 56 EG
Reported by: GENERAL PUBLIC

A person from the general public estimated a 65 mph thunderstorm wind gust.

Thunderstorm Wind in MONROE, MICHIGAN
From 21-MAY-04 13:20:00 to 21-MAY-04 13:20:00 (EST)
Location: MILAN
Magnitude: 83 EG
Reported by: GENERAL PUBLIC

A person from the general public estimated a 95 mph thunderstorm wind gust.

Hail in MONROE, MICHIGAN
From 21-MAY-04 13:20:00 to 21-MAY-04 13:20:00 (EST)
Location: MILAN
Magnitude: 0.75 
Reported by: GENERAL PUBLIC

Hail in WASHTENAW, MICHIGAN
From 21-MAY-04 13:20:00 to 21-MAY-04 13:20:00 (EST)
Location: YPSILANTI
Magnitude: 2.00 
Reported by: TRAINED SPOTTER

Thunderstorm Wind in WASHTENAW, MICHIGAN
From 21-MAY-04 13:20:00 to 21-MAY-04 13:20:00 (EST)
Location: SALEM
Magnitude: 52 EG
Reported by: TRAINED SPOTTER

A trained weather spotter reported small trees blown down.

Hail in WASHTENAW, MICHIGAN
From 21-MAY-04 13:20:00 to 21-MAY-04 13:20:00 (EST)
Location: SALINE
Magnitude: 1.00 
Reported by: TRAINED SPOTTER

Thunderstorm Wind in LENAWEE, MICHIGAN
From 21-MAY-04 12:50:00 to 21-MAY-04 12:50:00 (EST)
Location: ADDISON
Magnitude: 61 EG
Reported by: LAW ENFORCEMENT

Law enforcement estimated a 70 mph thunderstorm wind gust.

Thunderstorm Wind in LENAWEE, MICHIGAN
From 21-MAY-04 12:59:00 to 21-MAY-04 12:59:00 (EST)
Location: TECUMSEH
Magnitude: 52 EG
Reported by: TRAINED SPOTTER

A trained spotter estimated a 60 mph thunderstorm wind gust.

Hail in LENAWEE, MICHIGAN
From 21-MAY-04 13:00:00 to 21-MAY-04 13:03:00 (EST)
Location: ADRIAN
Magnitude: 0.75 
Reported by: TRAINED SPOTTER

Thunderstorm Wind in WASHTENAW, MICHIGAN
From 21-MAY-04 13:10:00 to 21-MAY-04 13:10:00 (EST)
Location: ANN ARBOR
Magnitude: 52 EG
Reported by: TRAINED SPOTTER

A trained spotter estimated a 60 mph thunderstorm wind gust.

Thunderstorm Wind in WASHTENAW, MICHIGAN
From 21-MAY-04 13:15:00 to 21-MAY-04 13:15:00 (EST)
Location: ANN ARBOR
Magnitude: 70 EG
Reported by: TRAINED SPOTTER

A trained spotter estimated a 80 mph thunderstorm wind gust.

Thunderstorm Wind in LIVINGSTON, MICHIGAN
From 21-MAY-04 13:15:00 to 21-MAY-04 13:15:00 (EST)
Location: BRIGHTON
Magnitude: 54 EG
Reported by: EMERGENCY MANAGER

The emergency manager reported numerous trees and wires down.