A strong cold front moved through the Great Lakes region during the evening of April 20th. Very warm and humid air pushed into the region ahead of this front. This triggered widespread thunderstorms during the afternoon, some of which produced severe wind gusts and large hail. A much stronger line of thunderstorms then passed through the region during the early evening hours. This line of thunderstorms accompanied the passage of the cold front. The strongest of these storms occurred south and east of an Owosso to Bad Axe line, many of which were accompanied by severe wind gusts.  An estimated 10,000 homes and businesses reportedly lost power during the storms. Thunderstorm winds were also responsible for blowing down a 200-foot electricity tower in Ontario, Canada, just across the St Clair River from Marysville. The tower fell onto the river. This led to a major backup of ships on the St Clair River waterways.

Thunderstorm Wind in WAYNE, MICHIGAN
From 20-APR-03 16:43:00 to 20-APR-03 16:43:00 (EST)
Location: DETROIT
Magnitude: 50 EG
Reported by: UTILITY COMPANY

Detroit Edison reported numerous tree branches blown down onto wires on the Detroit/Redford border.

Hail in SANILAC, MICHIGAN
From 20-APR-03 15:25:00 to 20-APR-03 15:25:00 (EST)
Location: LEXINGTON
Magnitude: 0.75 
Reported by: LAW ENFORCEMENT

Thunderstorm Wind in LIVINGSTON, MICHIGAN
From 20-APR-03 15:50:00 to 20-APR-03 15:50:00 (EST)
Location: PINCKNEY
Magnitude: 50 EG
Reported by: LAW ENFORCEMENT

Law enforcement reported several trees blown down in thunderstorm winds.

Thunderstorm Wind in MACOMB, MICHIGAN
From 20-APR-03 17:11:00 to 20-APR-03 17:11:00 (EST)
Location: ARMADA
Magnitude: 50 EG
Reported by: TRAINED SPOTTER

A spotter reported that thunderstorm winds blew down numerous large tree limbs.

Thunderstorm Wind in WASHTENAW, MICHIGAN
From 20-APR-03 16:00:00 to 20-APR-03 16:00:00 (EST)
Location: SALINE
Magnitude: 58 MG
Reported by: TRAINED SPOTTER

A trained weather spotter reported a 67 MPH thunderstorm wind gust.

Lightning in LIVINGSTON, MICHIGAN
From 20-APR-03 16:07:00 to 20-APR-03 16:07:00 (EST)
Location: BRIGHTON
Property damage: 50K
Reported by: NEWSPAPER

Lightning struck an electrical pole at the rear of a house and set a portion of the garage on fire.

Thunderstorm Wind in LIVINGSTON, MICHIGAN
From 20-APR-03 16:10:00 to 20-APR-03 16:10:00 (EST)
Location: BRIGHTON
Magnitude: 65 EG
Property damage: 25K
Reported by: NEWSPAPER

The newspaper reported that thunderstorm winds blew a mobile home off of its foundation.

Thunderstorm Wind in LIVINGSTON, MICHIGAN
From 20-APR-03 15:45:00 to 20-APR-03 15:45:00 (EST)
Location: PINCKNEY
Magnitude: 50 EG
Reported by: TRAINED SPOTTER

Trained weather spotters reported that thunderstorm winds blew several trees down.

Thunderstorm Wind in LAPEER, MICHIGAN
From 20-APR-03 17:15:00 to 20-APR-03 17:15:00 (EST)
Location: HADLEY
Magnitude: 50 EG
Property damage: 1K
Reported by: LAW ENFORCEMENT

Lapeer County Central Dispatch reported numerous trees and power lines blown down in thunderstorm winds.

Thunderstorm Wind in SANILAC, MICHIGAN
From 20-APR-03 17:38:00 to 20-APR-03 17:38:00 (EST)
Location: SNOVER
Magnitude: 55 EG
Property damage: 1K
Reported by: LAW ENFORCEMENT

It was reported that thunderstorm winds blew down a large tree. The tree fell onto a propane tank.

Thunderstorm Wind in MACOMB, MICHIGAN
From 20-APR-03 17:10:00 to 20-APR-03 17:10:00 (EST)
Location: UTICA
Magnitude: 50 MG
Reported by: TRAINED SPOTTER

A 59 MPH thunderstorm wind gust was measured by a storm spotter.

Thunderstorm Wind in OAKLAND, MICHIGAN
From 20-APR-03 16:23:00 to 20-APR-03 16:23:00 (EST)
Location: HIGHLAND
Magnitude: 51 EG
Reported by: TRAINED SPOTTER

A trained weather spotter reported several trees blown down in thunderstorm winds.

Thunderstorm Wind in WAYNE, MICHIGAN
From 20-APR-03 16:15:00 to 20-APR-03 16:15:00 (EST)
Location: SUMPTER
Magnitude: 51 EG
Reported by: TRAINED SPOTTER

A trained spotter estimated a thunderstorm wind gust of 60 MPH.

Thunderstorm Wind in OAKLAND, MICHIGAN
From 20-APR-03 16:20:00 to 20-APR-03 16:20:00 (EST)
Location: MILFORD
Magnitude: 51 EG
Reported by: TRAINED SPOTTER

A trained spotter estimated thunderstorm wind gusts at 60 MPH.

Thunderstorm Wind in OAKLAND, MICHIGAN
From 20-APR-03 16:25:00 to 20-APR-03 16:25:00 (EST)
Location: WHITE LAKE
Magnitude: 50 MG
Reported by: NWS EMPLOYEE(OFF DUTY)

A 58 MPH thunderstorm wind gust was measured at the National Weather Service Office

Thunderstorm Wind in WASHTENAW, MICHIGAN
From 20-APR-03 14:05:00 to 20-APR-03 14:05:00 (EST)
Location: YPSILANTI
Magnitude: 60 EG
Reported by: TRAINED SPOTTER

Spotters reported 9 to 12 inch diameter tree limbs blown down in thunderstorm winds.

Hail in MACOMB, MICHIGAN
From 20-APR-03 14:40:00 to 20-APR-03 14:40:00 (EST)
Location: UTICA
Magnitude: 0.75 
Reported by: TRAINED SPOTTER

Thunderstorm Wind in WASHTENAW, MICHIGAN
From 20-APR-03 16:15:00 to 20-APR-03 16:15:00 (EST)
Location: YPSILANTI
Magnitude: 50 EG
Reported by: TRAINED SPOTTER

Trained spotters reported several 9 inch diameter tree limbs blown down in thunderstorm winds.

Hail in OAKLAND, MICHIGAN
From 20-APR-03 14:23:00 to 20-APR-03 14:23:00 (EST)
Location: FARMINGTON
Magnitude: 0.75 
Reported by: TRAINED SPOTTER

Hail in OAKLAND, MICHIGAN
From 20-APR-03 14:30:00 to 20-APR-03 14:30:00 (EST)
Location: SOUTHFIELD
Magnitude: 0.88 
Reported by: TRAINED SPOTTER

Thunderstorm Wind in MACOMB, MICHIGAN
From 20-APR-03 14:52:00 to 20-APR-03 14:52:00 (EST)
Location: ARMADA
Magnitude: 50 EG
Reported by: TRAINED SPOTTER

Spotters reported 6 inch diameter tree limbs blown down in thunderstorm winds.

Thunderstorm Wind in WASHTENAW, MICHIGAN
From 20-APR-03 16:00:00 to 20-APR-03 16:00:00 (EST)
Location: CHELSEA
Magnitude: 52 EG
Reported by: TRAINED SPOTTER

Spotters reported that 8 to 10 inch diameter tree limbs were blown down in thunderstorm winds.

Hail in OAKLAND, MICHIGAN
From 20-APR-03 16:23:00 to 20-APR-03 16:23:00 (EST)
Location: HIGHLAND
Magnitude: 1.00 
Reported by: TRAINED SPOTTER

Thunderstorm Wind in ST. CLAIR, MICHIGAN
From 20-APR-03 15:30:00 to 20-APR-03 15:30:00 (EST)
Location: PORT HURON
Magnitude: 51 EG
Reported by: COASTAL OBSERVING STATION

A 60 MPH wind gust was measured by the Coast Guard.

Hail in WAYNE, MICHIGAN
From 20-APR-03 14:15:00 to 20-APR-03 14:15:00 (EST)
Location: REDFORD
Magnitude: 0.75 
Reported by: TRAINED SPOTTER

Hail in OAKLAND, MICHIGAN
From 20-APR-03 13:45:00 to 20-APR-03 13:45:00 (EST)
Location: WHITE LAKE
Magnitude: 0.75 
Reported by: NWS EMPLOYEE(OFF DUTY)