A series of electrical storms -- with vivid displays of lightning, booming thunder and heavy rain -- rumbled over parts of southern Illinois and Southeast Missouri early Tuesday.

The wind gusts of up to 40 mph disrupted electrical service to about 500 Union Electric Company customers in the Cape Girardeau area.

The series of storms began shortly after 2 a.m. and thundered until about 4.

A downed power line in the first block of Main Street tripped protective relays at the Elm Street substation, which knocked out power to parts of south Cape Girardeau. The substation wasn't put back on line until the downed electrical line was repaired.

Lightning also struck several UE pole transformers, forcing repair crews to replace the damaged transformers. The lightning blew fuses in other pole transformers that had to be replaced before service could be restored. Most of the affected UE customers had their power restored by 8 a.m.

Kevin McMeel, Cape Girardeau's assistant public works director, said a city crew was called out at 2:30 a.m. to remove several large tree limbs partially blocking city streets.

The airport weather station measured a peak wind gust of about 40 mph at 2:29 a.m. Heaviest rain at the airport occurred between 2:12 and 2:36 a.m.

Illinois State Police said the storms blew down tree limbs in parts of Union and Alexander counties, but apparently caused no serious damage or problems.

Rainfall amounts included 1.32 inches at the Jackson Fire Station, 1.1 inches at the Cape Girardeau Municipal Airport, and .60 of an inch at Marble Hill.

Forecasters at the National Weather Service at St. Charles said the storms were caused by a stream of low pressure that moved through the area overnight.

The weather service said the thunderstorms moved in an unusual direction -- west-southwestward, from southern Illinois into Southeast Missouri, -- because the upper air wind steering current is blowing southwestward across Missouri from the Great Lakes.