A tornado warning has been issued for parts of Virginia, including the cities of Richmond and Richmond-Somerset, and golf courses in the areas.
The National Weather Service said the strongest winds and lightning could strike on Wednesday, with some areas seeing up to three inches of rain.
It said the rain was expected to dissipate by late morning.
A tornado warning remains in effect for the cities and golf course in Richmond and the towns of Westfield and New Castle.
The weather service issued the warning for parts near the city of Westbury, including Westfield-Plymouth, and the town of New Castle, about 60 miles (100 km) north of Richmond.
The storms could be particularly hazardous for people in areas where flooding could cause significant damage.
It is possible that some roads in Westfield could be closed, according to the weather service.
It was not immediately clear how many people might be in danger, the weather agency said.
It also said it was not yet known how long it would take for the storms to move inland and potentially cause serious damage.