Frederick signs warn of Hurricane Irene

FREDERICK, Md. (AP) - The city of Frederick is posting warning signs in preparation for Hurricane Irene.

The city said Wednesday it has posted the yellow warning signs along streets in 11 known high-water areas.

The U.S. National Hurricane Center in Miami has upgraded the storm to a Category 3 hurricane.

Irene is expected to make landfall in North Carolina sometime over the weekend.

Federal officials say Irene could cause flooding and power outages along the East Coast as far north as Maine.