Hurricane Isabel passed well to the south of Norfolk, and yet it caused extreme flooding and power outages throughout this region. Why?

If the low pressure is south of you and you are on the east coast, the counterclockwise rotation of air around the core of the storm is a breeze from the east where you are. That East wind brings waves, rise in sea level (called "storm surge" lately), and very wet air in from the Atlantic Ocean east of you. That all roars into the Chesapeake Bay and piles against Norfolk.