Erin isn't as intense as it once was. But its large size is what matters most. While it won't landfall, it will bring high surf and rip currents to much of the East Coast. And it could bring damaging surge flooding for some.

North Carolina expects coastal flooding from massive waves, tropical-storm-force winds and tidal and storm surges for much of the state shoreline, especially the Outer Banks, as well as life-threatening rip currents for most of the week, Stein said, adding, "No one should be in the ocean."