There has frequently been a "theme" of water, Some of the OBL images, AQ Navy talk, weapons coming through shipping containers, etc. Remember about 2 years ago the ME guy they caught on a large boat in a shipping container? Had the container outfitted almost like a small apartment for the trip, even had his laptop. (At least that's how I remember the story - I could be wrong.)
In other words, IMO, watch the ports and port cities.
I'm going to pretend that they're already here. I think it's time to focus on potential targets.