My sister works at the Houston Space Center (yes, she is a rocket scientist), and lives on the bay in League City. If a 20' storm surge pushes into Galveston Bay, they'll have some major flooding. The Space Center sent everyone home at noon yesterday, and said to come back Monday. I think they're going down to San Antonio for a couple of days.
My daughter's family lives between Dallas and Ft. Worth. They don't expect much worse than Spring type thunderstorms, but tornadoes do pop up around the fringes of hurricanes.