Based on past hurricanes and how they interact with coastal topography, 38 ft sounds to me a lot more reasonable than 50 ft for the maximum potential surge in Galveston Bay. Of course, I'm just an amateur. If TWC said 50 ft with authority, then I'd go forward with that assumption.
PS. And 38 ft is rather dreadful enough.....
You're right of course. Yesterday, we were two hours ahead in the knowledge of Rita going to 5; Everyone had to wait until it was official.