Don't take your eyes off of 90L until it is well dead. I am having nightmarish memories of TS Allison (June 2001). I was on an airplane that tried twice to land at IAH just as Allison was hitting Houston. It was an interesting night (and next day too).

While not commonplace, tropical cyclones can form amazingly fast in the northern GoM. Quoting from the NHC's Report on Allison, " No meaningful track and wind forecast statistics are available due to the limited period for which the National Hurricane Center (NHC) issued forecasts. Since the system reached storm strength quickly, there was little warning lead time. A tropical storm warning was issued at 1900 UTC 05 June from Sargent, Texas eastward along the Gulf of Mexico coast to Morgan City, Louisiana. This was less than 3 hours before tropical storm force winds were reported along the upper Texas coast. "

FWIW - Allison left 41 dead in her wake (23 in TX), and a damage estimate of $4.8 billion for Houston alone.

(While this is good info, it would be better suited to the Hurricane History Forum.)