I agree. If Isidore was to have a North Mexican or south Texas landfall - UKmet's solution I think there are 3 possibilities. 1) Continues to head W into TX/MX (least likely IMHO); 2) comes up north ahead of the next shortwave after the one you mentioned and gives Eastern TX all the rain they can handle (second least likely); 3) re-emerges out in the Gulf and heads off to the FL Panhandle at a pretty quick speed as probably a Cat-1.

Do you see any other logical possibilites in the event of a North Mex/South TX landfall?

Steve