18Z Model Isaac Roundup:
GFDL: takes Isaac into south Florida. Dade or Broward County Sunday night after moving through Hispaniola, and north of Cuba. Days.Link
HWRF:Over Hispaniola and rides the north coast of Cuba, never making much further by Monday link
CMC:Over Hispaniola and stays east of Florida by Monday
GFS: takes it over the keys late Monday, over southwestern Florida and out into the Gulf near Tampa Bay Tuesday night, and landfall in the big Bend near Apalachee Bay on Wednesday night (same area where the worst flooding from Debby occurred) (18z - link)
EURO (12z): Takes it south of islands, through the Yucatan Channel into the Gulf, avoiding land the entire time. (link)

In short a lot of different possibilities at this point.