Having been to that area several times, anything over 20 inches is going to be awful. Add it to a category 3 storm surge, and 100 mph winds, and there are coastal communities that will be obliterated, and may not be rebuilt.
No question the wide area amounts of 20 which seems quite likely, are going to fill rivers to record levels. That’s probably going to be the main problem. Hopefully the surge and highest winds will hit a less populated part of the coast. Remember that the incoming eyewall is only about 25-50 miles on the right side of the storm where the worst conditions are