From Eric Holthaus:

So, worryingly, here’s the now *likely* scenario for Hurricane #Florence:

– Rapid intensification over the next 36-48 hrs to major hurricane status
– Landfall in the Carolinas as a Category 4
– Stalling near the coast for up to an additional *six days*, flooding rain in NC + VA

The NHC explicitly mentioned the latter scenario in their latest (11pm) discussion: “One thing all models coincide at the longer range is with the collapsing of the steering currents, resulting in a significant reduction of the forward speed of the hurricane.”

From  

00z GFS literally dumps 8 FEET of rain offshore of the Carolinas as sits stationary for days. (single model run disclaimer) That said, the potential for stalling / looping is very real / physical, and these incredible rainfall amounts are more credible than you think.