One of the reasons we have been so concerned about Hurricane Irma is the very large size of the storm. One clue about this is the storm surge which is expected on the Georgia coast, far from the center of circulation.  The projected high water amount from Irma later this week is expected to be more than a foot higher than the previous record set during Hurricane Matthew last year even though Matthew went just east of Savannah.  You can see the projected water level on this graph below.