I would doubt that it is pushing a Katrina-type surge anyway. Large eyewalls and large geographic storms tend to push more water than their windspeeds and pressure would indicate. Charley was a small (almost midget) hurricane. Storm surge was not as bad with Charley as it would have been had it been a typical Cat 4 in structure.
Of course, Charley did not have surge momentum either due to its rapid intensification prior to hitting land.
Coveresly, Ivan landed as a Cat 3 but pushed a borderline Cat 4/5 surge onto Perdido Key straddling the Alabama/Florida line. In addition, Ivan did have the surge momentum of its prior long-lived Category 5 status.

Camille was a strong, small hurricane that did have surge momentum. In addition, it actually hit as a 5. Its surge was in the 20-25 feet range. Contrast that with Katrina, which also had surge momentum, but was geographically very large producing a larger surge than Camille. That larger surge translated into a larger surge momentum which did not , unfortunately, have enough time to dissapate prior to hitting shore. The surge on Katrina will be 30+ ft.

So, you are correct in that a sharp turn would greatly affect the surge momentum. So, the main question will be how strong will it be and how long will it be that strong after it makes the turn. Also, will an ERC cause a larger eye? These are the questions that we must ask.

I would also like to not neglect the fact that the "angle of attack" to the shoreline is very important. If I had to guess, (and this is only a guess) I would say that the surge is in the 18-20' range with this storm (which, of course, is still terrible).