Ivan should move that ridge a bit to the east as it moves up the eastern seaboard -- it's motoring right now, so to speak, and I'm not so sure it's going to stall out over the mountains (thank goodness!) -- but do note that the graphic in the link you sent is best for tropical cyclones with a pressure < 940mb.

For storms more of Jeanne's ilk, try this one: http://cimss.ssec.wisc.edu/tropic/real-time/atlantic/winds/wg8dlm3.html (or just click on the 400-850hPa link on the other page). The one you linked to is for deeper storms steered moreso by the mid and upper level flow, while this one is for weaker storms steered moreso by lower- and mid-level flow.

As Ivan moves east, the ridge should move back a little to the east as well -- though perhaps become amplified due to the outflow from the storms as well as an approaching trough from the west (which I believe is stronger than the models accounted for, as it essentially eroded the ridge that yesterday was oriented along the west side of Ivan near Texas & Oklahoma). That provides the conduit for the steering path the NHC is seeing -- but it remains to be seen how exactly this plays out and whether or not the ridge builds back to the west with time to turn the system once again.