Ivan is currently restructuring itself which is likely why it looks like it is wobbling west. This process should complete over the next few hours, and I would expect more of a shift after that. The current averaged motion of 300 deg. is only 15 deg. from true NW, so that is not much of a change. Here are 2 links of interest, the first has some nice graphics, the second is a water vapor sat pic which shows the strong trough digging in the central plains.