More intense hurricanes have deeper vertical circulations, meaning that they extend to higher altitudes. At higher altitudes, the mid-latitude steering patterns are often a bit better defined than they are at lower altitudes. This manifests itself in the preferred steering layers for tropical cyclones of various intensities (see http://cimss.ssec.wisc.edu/tropic/real-time/atlantic/winds/winds-dlm.html for more). Thus, for deeper storms, there is an increased likelihood of a more northerly track.

Larger, more intense storms also often have an increased magnitude to the Beta drift, a northwestward steering flow component (just a few mph in magnitude at its peak, but still significant) that can lead to an increased poleward motion of these storms. The dynamics of the beta drift and how it comes about are beyond the scope of this discussion, but basically there are gyres within each hurricane that impart a background flow toward the NW across the center of the storm's circulation.