I've just gone browsing the Satellite IR images again...

http://www.ssd.noaa.gov/PS/TROP/DATA/RT/gmex-ir4-loop.html

That trough to the north sure looks like it has become a feeder band. The eye is clearly visible. And the track is still west southwest.

If I were to guess I'd say with that trough being absorbed as a feeder band will make the system more symetric, and thus more powerful. You can already see the banding on the northside stretching out to the trough and the trouch arcing south into the hurricane. A symetric system has a better chance at strengthening.