Generally you've made a good observation, however, note that the main ball of convection is displaced to the west of the tropical low center under the influence of strong east to east northeast winds. At 28/12Z, NHC estimated the ill-defined center location at 10.5N 36.0W but other small swirls are also evident in the visible satellite imagery. My guesstimate at 13Z would be 10.5N 37.2W with a general motion just south of due west (260 degrees). With uncertainty on the initialization point, most (if not all) of the 00Z and 06Z model runs have already been too far to the north on their 6 and/or 12 hour forecast points. This 'bouncing around' with the models will settle down as the system becomes better defined and a consistent centerpoint becomes better established. Until this happens though (and it may take a couple of days), any aggresive northward trend by the models will remain suspect and a generally westward motion is more likely. Its also worth noting that the central pressure has increased in the past 24 hours from 1009MB to 1011MB, so development of this system is likely to be slow until the convection aligns better with the center of the low.
Cheers,
ED