http://www.ssd.noaa.gov/goes/flt/t1/sloop-bd.html

Looking at the Dvorak loop there, the only theory I have for this "thing" on the NW side of the storm is that it's making it look a bit more like it's becoming an annular hurricane on Dvorak (newest image in the loop, 2:15 utc illustrates this well)

Observe the northern outflow, and you can clearly see that the area of the darker greys has diminished quite a bit.

So maybe this has to do with becoming annular? We'll just have to wait and see if the current "trend" continues.

Edit: forgot to add that cloud tops seem to be warming as well with each image.