I was tempted to title this post 'The Mess Called 91L - Either One, Take Your Pick'. Anyway, I decided to put this here so that it could survive being EDited by myself
The right/east half of 91L has a mid to high level circulation, well defined but weakening, located at 15N 52.3W at 31/18Z. This center is moving slowly west.
The right/east half of 91L has a weak LLCC located at 13.5N 52.5W at 31/18Z which is also moving west.
The left/west half of 91L has its most predominant center (there are others - which is not bad for a so-called wind surge) located at 12N 58W at 31/18Z and it is also moving west. Both halves were evident yesterday - they were just in closer proximity to one another.
The left/west half has a better environment for development while the right/east half has better overall organization. I believe that recon is heading toward this right/east half but someone else can confirm that either way. The current best candidate for eventual tropical cyclone designation is the left/west half - but it will take awhile to get there.
At 31/12Z, the GFDL was initialized at 12.9N 51.5W - which is useless if the right/east half falls apart.
At 31/12Z, the HWRF was initialized at 13.1N 51.5W - which could also become useless for the same reason. (Note that the initialization points are approximations.)
The 31/18Z NHC Tropical Suite was finally published using 13.5N 52.8W, so all of the model marbles are rolling on the right/east half.
To add a little spice to the soup, there is also another piece of energetic development near 18N 62.5W.
Given the luck that NHC (and us) have been suffering with this bi-polar system, I fully expect the right/east half to soon be designated as a TD. Twelve hours later the TD will fall completely apart and the left/west system will be designated a TS (humor intended).