TD14 forms in northwest Caribbean.

The area of disturbed weather that was in the southwest Caribbean late
last week and during the weekend has drifted north and become much
better organized, exactly how the models had predicted five days ago
(they're on a roll this season).  As I watched the system over the
weekend, it was remarkable to watch in real-time a tropical cyclone
develop out of nothing more than a broad area of convection.  Hour by
hour, the convection became more centralized, a mid-level circulation
developed, deeper convection, and finally a low-level circulation was
obvious on visible imagery this morning (I'm sure I'm not the ONLY one
who woke up excitedly to check the first available VIS images for a
low-level circulation...).

At 15Z today, TD14 was at 17.8N 83.0W and tracking N at 10kts. 
Intensity is 25kts and 1009mb, but is expected to quickly reach TS
status today (and would become the thirteenth named storm of the season,
Marco).  A Tropical Storm Warning is in effect for the Cayman Islands,
Isle of Youth, and central Cuba, and a Tropical Storm Watch is in effect
for southern FL from Golden Beach to Key West.

The forecast track is generally N-NNE, allowing the center to pass east
of the Florida peninsula, but admitedly, the distance at which it's
forecast to pass by at is within the forecast error (hence the TS Watch
for southern FL).  There is a very deep trough digging into the Gulf of
Mexico which will be the primary steering mechanism for this storm, so
it's movement and amplitude will play a huge role in track forecasting. 
The GFDL model is very insistent on making this a strong storm, hitting
Cuba as a 92kt CAT2 hurricane, then the Bahamas as a 103kt CAT3
hurricane.  The SSTs in its path would support a major hurricane, it
will just be a matter of how Cuba affects it and how much shear the
trough will introduce.

Please visit my tropical Atlantic headquarters.