Gustav goes tropical, and scrapes the NC coast.

Monday evening into Tuesday morning was quite the treat to anyone
carefully watching Gustav's convective patterns (as I'm sure most of you
were...).  He made the transition from subtropical to tropical, and even
without data on low-level wind distribution or vertical temperature
distribution, one could see the storm contract, pulling the deep
convection over the center, and forming feeder bands.  Combined WITH
knowledge from aircraft and AMSU, we know that the surface winds were
getting stronger toward the center of circulation and that a warm core
aloft was becoming established.  In short, he's now Tropical Storm
Gustav (as of 12Z today).

The intensity has been increasing, now up to 50kts and 986mb.  The winds
seem weak for a pressure that low, but it's intensifying and the two
fields are most likely not in equilibrium.  Now on to the track... he is
moving north, which means the westward advance toward mainland NC has
ceased.  However, Tropical Storm Warnings are in effect for most of the
NC and VA coasts.  The center of the strom should pass over or very near
Cape Hatteras, NC.  He's about at his closest approach now (3pm
Eastern), and after this, will rapidly accelerate out ot sea in advance
of a trough.

The 18Z advisory places TS Gustav at 34.8N 75.8W and tracking N at
9kts.  As mentioned earlier, the intensity is 50kts and 986mb.  With the
aid of baroclinic enhancement, Gustav should reach hurricane strength
late tonight or by midday Wednesday.  

The tropical wave in the central Atlantic has become much less defined
now, and is in high shear, so it will not be an area of concern for a
while.

NHC is monitoring the west central Gulf of Mexico for possible
development of a Low.  Some models hint at something there as well. 
Right now, it's a large area of disturbed weather with slightly lowered
pressures.  Given the somewhat favorable conditions though, it's not
unreasonable to expect development from it over the next few days.

FYI, today is the climatological peak of activity for the Atlantic
hurricane season, yet we still have not had a hurricane.  Recall last
year the first hurricane formed on Sept 8 and then there were nine of
them from that date through the end of November!

Please visit my tropical Atlantic headquarters.