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.