I am not a weather 'expert', but I will give it a shot. An anticyclone is an area of high pressure in the upper atmosphere. To have a strong tropical system requires (among other things) a SURFACE area of LOW pressure and an UPPER area of high pressure. It has to do with moving heat from the ocean surface upward and developing strong convection. Many tropical systems have well developed lows at the surface, but don't have good high pressure aloft to help develop a stronger system. This one has the high pressure above, but lacks a strong low at the surface at this point. I may get corrected on the fine points, but that is the way I have been taught this (PLEASE correct me if I am wrong....I HATE to be wrong

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