Oct 7, 2011

DAY 128

Philippe has become our 5th hurricane of the 2011 season. He has been gradually strengthening throughout the day and now has maximum sustained winds of 90 mph and a central pressure of 976 mb. This has occurred despite being under some relatively strong shear. The difference has been the direction of that shear. While Philippe was heading west, it was his motion plus the head wind to produce the shear number. But now he is going with the grain, so it's his motion subtracted from a tail wind to produce what is still a high shear number, but without the detrimental effects on Philippe's structure.

(Hurricane Philippe)
Hurricane Philippe started to display some classic tropical cyclone features. He has some nice curved feeder bands, and even a notch in the center which is an eye trying to form. But there is also a lot of clutter around him from a frontal boundary that has come in contact with him. It is that front that will shove Philippe out into the north Atlantic. He will have one more day at hurricane strength before being swept away. Philippe's got a shot at Cat 2, but that's about it. There just isn't enough time for him to pull any Ophelia-like surprises and make it to a major hurricane. The microwave image below shows a very small eye-wall that is not quite enclosed by the really cool cloud tops marked in red. Still a long way from a major hurricane.

(Hurricane Philippe Microwave Image)

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