The impact of extra tropical transition on hurricane risk in the Northeast US
Robert Muir-Wood, Risk Management Solutions Ltd., London, United Kingdom; and R. Dixon and A. Boissonnade
A strong correlation between central pressure and forward speed is found for hurricanes landfalling on Long Island and southern New England, as fastest storms avoid filling while passing over the cooler sea-surface temperatures to the north of Cape Hatteras. A strong correlation is also found between forward speed and extra-tropical transitioning, as a result of interactions with the jet. In consequence the deepest storms in the Northeast are also the most likely to have started transitioning.
Transitioning storms have different windfield structures to hurricanes and reduced maximum windspeeds at a given central pressure. From available meteorological and damage data it can be shown that all the most intense hurricanes to hit the Northeast over the past 200 years had started transitioning prior to landfall. Pre-existing ‘hurricane’ hazard models for the Northeast, covering extreme windspeeds, catastrophic insurance loss and storm surge heights may all need to be revisited, based on the appropriate inclusion of transitioning windfields.
Extended Abstract (112K)
Session 17D, tropical cyclone extratropical transition II
Friday, 7 May 2004, 10:15 AM-11:30 AM, Napoleon III Room
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