ReAdvisory Issues Analysis of Fay as she Approaches Florida Mainland

In a report issued Aug. 17, ReAdvisory, a modeling and risk assessment service of reinsurer Carvill America Inc., said Tropical Storm Fay became the sixth named storm of the 2008 hurricane season early on the evening of Aug. 15.

Fay formed from a tropical wave that had shown the potential for intensification since it left the African coast over a week prior, according to the report.

Since becoming a tropical storm Fay has tracked across Hispaniola and into the Caribbean south of Cuba. Paralleling the southern Cuban coast, Fay’s track has gradually been acquiring a northern component and was predicted to hit the northern coast of Cuba early on Aug. 16 between Cienfuegos and Pinar Del Rio provinces. Officials issued tropical storm warnings for most of Cuba’s northern provinces (including Ciudad Habana) as well as the Cayman Islands.

At 11 a.m. EDT on Aug. 17, the National Hurricane Center estimated Fay to be roughly 48 hours from landfall along the coast of Florida. Models show that Fay will turn north as it reacts to a weakening in the frontal system over the U.S. Gulf coast. There is, however, marked divergence in the model forecasts as to the actual track Fay will take. One set of model runs take Fay across the western Keys, into the Florida coast near Ft Myers, then across Florida, into the Atlantic and a final landfall along the Carolina coast.

Another set of model forecasts give Fay a more westerly track taking the storm over the open Gulf of Mexico to an eventual landfall along the Florida Panhandle in the Pensacola/Panama City region. The fact that the models are have such a difference so close to landfall is a cause for concern and does not allow a reasoned estimate of the landfall location beyond saying that the entire Gulf coast of Florida is at risk.

The intensity forecast for Fay is highly dependent on the track taken by the storm. In general wind shear is low (approx. 10 knots) and a slight but not significant impediment on the storm. In the positive column, the water temperature in the northern Caribbean Sea and eastern Gulf is very high. There is plenty of water vapor in the atmosphere and Fay is sitting under a good outflow pattern.

Interaction with the Cuban mainland was predicted to weaken and disrupt the storm but it will likely remain a tropical storm when it enters the Gulf. At that point, the intensity forecast for Fay will be dependent on the track – the longer it can stay at sea, the stronger the storm will become. A landfall in the Ft. Myers area will likely see Fay as a borderline tropical storm/Category 1 hurricane. Landfall near Tampa would likely see Fay as a Cat 1. A landfall along the Panhandle has the small (but not insignificant) chance that Fay could become a major hurricane (Cat 3).

The NHC has issued hurricane watches for the Florida Gulf coast south of Tampa and tropical storms warnings for the Florida Keys and extreme southern Florida. If Fay takes a more westerly track, warnings and watches are likely to issued in the next 24 hours for the rest of the Florida coast.

The hurricane most similar to Fay in the last few years is Hurricane Charley in 2004. Charley made landfall along a similar part of the Cuban coast and put on an impressive burst of intensification to make landfall near Ft. Myers. Fay is unlikely to be a repeat of Charley, however. When Charley hit Cuba it was already a Cat 3; Fay was a strong tropical storm at Cuba. If Fay takes a western track towards the Panhandle, it has the potential to look similar to either Ivan (2004) or Dennis (2005).

Source: ReAdvisory and Carvill America Inc.