Fay survives passage over Hispaniola, takes aim at Cuba

By: Dr. Jeff Masters , 3:54 PM GMT on August 16, 2008

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Tropical Storm Fay has completed a traverse of the length of the island of Hispaniola and survived intact. Although Fay's top winds are still rated at 45 mph, the storm did suffer from the passage, and the intensity and areal coverage of the storm's heavy thunderstorm activity are not as great as last night. However, the center is now over water, in the channel between Haiti and Cuba, and Fay is already beginning to show signs of regeneration. Visible satellite loops show an increase in heavy thunderstorm activity in all quadrants of the storm, and Haiti and the Dominican Republic have not see the last of Fay's wrath. Heavy rain is of particular concern today over Haiti, where any heavy rain is always a danger to cause major loss of life, due to the lack of vegetation on that nation's deforested mountainsides. Heavy rains will spread over Jamaica and eastern Cuba this afternoon, and over the Cayman Islands and central Cuba tonight. Damaging winds should not be a significant problem in Jamaica, Haiti, and the Cayman Islands, but are a concern in Cuba.

Fay may already have claimed its first victims. At least 23 people are dead due to a head-on collision between two buses at 8 am Friday near the town of La Romana in the eastern tip of the Dominican Republic. It was raining heavily at the time of the accident, due to the advancing rains of Fay. Fay's rains also washed out a bridge in the region and caused flooding in six provinces which displaced 2300 people and damaged 446 homes, according to DiarioLibre.com. About six inches of rain fell in a 12-hour period ending at 2 am EDT Saturday over the southeastern Dominican Republic, according to satellite estimates.


Figure 1. Geography of Cuba, with NHC forecast track overlaid. Image credit: Center for Genetic Engineering and Biotechnology (CIGB) of Havana, Cuba

The forecast for Fay
Wind shear is a low 10 knots over Fay, and is expected to remain below 10 knots for the remainder of Fay's life. An upper-level anticyclone has set up on top of Fay, allowing the air lifted from the surface by the storm's heavy thunderstorms to be efficiently spewed out to the sides, ventilating the storm and promoting even more intense thunderstorm activity. This favorable upper-level wind environment is expected to last at least through Sunday.

The latest (2 am EDT) model runs have shifted the track for Fay somewhat to the east, increasing the danger to the southwest coast of Florida near Ft. Myers. However, the models still show considerable spread, with one model (the NOGAPS) taking Fay to the Alabama coast, and several other foreseeing a strike near Miami. Fay will be passing near two areas of high mountains in Cuba (Figure 1). Fay may clip the rugged southeast tip of the island Sunday morning, then traverse the width of Cuba Sunday night over another region of high mountains. Both of these encounters may force sudden jumps in the center position as the storm reforms closer to its heaviest thunderstorm activity. As a result, the track forecast for Fay has a high level of uncertainty.

Fay's future strength when it hits the U.S. depends critically upon how much strengthening occurs today. Fay will be traversing the highest heat content waters in the entire Atlantic Ocean today, so there is the potential for the storm to reach Category 1 hurricane status before crossing Cuba Sunday night. If Fay does hit South Florida, the storm is likely to be a tropical storm or Category 1 hurricane, since it will not have enough time over water to reorganize much. A strike further up the coast will likely result in a stronger Fay at landfall, with a Category 3 storm not out of the question (20% chance).


Figure 1. Tropical Cyclone Heat Potential for Fay. Fay will be traversing over the highest heat content waters in the entire Atlantic today. Values of the Tropical Cyclone Heat Potential in excess of 80-90 are often associated with rapid intensification of hurricanes. Image credit: NOAA/CIRA/RAMMB.

Links to follow
Wundermap for Cuba/Haiti
Gran Piedra, Cuba radar
Jamaica radar
Key West, FL weather

I'll have an update Saturday night by 9 pm EDT, and present the sea turtle forecast for Fay's track.

Jeff Masters

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About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.