Category 4 Paloma pounds the Cayman Islands, heads to Cuba

Hurricane Paloma exploded into a extremely dangerous Category 4 hurricane with 140 mph winds last night as it hammered the Cayman Islands. Paloma now ranks as the second most powerful November hurricane on record, and stands poised to deliver Cuba a devastating blow tonight. The latest data from the Hurricane Hunters and satellites indicate that Paloma has probably peaked in strength, and will slowly weaken today. Visible satellite loops show that strong upper-level winds from the west are starting to restrict the upper-level outflow on the west side of the storm, though the hurricane still has impressive organization and a well-formed eye. Infrared satellite loops show that the hurricane's cloud tops are warming, indicating weakening. The latest Hurricane Hunter mission departed the storm at 6:30 am EST, and the next mission should arrive about 1 pm EST. Radar from Camaguey, Cuba shows no evidence that the shear has weakened the eyewall of Paloma. There is evidence to suggest the hurricane may be forming a concentric eyewall, which would act to spread the hurricane's winds over a larger area and increase the region affected by a high storm surge.

Paloma's impact on the Cayman Islands
A strong trough of low pressure over the U.S. East Coast began pulling Paloma to the northeast late last night. Paloma's turn to the northeast came earlier than originally forecast, much to the advantage of Grand Cayman Island, but much to the detriment of Little Cayman and Cayman Brac islands. The earlier turn also allowed Paloma to stay just south of the higher levels of wind shear that would have weakened the hurricane. The eye of Paloma passed just east of Grand Cayman, and the strongest eyewall winds barely missed the island. Winds at the Grand Cayman airport on the west end of the island peaked out at 46 mph gusting to 62 mph at 7 pm EST, though winds were close to hurricane force on the east end of the island. Preliminary news reports indicate that the island suffered some flooding, but no major wind damage or storm surge.

Little Cayman and Cayman Brac were not so lucky. There are reports of heavy damage on the islands, which received a long battering by the northern eyewall of Paloma. Cayman Brac, which lies a little farther south than Little Cayman, took a direct hit, with the calm of the eye lasting several hours. Ironically, today is the anniversary of the deadly 1932 hurricane that flattened Cayman Brac, killing 69 people.


Figure 1. Visible satellite image of Paloma at 9 am EST Saturday November 8, 2008. Image credit: NASA/GSFC.

The forecast
A strong trough of low pressure over the U.S. East Coast is pulling Paloma to the northeast, and this trough should continue to pull the storm across Cuba tonight and into the Bahama Islands on Sunday. Wind shear is a high 25 knots, and is expected to increase to 35 knots tonight and 45 knots on Sunday. Paloma should not be able to intensify any further under this kind of shear, though it may be able to hold on to its current intensity until tonight, since it will take some time for the increasing shear to be able to penetrate into the heart of such a powerful, well-formed vortex and disrupt it. Landfall tonight in Cuba as a Category 3 hurricane with 115 mph winds is a good bet, which is the forecast of the latest 12Z SHIPS intensity model. The HWRF model foresees a Catgeory 2 hurricane with 110 mph winds at landfall in Cuba, while the GFDL calls for a Category 1 hurricane with 75 mph winds. Regardless of its intensity at landfall, Paloma will bring an exceptionally high storm surge of 17-23 feet to the coast of Cuba, since the hurricane has set a large volume of ocean in motion with its Category 4 winds. There is also a large area of shallow water just offshore the south coast of Cuba that will allow the storm surge to pile up to a great height. Cuba will take a terrific pounding from Paloma, and damage from the triple crunchings delivered by Hurricanes Gustav, Ike, and Paloma will make 2008 the worst hurricane season in Cuban history. The latest H*Wind analysis of Integrated Kinetic Energy from NOAA's Hurricane Research Division puts the potential wind damage at 2.6 on a scale of 1 to 6, and the potential storm surge damage at 2.5 on a scale of 1 to 6. The relatively low storm surge potential is misleading, since Paloma is headed toward a portion of the Cuban coast that is highly prone to storm surge.

Passage over Cuba combined with extremely high values of wind shear should tear apart Paloma before it reaches the central and southeastern Bahamas. The HWRF, GFDL, and SHIPS intensity models are all calling for Paloma to dissipate or be a tropical storm or tropical depression by the time it arrives in the Bahamas on Sunday, and this is a reasonable forecast. Paloma has virtually no chance of surviving long enough to threaten Florida.

Links to follow
Radar from Camaguey, Cuba
Santa Cruz del Sur, Cuba weather

A new record for the hurricane season of 2008
This year is now the only hurricane season on record in the Atlantic that has featured major hurricanes in five separate months. The only year to feature major hurricanes in four separate months was 2005, and many years have had major hurricanes in three separate months. This year's record-setting fivesome were Hurricane Bertha in July, Hurricane Gustav in August, Hurricane Ike in September, Hurricane Omar in October, and Hurricane Paloma in November.

Paloma is now the second strongest November hurricane on record in the Atlantic. Hurricane Lenny of 1999, a Category 4 hurricane with 155 mph winds, was the strongest November hurricane on record. Paloma shares second place with Hurricane Michelle of 2001 (Cat 4, 140 mph) and Hurricane Greta of 1956 (Cat 4, 140 mph).

I'll have an update Sunday, possibly not until the afternoon.

Jeff Masters