Paloma nears Caymans, approaches Cat. 2 status

Hurricane Paloma is continuing to strengthen as it approaches the Cayman Islands. Officially, the intensity is 90 mph as of 1:00 PM EST, and it’s possible we could see Paloma upgraded to Category 2 status at the next advisory, given what Dr. Jeff Masters writes:

Between 1 pm and 3 pm EST, an Air Force Hurricane Hunter aircraft dropped two sondes in the northwest eyewall of Paloma, and found winds of 90 and 97 mph at the surface form these sondes. The threshold of Category 2 strength is 96 mph.

Dr. Masters also notes that Paloma is showing some fascinating structural features, which could portend either imminent strengthening, an impending eyewall replacement cycle (which would tend to temporarily retard intensification), or perhaps both: a brief rapid-deepening phase, followed by an ERC. Masters writes:

The central pressure of Paloma is dropping at about 1-2 mb per hour. The Hurricane Hunters noted that Paloma appears to be forming a second eyewall concentric with the main eyewall, and there is also evidence of this on visible satellite loops. There was also a gap noted in the SSW side of the eyewall by the Hurricane Hunters, and the storm is undergoing some substantial structural changes. Formation of a secondary concentric eyewall will ordinarily slow down intensification of a hurricane, but is also spreads out the highest winds over a larger area. Recent infrared imagery shows that the eye has warmed, indicating strengthening. Some very impressive thunderstorms with high, cold tops are firing up at several points in the eyewall, also indicative of strengthening. These thunderstorms may be “hot towers”, which are often observed when a hurricane is embarking upon a major intensification phase. 

Although forecasters don’t have the ability to predict rapid intensification bursts or eyewall replacement cycles with any degree of precision, conditions are generally favorable for strengthening, and thus Paloma is expected to continue getting better organized for the next 24 hours or so. Officially, the storm is forecast to peak as a low-end Category 3 hurricane, with peak winds of 115 mph, tomorrow morning.

Then, wind shear is forecast to increase markedly, and thus Paloma will probably weaken back to a Cat. 1 before landfall in Cuba overnight Saturday night. After crossing Cuba, Paloma may “lose vertical coherence,” according to the 10am NHC discussion; in any event, it will continue to degrade rapidly, and will eventually become extratropical.

Meanwhile, weatherblogger Alan Sullivan is now aboard the cruise ship Noordam, preparing to sail in Paloma’s general direction. He writes:

There seems something apt about sailing into a hurricane on a luxurious cruise ship in such times. Paloma continues to strengthen steadily. In the stronger scenario we will experience tropical storm conditions at sea tomorrow, while the center of Paloma runs onto Cuba’s south coast. In the weaker scenario, we hit squally thunderstorms as upper energy shears northeast while Paloma fades in the Caribbean.