Paula's eyewall disintigrates as the storm weakens

Data from an Air Force Hurricane Hunter aircraft indicates that Hurricane Paula continues to weaken, and the storm may no longer be a hurricane. The latest 8:06am EDT center report found the pressure had risen to 1002 mb, and the aircraft saw top winds at their flight level of 10,000 feet of just 60 mph between 6am and 9am EDT. The Hurricane Hunters did not report the existence of an eyewall, and Cuban radar (Figure 1) indicates that the southern portion of the eyewall has collapsed, leaving Paula with just 1/3 of an eyewall. Paula is moving at 5 mph along the northern coast of Cuba, and is bringing heavy rains to the western portion of the island. Cabo San Antonio on the western tip of Cuba has picked up 4.85" of rain so far from Paula, and a wind gust of 60 mph was reported on the western tip of the island. Heavy rains have also hit the Florida Keys this morning, with Key West picking up 0.62" inches of rain in just 30 minutes from a heavy rain squall that ended at 7:30am EDT. Weather radar out of Key West (Figure 2) noted several regions offshore where Paula has dumped 5+ inches of rain. High wind shear due to strong upper-level winds of 30 knots out of the south are tearing Paula apart, and satellite imagery shows the storm has a lopsided appearance due to the shear, and the low-level center is almost exposed to view. Low level spiral banding is no longer as impressive, and the intensity of Paula's thunderstorms has waned significantly over the past few hours.


Figure 1. Radar image from the Pinar del Rio radar in Cuba at 8:30am EDT on October 14, 2010, showing the eye of Paula along the northwest coast of Cuba. Image credit: Cuban Institute of Meteorology.


Figure 2. Radar-estimated precipitation for Paula from the Key West radar.

Forecast for Paula
The models have come into better agreement on the future track of Paula, with the storm expected to move along the north coast of Cuba or just inland during the next three days. On this track, Paula will move over Cuba's capital, Havana, tonight and Friday morning, and bring heavy rains of 3 - 6 inches to the most populous region of the country. An extended period of time over mountainous Cuba will likely destroy a small storm like Paula within 48 hours, particularly since the storm will be under 30+ knots of wind shear. A path just off the coast will let Paula live a little longer, but not much longer. The models are pretty unanimous in showing that wind shear will pull Paula apart over the next two days regardless of whether or not the center stays over water. Tropical storm force winds extend out just 50 miles from Paula's center, so it is unlikely that the Florida Keys will experience sustained winds of 39+ mph. The 5am EDT wind probability product from NHC gives Key West a 40% chance of receiving tropical storm force winds; these odds are 83% for Havana. Havana may receive some minor wind damage from Paula, but it currently appears that heavy rain will be the major threat from Paula. The hurricane could easily dump more than ten inches over mountainous regions of Cuba, creating flooding hazards.


Figure 3. True color satellite image of Paula taken by the MODIS instrument on NASA's Aqua satellite at 2:35pm EDT October 13, 2010. Image credit: NASA.

Elsewhere in the tropics
The NOGAPS and GFS models are predicting the formation of a tropical depression 5 - 6 days from now, in the southern Caribbean off the coast of Nicaragua. The storm is predicted to move west-northwest over Nicaragua and Honduras (the NOGAPS model forecast) or northwards towards the Cayman Islands and Jamaica (the GFS model forecast.) The GFS model has been pretty reliable in forecasting the genesis of new tropical depressions this year, and the fact that we have two major models predicting the formation of a new Caribbean tropical depression next week is worth paying attention to.

In the Western Pacific, Tropical Storm Megi is nearing typhoon strength, and is predicted to intensify into a major typhoon that will strike the northern Philippine Island of Luzon on Sunday night or Monday morning.

Next update
I'll have an update this afternoon.

Jeff Masters