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Paula continuing to weaken

By: Dr. Jeff Masters, 7:53 PM GMT on October 14, 2010

Data from an Air Force Hurricane Hunter aircraft indicates that Tropical Storm Paula continues to weaken. The aircraft's latest center penetration at 3:08pm EDT found top winds at their flight level of 10,000 feet of just 55 mph in the eyewall. The SFMR instrument saw surface winds near 65 mph. The eyewall of Paula has collapsed, and satellite imagery shows the storm has a lopsided appearance due to wind shear. The low-level center is almost exposed to view, the classic satellite signature of a storm under high wind shear. Since the high wind shear affecting Paula is pushing most of the storm's heavy thunderstorms to the north, Cuba is receiving very little rain from the storm. Havana has reported two brief rain squalls from Paula, and top sustained winds of just 20 mph. Sporadic heavy rains are affecting the Florida Keys today, with Key West picking up 1.01" inches of rain thus far. Weather radar out of Key West (Figure 2) noted several regions offshore where Paula has dumped 5+ inches of rain.

Figure 1. Radar image from the Pinar del Rio radar in Cuba at 3:15pm EDT on October 14, 2010, showing that Paula is now very disorganized. Image credit: Cuban Institute of Meteorology.

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

Forecast for Paula
The models continue to predict that Paula will move along the north coast of Cuba or just inland during the next two days. On this track, Paula will move over Cuba's capital, Havana, tonight and Friday morning. An extended period of time over mountainous Cuba will likely destroy a small storm like Paula by Friday night, particularly since the storm will be under 30+ knots of wind shear. The models are pretty unanimous in showing that wind shear will pull Paula apart over the next day regardless of whether or not the center stays over water. Tropical storm force winds extend out just 45 miles to the north of Paula's center, so it is unlikely that the Florida Keys will experience sustained winds of 39+ mph. The 11am EDT wind probability product from NHC gives Key West a 21% chance of receiving tropical storm force winds; these odds are 70% for Havana. Havana may receive some minor wind damage from Paula, and there may be some minor flooding problems in the mountainous regions of Cuba.

Elsewhere in the tropics
The latest 8am EDT (12Z) NOGAPS and GFS model runs continue to predict the formation of a tropical depression 4 - 5 days from now, in the southern Caribbean off the coast of Nicaragua. The storm is predicted to move northwest or northwards towards the Cayman Islands and Jamaica, once it forms. 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 Friday morning.

Jeff Masters


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