TD 27 still hanging on

Tropical Depression 27 continues to struggle against high wind shear generated by strong upper-level westerly winds. The storm has a small area of deep convection over the center, and a very small and weak circulation center. The circulation was too small to be resolved by the QuikSCAT satellite in its pass at 5:30 am this morning. Wind shear has held steady at about the same level we've seen the past two days, 20 knots. This shear is still high enough that there remains a 10% chance that the depression will dissipate within the next 24 hours. If the storm can survive until then, the shear will decrease enough to allow TD 27 to strengthen into a tropical storm and remain in a threat to the Caribbean for the rest of the week.

The eventual intensity of TD 27 is still highly uncertain. If TD 27 can position itself under an upper-level anticyclone that is expected to develop by Wednesday over the central Carribean, the storm has a chance to attain hurricane status. Ocean temperatures are 28-29C--plenty warm enough to allow a hurricane to form. However, the GFDL model is no longer predicting that this will be a major hurricane--it forecasts that TD 27 will strike Honduras as a Category 1 hurricane late in the week. This may be a result of the fact that the models are now forecasting increasing wind shear over the western Caribbean starting Friday. The other major intensity model, the SHIPS model, forecasts a strong tropical storm by the end of the week.

The computer models continue to agree that TD 27 will track westward over the Caribbean for the next five days, under the steering of a strong ridge of high pressure. By the end of the week, the storm should slow down, as a trough of low pressure to the north breaks down the ridge. This trough may be strong enough to force TD 27 northwards, where it would get caught in the westerly winds prevailing over Cuba and get recurved out to sea. This solution is favored by the Canadian model. The other models keep the ridge strong enough so that TD 27 remains over the ocean, or makes landfall in Honduras late in the week. I still believe Honduras is most at risk from this storm, followed by Nicaragua, Cuba, Jamaica, the Cayman Islands, and the Bahamas.

The Hurricane Hunters are scheduled to make their first flight into TD 27 this afternoon at about 2 pm EST.

This will be my final blog for nine days, I am headed to Puerto Rico for vacation. I hope not to be on the front lines for the next tropical system, but it certainly is possible! This hurricane season could well extend into early December, as happened in the 2003 hurricane season. I will be back to blogging on November 25 to talk about what remains of hurricane season, summarize this amazing Hurricane Season of 2005, and speculate on next year's hurricane season. Be sure to catch the PBS NOVA and Frontline shows on Hurricane Katrina, airing Tuesday Nov. 22 and 8 pm and 9 pm, I hope to talk about that show, as well.

While I am gone, meteorologists John Celenza and Shaun Tanner of the Weather Underground will be updating my blog on all the latest about TD 27.

Jeff Masters