Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.
By: Dr. Jeff Masters , 3:38 PM GMT on August 23, 2005
The remains of TD 10 continue to fester over the Bahama Islands, and the clouds have taken on that decidedly messy pattern associated with a tropical depression in the formative stages. An exposed low level circulation center is apparent in both visible satellite imagery and winds from the Quikscat satellite. The circulation was north of eastern Cuba and south of the central Bahama Islands, near 22.5N, 76W at 11am EDT. Deep convection is all east of the low level circulation center, and Quickscat winds as high as 30 knots were measured in this area. Observation stations in the vicinity are sparse, and I have not yet seen any pressure falls in those stations close to the system.
The environment surrounding the system is good but not ideal. Water temperatures are quite warm--about 29C, and closer to 31C near the western Bahamas. However, wind shear levels have been increasing somewhat over the past 12 hours and are about 10 - 15 knots (5 -10 knots would be much better.) A small upper-level low just north of the system may act bring some dry air into the system and hamper any upper-level outflow that tries to develop. Another possible problem is the presence of the large landmass of Cuba to the south, which may disrupt the system's circulation if it tracks more westerly. I expect the storm to continue to torment us by very slowly continuing to organize as it moves towards Florida.
The system appears to be tracking west-northwest at a very slow 5 to 10 mph, and the latest "early guidance" shows the storm moving more northwesterly towards Florida over the next few days. However, steering currents are weak and more westerly motion towards Cuba or the Straights of Florida would not be a surprise. Some of the computer models such as the Canadian model strengthen the system into a hurricane over the Gulf of Mexico later in the week. Some very warm water (32C, or almost 90F) lies off the west coast of Florida that model believes will fuel the storm into a hurricane. The GFS model makes the system a weak tropical storm that moves over Florida by Friday, then keeps the system a weak tropical storm as it recurves past the Carolinas. If the system does become a tropical storm, it is unlikely the upper level winds will allow intensification into a hurricane for at least the next three days. By that time, it's anybody's guess what might happen. One thing is for sure--the remains of TD 10 will be a around for a lot longer, they're going nowhere very fast. I expect I'll still be talking about this system next week!
A Hurricane Hunter aircraft is scheduled to visit the remains of TD 10 at 5pm this afternoon to see if a new tropical depression has formed. If so, it will be interesting to see if they call it TD 10 again, since the NHC discussions have been refering to this system as "possibly the remnants of TD 10".
African Tropical Waves
The large tropical wave 700 miles west of the Cape Verde Islands has gained some deep convection on its east side since yesterday, but has struggled to maintain its convection in the face of some increasing wind shear this morning. The system is also battling some dry air to its norhtwest that is getting entrained into the center. This system could still become a depression in a day or two as it moves west to west-northwest. Global models forecast that this storm will recurve before it threatens any land.
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