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Franklin, and 3 other tropical waves

By: Dr. Jeff Masters, 7:54 PM GMT on July 22, 2005

I don't have much to add on Franklin; it is gradually strengthening and beginning to resemble a real tropical storm as it moves away from the shear that was hurting it earlier today. It's still anyone's guess where Franklin will go, and I won't speculate on this more until later. It is interesting to watch the storm's progress on Melbourne Florida's long range radar.

The wave in the Caribbean that was shearing Franklin is now moving over the Yucatan, and appears primed to develop. Only the presence of the Yucatan is keeping it from developing right now, and once it moves into the Gulf tomorrow, I believe we will have another tropical depression.

A small disturbance at 10N 53W has been attracting the attention of several of the people posting comments. This tropical wave has several things going for it--a decent upper-level anitcyclone on top, low wind shear overhead (5 - 10 kt), and warm ocean waters ahead of it. The wave has one big negative--the steering flow is going to carry it into Venezuela. The steering flow does bend more WNW once the disturbance reaches South America, so it is possible that the wave could gain enough latitude to not be totally destroyed by interaction with land. The surface wind field under the disturbance is not well-developed--the QuikSCAT winds show a uniform east find flow under the disturbance, with not much of a hint of a wind shift associated with it. It is possible that this wave could develop into a tropical depression in two days or so, but I think the interaction with South America will likely prevent that from happening.



A tropical wave in the middle of the Atlantic at 11N 35W has some promise; it is further north and less likely to interact with South America. Just north of that tropical wave is a huge low pressure area loaded with African dust. This low has so much dry air and dust in it, that convection has been able to develop in association with it. It is not expected to develop into a tropical depression. This is an unusually large low pressure system for this part of the Atlantic, and will sharply reduce visibilites in the Caribbean islands over the next week when it blows in with its load of Saharan dust. One can see the greyish load of African dust it carries covering nearly half of the tropical Atlantic between the Lesser Antilles and Africa. Residents of the Southeastern U.S. may see the dust from this system color their sunsets late next week.

Jeff Masters

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