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Leslie downgraded to tropical storm, not expected to affect US

MIAMI – The "area to watch" in the Caribbean continues to attract our attention. Meanwhile, Tropical Storm Leslie is now below hurricane strength in the middle of the Atlantic Ocean and not going anywhere fast.

The "area to watch" is showing a bit more organization, but it is still embedded in a large area of low pressure spread across Central America and into the Caribbean. The budding circulation that we are following is near the east coast of Honduras. 

The models show the system drifting toward the Yucatan Peninsula of Mexico through the weekend. The upper-level winds are forecast to be increasingly hostile to any quick development during that time, so significant organization or strengthening is not expected.

Next week, however, the system may find a pocket of favorable upper winds ahead of a strong dip in the jet stream when the system reaches the southwestern Gulf of Mexico. The jet-stream dip will bring a strong steering flow over the Gulf that could push the system toward the northern Gulf Coast.  

There are a number of unknowns in this scenario, including whether the circulation survives over the next few days so that there is something organized to be pushed north. Also, it appears the pocket of favorable upper winds will be small, so the system would have to thread a needle to avoid the hostile conditions which could rip it apart nearby. It would also have to avoid those strong upper-level winds to intensify into a significant storm, assuming the upper-air pattern develops as forecast.

In any case, nothing is going to happen quickly. For now, we will watch to see how the system organizes, if it does, between now and the first of the week.  

No matter what happens, the disturbance does not appear to be a direct threat to South Florida, although the overall weather pattern favors a general return of tropical moisture over the southern Florida peninsula next week. This is in part related to the strong jet stream dip and the low pressure/"area to watch" developing in the Gulf.  Both will have the effect of pulling tropical moisture north.

Tropical Storm Leslie is now estimated to have top winds of 65 mph. It is still chugging along in the middle of the Atlantic, slowly moving in the direction of Europe. It is not expected to threaten land in the next week, if at all.

Otherwise, a couple of small pieces of the upper air system that is loosely part of Tropical Storm Leslie are forecast by the computer forecast models to break off and move in the direction of Florida next week. If that happens, the main effect of these weak disturbances will likely be to further enhance the rain that is already expected due to the significant increase in tropical moisture over the state. There are a lot of potential moving parts, so for now just expect more rain next week in South Florida.


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