Subtropical Depression or Storm To Form In Next Couple Days

While organization has changed little today, development of the disturbance southeast of Bermuda is expected.

A "subtropical depression or 

storm is very likely to form during the next day or two", the National Hurricane Center (NHC) said this evening.

Satellite imagery shows a broad circulation of showers and clouds. 

A subtropical cyclone is a sort of combination of a tropical and extratropical cyclone. 

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The official definition is as follows: "A non-frontal low-pressure system that has characteristics of both tropical and extratropical cyclones. Like tropical cyclones, they are non-frontal, synoptic-scale cyclones that originate over tropical or subtropical waters, and have a closed surface wind circulation about a well-defined center. In addition, they have organized moderate to deep convection, but lack a central dense overcast. Unlike tropical cyclones, subtropical cyclones derive a significant proportion of their energy from baroclinic sources, and are generally cold-core in the upper troposphere, often being associated with an upper-level low or trough. In comparison to tropical cyclones, these systems generally have a radius of maximum winds occurring relatively far from the center (usually greater than 60 n mi), and generally have a less symmetric wind field and distribution of convection."

(click here to view this and other definitions) 
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Basically, the subtropical cyclone has a circulation around a defined center, like the tropical cyclone. 

However, it is less symmetrical. In addition, the atmospheric components of it are not like a tropical cyclone.

Regardless, this system is expected to continue to meander to the east and southeast of Bermuda for the next several days. 

If it reaches subtropical storm status, it will be named Epsilon. 

In the southwestern Caribbean, a low pressure system is still expected to form in the next few days, and gradual development is possible thereafter.