Well developed circulation but missing the muscle (convection)

There is no doubt that if the environment around 93L were more moist, we would be looking at a strong tropical storm, soon to be hurricane. The circulation pattern of the system is very impressive. However, it lacks what it needs the most: deep convection.

Convection is what drives the heat engine of tropical cyclones. The air rises, condenses in to clouds, produces copious amounts of rain and this releases heat in to the atmosphere. Without sustained thunderstorm activity, or what we call convection, the process cannot move forward and the system will have a tough time strengthening.

Even in the face of all of this dry air down in the deep tropics, 93L does have a substantial circulation as seen clearly on satellite animations. If and when it can develop persistent convection, it will then intensify and easily become the next tropical depression and possibly tropical storm Bertha.

Right now, because it is fairly shallow in the atmosphere, it is moving almost due west with the low level flow. Should it acquire the convective activity that I mention, then it will likely begin to move more northward with time. This should place the would-be storm somewhere in the northeast Caribbean Sea over the weekend. Obviously, interests there need to monitor this situation closely.

Some of the computer guidance still holds on to the idea that 93L will eventually become a hurricane but I have my doubts. On the other hand, I also know how hard it is to predict intensity with tropical cyclones. The odds are not in favor of much strengthening but it is not wise to completely dismiss the idea that 93L could become at least a category one at some point.

Beyond the weekend, much will depend on how strong this becomes. Right now, the advanced global models show it weakening under strong southerly shear and thus is moves towards the southeast Bahamas. If it were to be stronger, it believe it would be further north but still fairly close to the Southeast U.S. to warrant some concern. It is tough to say as a lot can happen and again, we’re talking about many days in to the weather future. Sometimes, you just don’t know for sure.

Elsewhere in the Atlantic Basin, nothing is going on to be concerned with at the time. And in the east Pacific, there is plenty of activity to watch but it is all located well out away from Mexico, so no worries there.

I will post another update concerning 93L early this evening.

M. Sudduth 11:43 AM ET July 30

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