The strong low-pressure system in the middle of the Atlantic has broken free of the fronts that were attached to it, so it meets the criteria to become a named system. Officially it’s called Subtropical Storm Wanda.
On the satellite, it looks very much like a tropical storm. But in the upper atmosphere, there is a strong disturbance in the jet-stream flow, which is providing energy to the system. So it stays in the subtropical camp. In another day or so, that upper disturbance will move on, so Wanda could become substantially tropical before it moves north over cold water and becomes fully non-tropical again.
These are just meteorological technicalities, of course. Generally, there are structural difference between tropical and subtropical storms, but they both have the same strength winds. So if land is involved, the fact that it’s subtropical doesn’t change the impacts.
Subtropical storms first got named in the early 1970s, but the naming system kept changing before the National Hurricane Center decided to simplify things in 2002 by naming them the same way they do tropical storms. That’s been the system ever since.
Over by Africa, a broad area of disturbed weather has decent rotation but is not well organized. As it tracks generally toward the north over the next few days, it could develop into a tropical depression or tropical storm, at least briefly. Later in the week it will run into a bunch of dry air and colder ocean water. It won’t bother any land.
It would be super unusual for a system to develop that far east in the Atlantic this late in October. There is nothing comparable in the record book. The computer forecast models have been saying it’s possible, but not likely. The National Hurricane Center gives it a fairly low probability of happening.
Thirty years ago today, another freak storm was developing off the northeast U.S. coast. It came to be known as the Perfect Storm, and was made famous by the movie about the fishing boat the “Andrea Gail” that got caught in the stunningly high seas. An offshore buoy measured waves of 100 feet.
That storm had a more complicated meteorological history than Wanda, but was another example of a non-tropical system becoming subtropical and then eventually fully tropical. On October 31, 1991, the system developed a tropical storm in its center when it made its closest approach to the New Jersey and New York coast.
The next day, as it looped offshore, the tropical core developed into a hurricane with 75 mph winds. The National Hurricane Center decided not to name it at the time thinking it would be confusing to suddenly have a hurricane pop up offshore of the Northeast and New England. The fact was, the system was already an extremely powerful system doing damage along the coast without the meteorological distinction of having a hurricane at its center.
These days, of course, it would get a name. With social media and the continuous news coverage coming from all directions, it wouldn’t be a surprise in the same way.
This year, we still can’t rule out a surprise on our side of the Atlantic, but it’s unlikely. The weather pattern is forecast to be hostile to tropical development. As long as the cold fronts keep coming, we’re good.