Updated at 9:30 a.m. Eastern: There are disturbances from the Caribbean to Africa that have some potential to organize in the next several days, and a couple merit watching because they might develop fairly close to land.
Potential Disturbance #1 is made up of two components. The northern part is a weak tropical disturbance we have been following for a few days as it has slowly migrated across the Caribbean. It’s hard to pick out because dry air has reduced it to just a few showers drifting west.
The southern part is a broad area of low pressure over the southern Caribbean, northwestern Colombia, and part of Central America. Over the next few days, it is possible that a combo disturbance could form in the western Caribbean Sea off the coast of Mexico’s Yucatán Peninsula.
There is a poor consensus on what’s going to happen among the various computer forecast models, so the National Hurricane Center is giving the combo system a slight chance of development. Everybody in the Yucatán should stay informed this week just in case.
Tropical Disturbance #2 is also a combo system. The northern cluster of thunderstorms was a disturbance that moved off Africa. The southern part was pulled from the south into the combo circulation. What happens in the future has a lot to do with how and where this system pulls itself together, and if it does – which part of the combo disturbance dominates. Or does it consolidate around a point in the center of the two clusters.
Currently, the southern cluster of storms seems to be the stronger feature. The beginnings of a circulation are evident. If that end up being the eventual center of an organized system, the consolidated circulation might track closer to the south side of the potential development area.
The National Hurricane Center is giving this system a good chance of developing into at least a tropical depression over the next 5 days. The only obvious deterrent to development would seem to be the abundant dry air to the north and in front of the system. Its future strength depends of how much of a moisture envelope it can wrap around the center.
Interests in the northeastern Caribbean islands should stay informed on developments with this system this week.
Disturbance #3 is still over Africa, but the National Hurricane Center has given it a slight chance of developing once it moves off the land and over the Atlantic. It appears to be a large system, so it will have a shot at holding off the dry air. Obviously, we’ll have a long time to watch this disturbance.
Disturbance #4 is an area of low pressure in the open ocean east of Bermuda. It has a slight chance of becoming a depression in the next few days before it is absorbed by a northern weather system. It’s unlikely to threaten any land area, even if it develops.
So things a picking up as expected with September around the corner. But the tropical Atlantic is still covered with more dry air than we would normally expect this time of year. While the general atmospheric pattern appears conducive for systems to develop, the dry air is keeping its foot on the brake – at least a bit.
It’s likely that some systems will tap into tropical moisture to the south, however, so we have to stay vigilant as we always are this time of year.