While things are fairly quiet across the Atlantic, Caribbean and Gulf, it does look like things will probably start becoming much more active once we head towards mid-August or so.
An upward motion pulse of the Madden Julian Oscillation, which promotes rising air and storminess is currently moving across the central and eastern Pacific. It is expected that this upward motion pulse of the Madden Julian Oscillation will find its way into the Atlantic starting next week and with it, there is likely to be increased chances for tropical development.
Because of this, there are some areas of interest that I am keeping an eye on:
The First Area That I’m Watching Is near and just offshore of the US Southeast coast. A frontal boundary is expected to stall from the Carolinas eastward into the western North Atlantic by this weekend. Several low pressure systems are likely to form along this front and move east-northeastward.
My guess is that these low pressure systems will remain non-tropical in nature and will remain linked to the frontal boundary. Because of this, the tropical development chances near and offshore of the southeast coast of the United States are very low. That said, it is something that I will be keeping an eye on, just in case.
The Second Item That I’m Keeping An Eye On Is a couple of tropical waves over the central and eastern Tropical Atlantic. One wave is located near 45 West Longitude and the second wave is located near 30 West Longitude. There is very little convection occurring with either wave and development is not expected anytime soon.
It is anticipated that these two waves will merge as they move west-northwestward and pass over the Leeward Islands by about Friday into Saturday. While development is not expected, this wave may bring some squally weather to the Leeward Islands during Friday into Saturday.
Beyond this, it is expected that this tropical wave will reach the Bahamas by early next week where there is some minor interest from the model guidance of it trying to develop. The UKMET model has the most interest in forecasting development from this wave as it shows it becoming a depression in the northwestern Bahamas by early next week and then head for the Southeastern United States during the middle and later parts of next week as a tropical storm.
Other than that, just the European ensemble model guidance does have a couple of members that hint at development later next week north of the Bahamas.
For now, I think the chances of development between the Bahamas and the US Southeast Coast next week are pretty low (less than a 25 percent chance). That being said, this tropical wave will be monitored very closely in the coming days, in case it does try to develop.
The Third Item That I Will Be Keeping A Close Eye On Are the follow up tropical waves that will be pushing off of the coast of Africa over the next couple of weeks. As I mentioned earlier in this discussion, an upward motion pulse of the Madden Julian Oscillation will be pushing into the Atlantic Basin starting next week and will remain in place through mid-August. This will allow for conditions to be more conducive for any westward moving tropical waves to develop.
The longer range model guidance are already seeing these expected changes in the tropics by forecasting increased chances for tropical development over the central and eastern Tropical Atlantic starting later next week and continuing through the week of August 11. In fact, the longer range European ensemble model is forecasting that the week of August 11 could be particularly active with almost double the normal activity for that particular week & this all could come from the wave that the models are developing.
So, which tropical wave is the model guidance honing in on as a candidate for likely development? In trying to track the energy that leads to the development in the models backwards, it seems it’s the tropical wave that’s still located over east-central Africa near about 10-15 East Longitude. Guidance seems to suggest this wave will push off of the coast of Africa into the far eastern Tropical Atlantic early next week and then reach the Lesser Antilles late next week or next weekend. Beyond this, longer range guidance hints at this wave being in the vicinity of the Bahamas during the first half of the week of August 11.
Because of this, I do think that this particular tropical wave that’s still located over east-central Africa will need to be watched very closely as we get into next week through next weekend as it heads westward across the eastern and central Tropical Atlantic towards the Lesser Antilles.
The next tropical weather discussion will be issued on Friday.