After a very quiet August in the Atlantic, we're starting to see a bit more "life" in the African wave train, which is not surprising given how close we are getting to the midpoint of the Atlantic hurricane season. The dry plume that dominated the eastern parts of the Atlantic Ocean, which suppressed tropical development or, when storms did form (Dorian, Erin), quickly zapped them of strength, is starting to wane somewhat. Modeling from the GFS and other guidance shows a more favorable regime for tropical development in the Atlantic over the next two weeks, thanks to the propagation of the MJO into 'phase 1'.
If you want a bit of a technical MJO discussion, check this out as a starting point. While the MJO is the dominant player in connection to the Indian Ocean and West Pacific, it has a downstream impact on weather here based on cycle of the MJO we're in. Phases 8 and 1 (which would be the weakest for the West Pac and Indian Ocean from a tropical standpoint) are favorable for the Atlantic for thunderstorm and tropical development in the summer...long story short is that we're about to see the MJO nudge into phase one, which would result in a potentially more active Atlantic basin.
There are three potential systems...one that pushed off of Africa yesterday, the second working across West Africa now, and the third in Central Africa. These three waves may become tropical systems over the next couple of weeks as they push west...and modeling does indicate the potential that one of these could work towards the US after Labor Day.
There will be a plethora of mines in the path ahead -- upper atmosphere down the line, dry air, and more. That said, the pattern is going to change from inactive to active in the coming days -- and it looks like a more active tropical season is forthcoming.