Why are the tropics so active and when they could quiet down

Could see increase in activity through early October


ORLANDO, Fla.- – It seems like every day there is a new tropical wave to pinpoint in the Atlantic. Thankfully, steering currents have been kind to Florida to date. The short answer to why, is that we are in peak season. The long answer has to do with a grouping of clouds and rain that travels the globe.

Similar to El Nino or La Nina, the oscillation known as the Madden-Julian Oscillation, or MJO, can impact weather globally. When it comes to the tropics, the MJO can either enhance tropical activity or suppress it. In the case of the last week or so, and of the next couple of weeks, it may help to enhance tropical activity in the Atlantic.


The MJO moves eastward around the globe along the equator. The area of disturbed weather has moved out of the Western Pacific and into the Western Hemisphere, or our backyard. The MJO is partially responsible for the sharp increase in activity and it could be a player in more development through early October.

How does it impact the Tropical Atlantic?

When in the favorable phase, stormy weather in the Western Hemisphere, upward motion is increased and tropical activity can be enhanced. When in the unfavorable phase, the opposite is true and the Atlantic is quiet.

Tropical outlook over the next few weeks

The MJO looks to move into its enhanced phase for the Atlantic when it comes to tropical development. 

By the middle of October, the MJO will try to work its way back toward the Indian Ocean, putting most of the Atlantic in the suppressed phase, helping to limit development. The important thing to note is that the MJO is not the only player when it comes to the tropics. Even if the MJO is in the enhanced phase, other factors can work to suppress or vice versa. 


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