After the brief life-span of TS Chantal, the tropics are now quiet again. Part of the reason behind this is climatology: the tropics are generally very quiet during this period of July. The other reason is the MJO or Madden-Julian Oscillation. Think of the MJO as a period of fertility in the tropics. When the MJO is present, upward motion or tropical convection usually blooms and often leads to tropical cyclone formation during summer months. On the flip side, when the dry phase of the MJO rolls around, the air is converging and sinking, not allowing much tropical convection to occur. While it’s possible to have tropical cyclones form during the dry phase of the MJO, experience shows that a favorable MJO pulse often leads to the development of tropical storms and hurricanes. Right now, the MJO for the Atlantic Basin is taking some time off.
In fact, the MJO is not really amplified anywhere across the globe at the moment and as such, the tropics world-wide are generally quiet. There is one area of growing convection in the west Pacific that has a chance of developing in the coming days but that’s it. Without an amplified MJO pulse, it looks like the next several days at least will be nice and quiet. I see nothing of concern within the global models over the next week to 10 days. Once we get in to August, climatology begins to shift and it is possible that another favorable MJO pulse will coincide with that shift and things should be quite busy later in the month. For now, enjoy the calm conditions while they last.