Cyclogenesis in an active MJO

As we go deeper into what looks like a very promising active MJO to study in the coming years. There appears to be some areas over the Indian Ocean that appear that are grabbing our attention for possible tropical storm formation. Lets look at the latest IR image from Meteosat 7 (taken from NRL)

Sattelite imagery showing latest activity over the Indian Ocean. Red circles depict areas of potential TC development, blue circle is the approximate region of the northern Rossby gyre and the red arrow roughly depicts the region is westerly wind bursts. The green square is showing the area of the active MJO.

The two red-orange circles denote the areas where significan tropical cyclone development is expected. Both features show deepening low pressures, increasing vorticity (rotation) and curving bands. The first features, denoted as Invest 98B, has the highest probability of development as of the latest Joint Typhoon Warning Center (JTWC) advisory. This area has also been looked at by the P3 aircraft obtaining data for DYNAMO.

The second area (pictured below), recently denominated as Invest 96S has a medium chance of development as of this writing.

Contours of height and vorticity with overlaid winds and nondivergent winds are depicting the Invests very well. The significance of this event is that these cyclones are forming while an active MJO is in place. Now this is in no way rare, active MJO phases are notorious for providing favorable environments for TC formation. The reason is because of the convective activity and deep moisture provided by it. Additionally, the Rossby gyres, which are usually at the western edge of the active phase, provide some cyclonic rotation,  favorable for development.

To add to this, convergence in the lower- mid levels is impressively high near both invest areas. Both systems are also fairly close to the equator, being at about 6 degrees of latitude. Also notice the significant divergence near the northern disturbance.

Irrotational winds and moisture convergence from the latest GFS run (12ET) 

 Overal we continue to observe an equatorial region dominated by the active MJO, and satellite imagery depicts it very well, with a somewhat skewed swallowtail feature very apparent in IR imagery.  It will be very interesting, and exciting to see how these systems continue to develop, as well as the MJO itself.