While most of us thaw out after a rough February into the first week of March, winter weather-wise, the Southern Hemisphere is boiling with deep convection that has spawned three tropical cyclones near Australia and the South Pacific, one tropical cyclone in the West Pacific (a twin of sorts to TC Pam in the South Pacific), and an invest area near the coast of southern Brazil.  There is a weak El Nino that is centered near the dateline in the West Pacific and there is currently a strong westerly wind burst associated with the current state (Phase 6 moving to 7) of the Madden-Julian Oscillation (MJO).  TC Pam and TS Bavi look to have formed near this burst as part of the overall monsoon trough that straddled the equator.  TC Nathan may have also formed due to the strength of the monsoon trough, while TC Olwyn formed well to the west on the other side of Australia.

I have put together some animations and a snapshot of the of the four storms near Australia and Guam.

MTSAT-2 Infrared satellite image of four concurrent tropical cyclones in the western Pacific and eastern Indian Oceans valid at 2032 UTC on 03/11/2015.

A four day animation that shows the development of TC Pam, TC Nathan, TC Olwyn, and TS Bavi valid from 03/08/15 to 03/11/15.

MTSAT-2 Infrared Satellite imagery with GLD-360 lightning strikes overlaid showing the lightning distribution (cloud-to-ground and some intra-cloud) associated with all four tropical cyclones valid from 1432 UTC on 03/10/2015 to 2032 UTC on 03/11/2015.

Finally, a new invest area has been identified near the southern coast of Brazil on the tail end of a mid-latitude storm system.  This is rare, but not unprecedented as this area occasionally sees subtropical development during the Southern Hemisphere summer.  The RGB Air Mass animation below shows the system still developing, but appears to be embedded in a cold core system as indicated by the orange, red, and purplish coloring.  There is a significant amount of upper-level dry air that the system has to fight through, but water temperatures are slightly above normal (+0.5C), so some additional development is possible (thank you to Dr. Jeff Masters for the information).

SEVIRI RGB Air Mass animation of Invest 90Q in the South Atlantic valid on 03/11/2015.

Thanks for reading!  I’ll try to follow up on these systems as they develop.