
Note the twin tropical systems (both are official now) on either side of the equator. Not rare at all in the Indian Ocean and Western Pacific...
Indicative of a strong MJO pulse...interesting to see if it propagates East (and forms more twin cyclones, on one occasion there were TWO sets of twins in the Indian Ocean) and causes twins in the Western Pacific....leads to strong westerly wind surges along the equator.
Some papers seem to indicate that this occurs at times prior to an El Nino event (obviously, that's dependent on twin cyclones forming in the Western Pac, which could happen after it occurs in the Indian Ocean.)
The relationships are pretty complex, however.
http://www.iap.ac.cn/html/qikan/aas/aas ... 030604.pdf
http://www.soest.hawaii.edu/~bwang/bw/pubs/37.html
http://www.met.rdg.ac.uk/~ericg/publica ... l_JC03.pdf