The storm-enabling Madden-Julian Oscillation (MJO) wave in the higher levels of the atmosphere has rode out of the equatorial Indian Ocean and the adjoining Arabian Sea and Bay of Bengal.
But that would not prevent the Bay from getting into active mode from the weekend, as per projections by India Met Department as well as international models.
From here, its west-northwest track would likely take it to the South-East coast of Tamil Nadu where it would break up into thunderstorms (mostly over the Central region and the South).
India Met projects the system as waiting in the sea off the North-East Sri Lankan and South-East Tamil Nadu coasts by November 18.
Pilot rains are expected to lash the Tamil Nadu coast from at least three days ahead as stronger easterly winds buffeting the system blow in.
Record storms The Australian Weather Bureau said the MJO wave has left equatorial Indian Ocean to reach within the longitudes of the island continent.
The wave was particularly active over the Arabian Sea helping generate two of the strongest cyclones in quick succession, a spectacle not witnessed any time during the past.
Just one week after tropical cyclone ‘Chapala,’ the second-most intense tropical cyclone on record for the Arabian Sea, another major tropical cyclone ‘Megh’ had impacted the region.
Since 1990, when reliable records commenced, only five tropical cyclones of this intensity have been recorded in the Arabian Sea, and no previous season has seen more than one.
El Niño update The El Nino has been in place for about six months and has been a strong one, comparable to the events of 1997-98 and 1982-83, the Bureau said.
International models suggest the peak in El Nino sea surface temperature is likely to occur within the next month or two. The event is expected to persist into the first quarter of 2016.
The positive Indian Ocean Dipole (IOD) event also persists. It has been in place for over three months. International climate models expect the positive IOD to break down during November and early December.
The El Nino has been generally helpful for the North-East monsoon though the exact impact of the IOD, which mimics El Nino in the Indian Ocean, would become known only later.
Earlier, India Met Department had forecast a normal to above normal North-East monsoon during this year.