Monday, June 9, 2014

All monsoon forecasts go for full toss: "Super" El Nino dissipates completely. Indian Ocean Dipole turns negative.

The latest model from the Bureau of Meteorology (BoM), Australia confirms what was billed as the "Super El Nino" just dissipated - second time in recorded history, the first being in 2012.  The Sea Surface Temperatures in the Nino monitoring region are neutral while the atmosphere - Southern Oscillation Index (SoI) is La Nina like. Both together should normally had been good news for the India monsoon but for the fact the India Ocean Dipole (IOD) turning negative. This article explains why a negative IOD can derail the Indian Monsoon. Later today, it is interesting what the IMD's revised forecast has to say...

(Vinson Kurian, HinduNBusinessLine) In what looks like blow to prospects for the monsoon, an unfriendly weather pattern seems to be emerging in the Indian Ocean.

Reference here is to the negative Indian Ocean Dipole, signs of development of which have been indicated by the Australian Bureau of Meteorology.

Indian Ocean Dipole (IOD) mimics the larger El Nino-La Nina of the Pacific in India's own backyard waters. When the IOD is negative, east Indian Ocean (below Bay of Bengal) warms up anomalously.

The warmer waters here will lead to usurping locally of moisture that is headed towards the west Indian Ocean. This in turn leads to the 'disarming' of the monsoon flows in the west where they turn southwesterly and get directed towards south Arabian Sea and the Kerala coast.

The IOD index may already have started dipping to the 'negative' as per the June 1-update of the Australian bureau.

When acting in concert with a building El Nino in the Pacific, the net impact on monsoon could be larger than expected, say monsoon watchers.

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