Is El Nino choking even as it seeks to peak?

Vinson Kurian Thiruvananthapuram | Updated on November 27, 2017 Published on July 01, 2014

Is the El Nino choking in its bid to extend its vice-like grip over the Equatorial Pacific? Yes, signs are there, says the latest update from the Australian Bureau of Meteorology.

Weak Nino now

While the tropical Pacific Ocean surface temperature is currently at levels typically associated with a weak El Nino, waters below the surface have cooled and atmospheric patterns continue to remain neutral.

However, over the past fortnight, changes have occurred in the atmosphere that may be a response to the warm surface waters.

This includes the dropping of the Southern Oscillation Index by over 10 points and reappearance of weakened trade winds.

The index is calculated using the pressure differences between the island of Tahiti in the South Pacific and Darwin in Australia.

The latest approximate 30-day Index value to 29 June is +0.1, a fall of over 10 points over the past two weeks.

Alert maintained

Sustained positive values of above +8 may indicate a La Nina event, while sustained negative values below −8 may indicate an El Nino event. Values of between about +8 and −8 generally indicate neutral conditions.

These changes would need to persist for several weeks in order for an El Nino to be considered established, and it remains possible they are simply related to shorter term weather variability.

Climate models surveyed by the Bureau continue to indicate that El Nino is likely to develop by spring 2014. The Bureau tracker remains at El Nino Alert, indicating at least a 70 per cent chance of El Nino developing in 2014.

The El Nino has cast a long shadow over the ongoing Indian monsoon which has delivered 42 per cent less rain in June.

Its performance for the crucial month of July will largely determine the prospects of the year 2014 kharif crop.

Published on July 01, 2014
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