The Hindu Business Line : Weather models split over La Nina

Leading weather models are split over the possibility of a La Nina materialising over the Equatorial East Pacific during that time of the year when predictability is at its lowest.

A La Nina year has largely coincided with a successful Indian monsoon, with a warming anomaly and associated cloudiness becoming typically prominent over the nearest Western Pacific. This is matched by a corresponding cooling of the seawaters off the Peru coast in the extreme East Pacific.

Contrasting outlooks

An update put out by the Australian Bureau of Meteorology (BoM) on Wednesday said that the cooling phase, which had approached La Nina-like conditions, might be showing signs of decay of late.

But the equally respected European Centre for Medium-Range Weather Forecasting (ECMWF) maintains in its three-month (May-June-July) outlook that "weak La Nina conditions" are set to prevail.

However, loudiness remains strongly suppressed around the International Date Line, which, again, is supportive of a La Nina.

Speaking to Business Line, Dr Akhilesh Gupta of the National Centre for Medium Range Weather Forecasting (NCMRWF) said that it was too early to have a final word on the issue. It would be better to waituntil the middle of May.

He also said that latest sea surface temperatures (as on Wednesday) were indicative of a weak La Nina, with the Eastern Pacific cooler by 2-3 degrees C while the Western Pacific had warmed up by an equal margin.

A `typical La Nina' would record anomalies of the order of four deg C and above on either side of the Pacific, Dr Gupta said.

April heating

Heating of Central India in the month of April is crucial from the monsoon viewpoint, Dr Gupta said. Right now, the temperatures are coming down under the combined effect of western disturbances in the North-West and an easterly wave approaching the peninsular coast.

But model predictions indicate that both these systems may start to weaken after April 18, yielding place for warmer climes to set in. Mercury is seen peaking over these areas gradually to the desired levels, preparing the ground for the monsoon.

More Stories on : Climate & Weather | Climate & Weather

Article E-Mail :: Comment :: Syndication :: Printer Friendly Page