Monsoon advances with little help from Laila

Aided by cyclone Laila, southwest monsoon today moved a little further in the Bay of Bengal covering all the islands in the Andaman archipelago.

The weatherman said that formation of a cyclonic storm over southwest Bay of Bengal and strengthening of westerly winds in the region were favourable conditions for the forward march of monsoon, that powers the country's trillion-dollar economy.

However, scientists were keenly tracking the movement of cyclone Laila as a similar weather system -- cyclone Aila -- had disrupted the monsoon build up last year.

"Will Laila be another Aila?" is the question bothering weather scientists.

A section of meteorologists believe that cyclone Laila may not affect the onset of monsoon over Kerala as predictions suggest that the inter-tropical convergence zone (ITCZ), considered as the birth place of low pressure systems, in the Arabian Sea as also the Bay of Bengal may remain active even after the weakening of the cyclone.

An active ITCZ raises the hope for possible formation of an onset vortex like low pressure system over the Arabian Sea subsequent to the weakening of cyclone.

Scientists believe that the monsoon flow over the Arabian Sea is still in the process of building and hence if the cyclone crosses the eastern coast May 21, there is still enough time available for monsoon to evolve and cause onset over Kerala by May 30 as predicted by IMD.

"Model predictions suggest that even after weakening of the present cyclone, the strength of the south-westerly flow of the monsoon over the Bay of Bengal remains intact which would help building of flow over the Arabian Sea subsequently," they said.

The India Meteorological Department (IMD) had yesterday announced the onset of monsoon over Andaman and Nicobar Islands, a development that set the stage for the four-month annual rainfall season after a year of severe drought.

The IMD last month forecast a normal rainfall for this year with a precipitation of 98 per cent of the Long Period Average (LPA), subject to a model error of plus or minus 5 per cent for the entire season (from June to September).

Last year, the weather office had forecast a rainfall of 96 per cent plus or minus 5 per cent in April and then fine tuned it to 93 per cent plus or minus 4 per cent. But, the country received a rainfall of 77 per cent of the LPA only for the season.

The normal monsoon forecast is expected to bring cheers to over 235 million farmers who had faced drought last year due to failed monsoon.

A good monsoon could help in sowing of rice, sugarcane, soyabean and corn and lead to a rebound in the agricultural output.