With Cyclone Mocha making landfall on Sunday and is expected to weaken into a depression by Monday, all eyes are now on the southwest monsoon. The southwest monsoon is expected to reach the Andaman sea by May 20 and cover the entire Andaman and Nicobar Islands on May 22. It is likely to reach Kerala by June 1 with an error margin of +/-5 days.
The countdown for the arrival of the monsoon has already begun with the formation of the high pressure area called ‘Mascarenas High’ near Madagascar, from where the monsoon originates.
The formation of Cyclone Mocha over the Bay of Bengal ahead of the monsoon has raised some concerns as cyclones ahead of the monsoon usually delay its onset. However, Mocha will not have much influence on the onset as it was formed well before the set-in of monsoon winds. But if another cyclonic system formed around the time of the arrival of the monsoon near Andaman, it would have a direct influence on the monsoon onset, said a senior scientist at the India Meteorological Department (IMD).
Though the threat of ‘El Nino’, a cyclical phenomenon of warming in the central Pacific which is linked to reduced rainfall activity, looms large, Kerala is likely to get its due share of rainfall this year. The El Nino effect is expected to cause reduced rainfall in August and September, when the northern parts of the country receive rainfall, while Kerala gets majority of the rain in June and July. There was a slight aberration in the past couple of years which saw the State receiving the highest rainfall in August.
“However, considering below normal pre-monsoon showers in April and May this year, the southwest monsoon is likely to be on a vigorous mode in Kerala in June and July,” said the scientist. There might be some chances of reduced rainfall in August and September, but this would be offset if there was a positive Indian Ocean Dipole — warmer sea surface temperature over the Arabin sea. There would be clarity on these developments in the coming months. At present, Kerala was poised to get normal rainfall, said IMD sources.
The IMD will soon review the situation and come up with a more accurate forecast, including the arrival of the monsoon in Kerala, spatial distribution, and its progress towards the North.
