South west monsoon may hit Kerala coast around June 4: IMD

New Delhi: The India Meteorological Department (IMD) on Tuesday said that the South West Monsoon may hit the Kerala coast around June 4 – nearly nine days after the initial onset day announced by the agency. The possible reason behind the delay, according to the experts, is the El Nino.

“Southwest monsoon is likely to set in over Kerala around June 4. Isolated heavy to very heavy rainfall (7-20 cm) is very likely to occur over Kerala and isolated heavy rainfall over Tamil Nadu and Karnataka in next 6-7 days,” the IMD said in a statement.

The met agency last month announced that the monsoon may reach Kerala by May 26, five days ahead of its scheduled date of June 1. This didn’t happen.

“Monsoon flow needs a 4.5 km depth in westerly winds, which has been lacking . The situation has started improving today because of which we made the June 4 forecast,” Mrutyunjay Mohapatra, director general of meteorology told DH.

Equatorial westerly winds act as the structural engine of the south west monsoon, providing both the wind flow that enters the Indian subcontinent and the necessary atmospheric conditions to trigger it.

Weather scientists say the delayed arrival is due to the El Nino that even in its formative period can influence the monsoon.

“Late onset and delayed progress of monsoon can happen in an El Nino year. The relationship between El Nino and south west monsoon is not a master-slave relation. Rather it is an interactive process and can influence the monsoon even at the beginning,” veteran scientist M Rajeevan, former Secretary, Union Ministry of Earth Sciences told DH.

The World Meteorological Organisation on Tuesday said that fueled by unusually warm ocean waters in the tropical Pacific, El Nino conditions are developing and are set to influence global temperature and rainfall patterns, increasing the risk of extreme weather over the coming months.

A new WMO update indicates an 80 per cent likelihood of an El Nino event in June to August period and the chances for such an El Nino to continue until at least November are near or above 90 per cent.

Although some uncertainty remains about El Niño peak strength and timing, most forecast models suggest it will be at least moderate – and possibly strong.

Delayed arrival of the monsoon has added to people’s apprehension over a “below normal” south west monsoon with IMD further downgrading its April forecast to claim that the country would be looking at its worst monsoon scenario in a decade with 90 per cent of average rainfall expected between June and September. El Nino was the key factor behind the downgrade.

The MeT agency has also predicted that moderate to severe thunderstorm activity with squally wind speed up to 40-50 km per hour is likely over many parts of northwest, central & east India and south peninsular in this week.