New Delhi, 2 June

The southwest monsoon is expected to onset over Kerala around June 4, the India Meteorological Department (IMD) said on Tuesday.

Typically, the monsoon arrives in Kerala around 1 June, marking the beginning of the southwest monsoon season (June-September).

"Conditions are favourable for further advance of southwest monsoon into some more parts of southwest and southeast Arabian Sea, Lakshadweep Islands, some parts of Kerala and Tamil Nadu around June 4," the IMD said in its daily forecast.

It added that the monsoon will also advance in some more parts of the southwest, westcentral, eastcentral and northeast Bay of Bengal, and the remaining parts of the southeast Bay of Bengal around this date.

The IMD had earlier said the monsoon onset over Kerala would take place on 26 May. However, it was delayed, and the department stated on 29 May that the onset could occur the following week.

Last week, the department in its revised forecast for the rainfall during the season said it would be below normal.

The IMD stated that India is expected to see 90 per cent of the long-period average (LPA) this year.

LPA refers to the rainfall recorded over a particular region for a given interval, such as a month or a season, averaged over a long period of time, typically 30 to 50 years.

The LPA of seasonal rainfall over the country as a whole, based on data from 1971 to 2020, is 87 cm.

If the monsoon season sees less than 90 per cent of LPA rainfall, the IMD classifies it as "deficient".

One reason for the below-normal rainfall could be the emergence of El-Nino conditions, which lead to less rain during monsoon in the country.

Currently, neutral El Nino-Southern Oscillation conditions are transitioning towards El-Nino conditions over the equatorial Pacific region.

The IMD said El-Nino conditions are likely to be weak in June, and moderate to strong in September.