The Southwest Monsoon arrived over Kerala on Thursday, three days after its normal onset date and five days after IMD’s forecast date, and it is likely to cover most parts of India by the third week of June, although concerns remain about the volume of rainfall.IMD has said there is a 60% probability of a deficient monsoon, rainfall that is less than 90% of LPA. (PTI)Monsoon normally arrives over Kerala around June 1. IMD had forecast on May 15 that this year, the southwest monsoon is likely to set in over Kerala on May 26 with a model error of ± 4 days. IMD has also predicted that monsoon rainfall this year will be 90% of the long period average, which translates into abelow-normal monsoon. Still worse, IMD has said there is a 60% probability of a deficient monsoon, rainfall that is less than 90% of LPA.But its onset over Kerala, a milestone in its progress, will bring some cheer in a country where 51% of farmed area, accounting for 40% of production, is rain-fed.“During the past 2 days, convective cloudiness has increased over the Southeast Arabian Sea. The depth of westerlies over Southeast Arabian Sea extends up to 4.5 km above mean sea level. The strength of Westerlies in the lower levels is about 20-25 knots. There has been widespread rainfall with isolated heavy rainfall over Kerala during the past 2 days. Considering all the above satisfied conditions, Southwest Monsoon has set in over Kerala on June 4,” IMD saidin a release.Also Read | Indians can now bet on the monsoonOn Thursday, the monsoon advanced into remaining parts of southwest and southeast Arabian Sea, some parts of westcentral and eastcentral Arabian Sea, entire Lakshadweep islands, Kerala, Mahe, some parts of Karnataka, Tamil Nadu, remaining parts of Comorin area, southeast Bay of Bengal and some more parts of southwest, westcentral, eastcentral and northeast Bay of Bengal on Thursday, according to the weather office.The northern limit of monsoon passes through Mangalore, Uthagamandalam, Kodaikanal and Thoothukudi.Conditions are favourable for further advance of southwest monsoon into some more parts of central Arabian Sea, all of Goa, some parts of Maharashtra and Andhra Pradesh, some more parts of Karnataka, remaining parts of Tamil Nadu, Southwest Bay of Bengal, some more parts of Westcentral, Eastcentral and Northeast Bay of Bengal, and some parts of Northeastern states during the next two to three days, IMD added.“We are expecting a good surge during the next one week. We can expect monsoon to reach parts of Karnataka, Tamil Nadu, southern parts of Andhra Pradesh, Goa, Konkan, parts of Maharashtra, northeastern states. So it is looking good for the next few days,” said M Mohapatra, director general, IMD.“Over Kerala, rainfall will reduce this week.Otherwise, the monsoon is likely to reach many parts including parts of Northwest India by June 15-16,” said Mahesh Palawat, vice president, climate and meteorology.El Niño conditions are developing and are set to influence global temperature and rainfall patterns, increasing the risk of extreme weather over the coming months, the World Meteorological Organization (WMO) warned on June 2.A new WMO El Niño/La Niña Update indicates an 80% likelihood of an El Niño event during June-August 2026. Probabilities for El Nino conditions to continue until at least November are near or above 90%. Most forecast models suggest it will be at least moderate – and possibly strong, WMO flagged.Rainfall is likely to be below normal during the June-September 2026 southwest monsoon season across much of South Asia, with the strongest signal over central regions, according to a seasonal forecast by WMO issued on April 30. The map issued by WMO showed below normal rain over almost all of India.