This year, the Indian Meteorological Department (IMD) had predicted that it will hit the southern State on May 30.According to Skymet, a private forecasting agency, monsoon arrived over Andaman and Nicobar Islands on May 16, three days prior to the onset date. Since then, the advance has been slow. By May 21, the southwest monsoon advanced over Bay of Bengal touching southern parts of Sri Lanka. But here on, the monsoon stagnated for a week.The Arabian Sea branch of the southwest monsoon made very slow advance and is yet to reach the extreme southern tip (Kerala) of India. Cloud build up on either side of the sea was looking promising till a few days back for the timely onset over Kerala. However, it slowed down as the cloud pattern became a little diffused and unorganised, Skymet said.However, the IMD has refused to call it a delay, but said that the progress was sluggish. As per our forecast, there is +/ difference of four days, which is from May 27 to June 3.At this moment, monsoon has already entered the Arabian Sea, crossed Sri Lanka and entered the Bay of Bengal. We are closely monitoring its progress. During the progress of monsoon, it is often observed that its pace varies, said Krishnanand Hosalikar, Deputy Director, IMD.