city anchor: Delayed by 4 days,monsoon likely to hit city by June 12

Meanwhile,the onset of monsoon over Kerala,which was forecast for June 1,is likely to be pushed ahead to around June 4-5 — well within the time frame predicted by the IMD in the long range forecast.

Met officials said the south-west monsoon has advanced over Maladives and south-west Bay of Bengal and some more parts of the Arabian sea. “There is a lull in its progress. We are hopeful that the conditions will be favourable in the next 48 hours. Its onset over Kerala,which was declared as June 1 with a model error of plus or minus four days,should be seen well within that period,maybe towards the latter part of the first week of June,” said Devi.

The monsoon was stuck at the Maldives-Colombo alignment. It is expected to advance into parts of southeast Arabian Sea (off Kerala),Maldives,the Comorin areas and the rest of the Andaman after the next 48 hours. With the progress of monsoon,the Met department has also forecast rainfall all along the west coast due to the moisture in the air.

The south-west monsoon advanced over Andamans by May 23,which usually sets the onset date over Kerala. However,with conditions in the Arabian Sea not conducive,the monsoon current is yet to reach the mainland. Last year,the monsoon advanced over the Andamans on May 29 and simultaneously advanced over Kerala on the same date.

June 1 is the normal date for the onset of the system over Kerala,which is the entry point for monsoon into the Indian mainland. Historical data show that the monsoon keeps its date with a standard deviation of just one week. There have,however,been instances when the onset occured around mid-May,or was delayed till mid-June. According to IMD statistics,the earliest recorded onset was in 1918,when it set in on May 11,and the most delayed onset was in 1972 when south-west monsoon arrived on June 19.

Earlier,the IMD had issued a forecast of a normal monsoon this year,with a rainfall of 99 per cent of the long period average.