India Met Department has assessed that the South-West monsoon may make an onset along the Kerala coast by Thursday.
In its earlier forecast, it had said that the onset might happen on June 7, which is today, with a model error of four days.
The Met said this morning that the monsoon has advanced into some parts of South Arabian Sea, the Maldives, the Comorin area as well as more parts of South-West Bay of Bengal.
"In view of strengthening of cross equatorial flows and deepening of westerlies over South Arabian Sea and development of a feeble offshore trough along Karnataka-Kerala coast, the onset of monsoon over Kerala is very likely by June 9 (Thursday)," the Met said.
Meanwhile, an upper air cyclonic circulation over East-Central Arabian Sea off Karnataka coast persists.
A counterpart circulation over West-central Bay of Bengal off North Andhra Pradesh and South Odisha coasts too persists.
These circulations are expected to play a key role in facilitating the onset and advance of rains over the Kerala coast and East Coast and North-Eastern States in the days to come.