Weathermen at Skymet are of the view that prior to the onset, such weather systems either in the Bay of Bengal or in the Arabian Sea help the cross equatorial flow to strengthen, after which the strong southwesterly winds sweep across Kerala coast, announcing the arrival of Monsoon.
The map in the article shows that after on time arrival, the eastern arm has made more progress than the western arm and has reached Myanmar early this year. The green line shows the actual Monsoon line which indicates that the eastern arm of Monsoon line has already entered Myanmar and is close to northeastern states, while the western arm has covered some parts of Southwest Bay of Bengal. The red-dotted Monsoon line in the map has been drawn by Skymet Meteorology Division in India.