Conditions are becoming favourable for the onset of South-West monsoon over Kerala over the next three to four days, the Met Department said on Wednesday.

GAME-CHANGER

South Arabian Sea, Maldives and the Comorin region, the last three pit-stops on the home stretch, would be covered in that order over the next two days. The ‘low’-turned-depression in the North Bay of Bengal is proving the game-changer, according to seasoned monsoon watchers.

The rains are expected to gather strength after onset, since a Madden-Julian Oscillation (MJO) wave is set to arrive into South Arabian Sea.

The MJO wave travels from west to east high up in the atmosphere, but has significance influence on ground weather. Suitably timed pass-over has also underwritten onset of South-West monsoon in the past.

The pass-over this year follow the onset just by a day or two, say forecasts.

RAIN WAVE

Meanwhile, a US storm tracker agency said that the MJO activity from around June 5 might also set off a rain wave to break away and head towards Oman coast.

It would leave behind a smaller mass of rain, which is shown as slithering up the Konkan coast and land up over south-west Gujarat.

Tuesday’s low-pressure area intensified into a depression and was looking to force its way into Bangladesh coast on Wednesday, second such to do so after cyclone ‘Mahasen.’

Regional Specialised Meteorological Centre, New Delhi, expected the depression to cross the coast in the evening.

But US Joint Typhoon Warning Centre suspected that the storm could stay put over Head Bay of Bengal (off Kolkata) for the night and wriggle into Bangladesh coast the next morning.

If this were to prove true, high winds and pouring rain could bear down on Kolkata, parts of East India and North-East India, Bangladesh and Myanmar.

vinson.kurian@thehindu.co.in