India Met Department (IMD) has issued an alert about the probability of a monsoon depression forming in the Bay of Bengal in what is a calibrated run-up leading to onset of the seasonal rains over Kerala.
The low-pressure area over East-Central and adjoining West-Central and South-East Bay of Bengal (around the Andaman & Nicobar) Islands has already intensified a round to become 'well-marked.'
This is expected to become a depression over the next 24 hours, the Met said in its afternoon bulletin.
This is expected to expand coverage of the monsoon over the Bay as well as in the Arabian Sea to the other side of the peninsula, before precipitating the onset over Kerala by Tuesday/Wednesday next.
Simultaneously, the monsoon will make an onset over the North-Eastern States thanks to its Bay arm; the Arabian Sea arm is what brings the rains into Kerala.
Meanwhile, the European Centre for Medium-Range Weather Forecasts sees the prospective depression in the Bay intensifying into a tropical cyclone.
The US Joint Typhoon Warning Centre (JTWC) observed that the building storm enjoys the support from the sea and the atmosphere to do exactly this over the next couple of days.
Eyeing Bangladesh?
The European Centre suspects that the system would grow into considerable strength ahead of its landfall over the Sunderbans, adjoining North Bangladesh and India's North-Eastern States.
The JTWC located the system 963 km south-southwest of Chittagong in Bangladesh early this morning.
The ferocity of the monsoon onset in Sri Lanka triggering floods and landslides and claiming 90 lives as of yesterday should make authorities on India's West Coast sit up and take notice .
The monsoon has covered only the southern parts of the island nation, as is clear from the depiction of its northern limit by the IMD.
It expects the monsoon to deliver above normal rain over parts of the extreme South Peninsula and the North-East during the first two weeks after onset.
The US Climate Prediction Centre points to the Western Ghat areas along Goa and Konkan, Coastal Karnataka and North Kerala as areas likely to receive heavy rain during June 2 to 8.
Arabian sea act
After the would-be cyclone in the Bay dissipates, the monsoon activity is expected to shift to the Arabian Sea with the maximum of the heavy rainfall spending out in the seas.
The West Coast would only get a minor share initially, especially along the aforementioned Ghat areas, which are in any case prone to flooding and landslides.
The US National Centres for Environmental Prediction is of the view that the Konkan-Goa-Coastal Karnataka-North Kerala belt would witness heavy rainfall during June 4 to 12.
Meanwhile, some models projected the possibility of the strong monsoon flows throwing up a 'low'/depression in the Arabian Sea off Goa-Konkan, which could scale up rainfall manifold.
This system could however steer away from the West Coast and a track along until just short of the Gujarat coast, before moving further out into the sea.
By this time though, the monsoon would have covered the entire South Peninsula, these models suggest.