With the India Meteorological Department (IMD) announcing May 30 as the likely date of onset of the South-West monsoon over the Kerala coast, the focus shifts to the behaviour of the seas on either side of the Indian peninsula.
In the past, the onset phase has witnessed formation of low-pressure areas, depressions and even cyclones. The strengthening monsoon flows across the Equator warrant a constant watch in this context.
Early forecasts signalled that the Bay of Bengal just to the east of Chennai would demand attention for the likely formation of one such system, whose track is yet to be ascertained.
One of the global models suspected that the Central Arabian Sea, too, might throw open such a possibility, with a low-pressure area posited for a movement towards the Arabian Gulf.
On Tuesday, satellite pictures showed a heavy build-up of clouds along and off the Maldives atolls, and to the south-west of the Lakshadweep Islands with Minicoy in the line of sight.
The situation is almost similar in the Bay of Bengal and the area southward of Sri Lanka, extending all the way into Myanmar and Thailand, which lie to the east and north-east of the Andaman & Nicobar Islands.
The monsoon had advanced into these islands, its first port of call in the territorial waters, on May 14, a week earlier than the mean date of May 20, with standard deviation.
On Tuesday, the Thailand Met Department issued an alert to all ships passing through the Andaman Sea to exercise caution due to high winds and large swells rising up to four metres in height.
It also located an active low-pressure area covering the Gulf of Martaban in Myanmar, which is expected to move in-shore during the next two days, bringing with it heavy to very heavy rain along the coast and the interior.
The monsoon has covered the Andaman Sea, the Gulf of Thailand and South Thailand, assuring continuous rain cover over the country, the update said.
Meanwhile, over land in India’s South, the pre-monsoon regime held sway with clouds hovering over an area extending from Thrissur and Kochi to Alappuzha in Kerala and from Pollachi, Valparai, Dindigul, Madurai, Rajapalayam, Karaikudi and Thoothukudi in Tamil Nadu.