Arabian Sea to soon host twin low-pressure areas

Twin low-pressure areas are forecast to develop over the Arabian Sea — far off the Yemen coast and nearer home, off Kerala — two days apart on May 29 and 31, as the build-up for the onset of monsoon over mainland Kerala begins in right earnest. The onset is forecast to be delayed by four days until June 5.

Monsoon enters deeper into Bay

In fact, the India Meteorological Department (IMD) on Wednesday issued a depression formation alert over the South-West Arabian Sea (off Yemen). The twin systems share the same monsoon flows — one racing away early to acquire storm strength keeps the other under check till the former weakens and dies out.

Meanwhile, enhanced cloud cover and deepening of south-westerly winds to the required heights meant that the Bay arm of the monsoon advanced into more parts of South Bay of Bengal, most parts of the Andaman Sea, and the Andaman and Nicobar Islands on Wednesday. The monsoon had entered the South-East Bay on May 18, helped in by the marauding flows associated with super cyclone Amphan.

Plots entry into Arabian Sea

The IMD said conditions are becoming favourable for the Arabian Sea arm of the monsoon to advance into parts of the Maldives-Comorin and adjoining South-East Arabian Sea, remaining parts of the Andaman Sea, and more parts of South and Central Bay during the next two days. Fishermen are advised to avoid deep-sea fishing from May 31 to June 4.

The rainfall trend along the South Peninsula and along the West Coast is: May 28: Heavy rainfall at isolated places over south interior Karnataka, Tamil Nadu, Puducherry, Kerala, and the Andaman and Nicobar Islands; May 29: Heavy rainfall at isolated places over south interior Karnataka, Tamil Nadu, Puducherry, Kerala, and the Andaman and Nicobar Islands.

Floods over NE India

The low-pressure area off Kerala is forecast to travel north close to and grazing the West coast. The likely rainfall trend is: May 30: Heavy rainfall very likely at isolated places over coastal and south interior Karnataka, Kerala and Lakshadweep; May 31: Heavy rainfall likely at isolated places over coastal Andhra Pradesh, coastal Karnataka, Kerala, Lakshadweep, Konkan and Goa.

Towards East and North-East India, the flood situation looks grim with strong southerly winds pumping oodles of moisture from the Bay of Bengal. The IMD has forecast heavy to very heavy rainfall with extremely heavy falls at isolated places over Meghalaya, Tripura and Mizoram during the next two days.