Bay storm stalls, but vindicates peril in seas from Lanka to S-E Asia

The India Met Department seems to have withdrawn the watch for a depression as a well-marked low-pressure area drifted around over the Bay of Bengal for the third day on Tuesday.

But at least on global models signals, it is too early to make the call since the system could flare up one last time off the Odisha coast in a couple of days.

Meanwhile, the Australian Bureau of Meteorology on Tuesday explained why the seas linking the Philippines westward to Indonesia, Malaysia and Sri Lanka have become treacherous now.

Disappearance in stormy weather and the crash into the Java Sea of AirAsia Flight QZ8501 has brought to light the hazard associated with flying in these conditions.

The seas around here form part of the "inter-tropical convergence zone" known for disturbed weather almost the year-round.

The Indonesian Met authorities have said that huge storm clouds rising up to more than 50,000 feet were present at the time when the ill-fated AirAsia liner sought a change in flight path before going out of radar.

The convergence zone shifts north and south seasonally with the sun. Post the South-West monsoon in India, the zone is shifting to the south and preparing to trigger the Australian monsoon.

What apparently makes the stretch even more treacherous is the adverse weather regime controlled by an active phase of the Madden-Julian Oscillation (MJO).

The wave travels high in the atmosphere but sets up huge thunderclouds and storms at the ground level.

It is also known to precipitate the monsoons over the area under its footprint.

Australia is waiting for the east-moving wave, anchored for days now over Sri Lanka, the Bay of Bengal and South-East Asia, including much of Indonesia, to move further east and set up the monsoon there. Its disruptive power is already chronicled in the manner in which it has fathered two tropical storms – tropical storm Jangmi in the northwest Pacific and tropical cyclone Kate in the tropical Indian Ocean.

A western disturbance has developed on the Indo-Pakistan border and is likely to bring warmth in the cold climes prevailing in northwest India.