N-E Bay of Bengal braces for depression

The Bay of Bengal is bracing for the next monsoon depression as an existing low-pressure area over East-central Bay became well-marked on Wednesday.

MORE RAINS SEEN

The European Centre for Medium-Range Weather Forecasts and other international models are of the view that an incoming western disturbance might ‘gulp' the system in and dump it over Myanmar/Bangladesh. This would likely set off another round of showers over Central India and the West Coast, holding up the withdrawal of southwest monsoon for longer.

An India Meteorological Department (IMD) update on Wednesday and valid until Saturday said that fairly widespread rain or thundershowers would occur over Madhya Maharashtra, Konkan, Goa, Coastal Karnataka, Kerala and Andaman and Nicobar Islands.

Leading international weather models are of the view that conditions for the onset of northeast monsoon may set in over Tamil Nadu coast towards the end of next week (October 25 to 30).

A signature burst in accumulated rainfall amounts has been indicated for Southern and adjoining Interior Tamil Nadu and Kerala during the week.

In fact, the IMD expected fairly widespread rainfall over Peninsular India from Monday onwards. The rains would get a boost as a strong wet phase of the periodical Madden-Julian Oscillation (MJO) wave settles over Equatorial Indian Ocean and Extreme South Peninsular India.

This would replace as an equally strong dry MJO phase transits the region towards the east.

The MJO wave travels in the higher levels of the atmosphere periodically and in alternating dry and wet phases with profound influence on weather over ground.

The wet phase of the MJO has been known to set up monsoon onsets, low-pressure areas, depressions and even cyclones.

Models are also indicating that the string of cyclonic disturbances along the Mumbai latitude and the resultant non-seasonal rains would also have migrated to more southerly peninsular latitudes to set the stage for northeast monsoon.

IMD forecasts point to a cyclonic circulation settling in over Southeast Tamil Nadu and adjoining Southwest Bay of Bengal by Monday.

This would be followed by establishment of monsoon easterlies over the next couple of days, which may strengthen in due course and set the stage for the monsoon on retreat or northeast monsoon.

WIDESPREAD RAIN

Meanwhile, fairly widespread rainfall has been reported over South Peninsular India and along the West Coast during the 24 hours ending Wednesday morning.

The rains were scattered over Central India, East Uttar Pradesh and Bihar during this period, an IMD update said.

A satellite cloud imagery showed the presence of convective (rain-causing) clouds over parts of East-central Arabian Sea, East-central and adjoining West-central and Northeast Bay of Bengal and North Tamil Nadu.

Scattered rain or thundershowers are is expected to occur over the Western Himalayan region during Thursday as the western disturbance drifts in. It is expected to increase in intensity thereafter.

Scattered rain or thundershowers are also expected to occur over Madhya Pradesh, Chhattisgarh, Marathwada, Vidarbha and the Northeastern States.

Scattered rain or thundershowers have been forecast for East Uttar Pradesh and Bihar during next two days and decrease thereafter, the IMD outlook said.