Met sets up watch for low-pressure area in Bay in next four days

India Met Department (IMD) has formally notified the possibility of a low-pressure area forming over West-Central and adjoining North-West Bay of Bengal in the next four to five days.

A US National Weather Services forecast had last week alluded to this event, precipitated in continuum with destructive super typhoon Mangkhut in the West Pacific and a preceding system.

Trough to shift

As if on cue, the eastern end of the monsoon trough across the plains of North India that lies currently nestling along the Himalayan foothills, would slide South and dip into the Bay.

The trough opens itself up to any system developing in the Bay to receive the monsoon easterlies and the rains heralded by them into the hinterlands of East and Central India.

In the prolonged absence of systems in the Bay, the trough migrates to the North, as it did last week when the monsoon went into a weak phase except over the North-East and along the foothills.

IMD said this morning that the trough continues to run close to foothills and may stay as such during the next two days. But the eastern end may shift southwards from tomorrow.

Meanwhile, the North-Eastern states and the hills of Bengal may witness widespread to widespread rainfall with isolated heavy falls until tomorrow. This is due to due to downstream convergence of westerly winds with the southerlies from the Bay.

Subdued rainfall may prevail over the rest of the country during the next three days. But the Western Himalayan region and Punjab are likely to witness enhanced precipitation with the arrival of a western disturbance today and tomorrow.

Western disturbance

Arrival of the disturbance is a clear signal of the weakening of the monsoon, with winds likely turning gradually anti-cyclonic (consolidating dry weather) over the Rajasthan region into next week.

The low-pressure area forming over the Bay would enter North-West India only to be driven towards the South by the northerly winds surrounding the anticyclone.

IMD said that winds over the Andaman Sea, East-Central Bay and South-West Bay would strengthen from Sunday ahead of formation of the 'low' on Tuesday.

In view of the likely adverse sea conditions, fishermen are advised not to venture into these areas on Sunday and Monday. They may plan their trips into the deep seas based on further updates only.

An extended outlook valid from September 19 to 21 said that widespread rain is likely over Andaman and Nicobar Islands while being scattered to fairly widespread over the northern parts of Peninsular India and adjoining Central India.

Isolated rainfall likely over the the rest of the country outside the plains of North-West India where dry weather is likely to prevail.

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