Rare Arabian Sea ‘low’ joins monsoon party, drives up rainfall to new high

Sheer strength of flows across central and west India has torn up the skies over northeast Arabian Sea, Saurashtra, Kutch and west Gujarat for a rare low-pressure area.

This is as rare as it comes not just because of the location but also due to the presence of another ‘low’ within sniffing distance over Madhya Pradesh and east Rajasthan.

RARE ENSEMBLE

No two ‘lows’ can co-exist over land at any point of the four-month season in such close proximity except under the rarest of circumstances.

But today is no ordinary day meteorologically speaking, and represents a new peak in the heavy to very heavy monsoon conditions prevailing here in the last few days.

Collectively, the two ‘lows’ represent one of the most active phases of the monsoon ever recorded over a command area covering Gujarat and adjoining southwest Rajasthan, and that too when the monsoon should normally start withdrawing from these parts.

According to the US Climate Prediction Centre, the existing ‘low’ over Madhya Pradesh will now head north-northwest and interact with an incoming western disturbance to trigger heavy rain over Delhi-Haryana-Punjab region.

NEW-BORN ‘LOW’

The just-born ‘low’ over northeast Arabian Sea will move towards Gujarat and cross into the Bhuj-Jamnagar belt and create a wet corridor to link with the counterpart over Delhi-Punjarb region.

Already, the new ‘low’ has enlivened the offshore trough that runs now from south Gujarat to Lakshadweep. This should take care of the proceedings along the west coast.

This apart, the Bay of Bengal is expected to spin up another low-pressure area within the next two-three days.

An India Met Department update said a preparatory cyclonic circulation would park itself over northwest Bay of Bengal within the next two days.

MJO WAVE

Meanwhile, an Australian Bureau of Meteorology update identified the main driver of the enhanced monsoon as a Madden-Julian Oscillation (MJO) currently positioned over eastern Indian Ocean.

The MJO wave passes periodically from east Africa to the Pacific across the Indian Ocean and can influence ground level weather from high in the atmosphere.

It has been known to set up clouding, create low-pressure areas and storms and even oversee monsoon onsets during its transit across the Indian Ocean.

Last week, it was active over the western part of Indian Ocean and contiguous southeast Arabian Sea, triggering enhanced monsoon activity over peninsular India.

VIGOROUS MONSOON

This week, it has moved further east along its usual track and is parked now over the east, an update from the Australian Bureau of Meteorology said.

As a result, southern India, the Bay of Bengal and South-East Asia have seen an increase in monsoonal activity, it added.

The west Pacific Ocean, on the other hand, is currently under suppressed convective conditions.

There is no hint of a low-pressure area or a developing typhoon that can distract a vigorous run of the monsoon over the Indian subcontinent.

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