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Monsoon late, but macro environment positive

Vinson Kurian THIRUVANANTHAPURAM | Updated on June 26, 2019 Published on June 26, 2019

July, August and September would likely deliver normal to above normal rain for most of the country. File Photo   -  The Hindu

Awaits a ‘low’ nudge from Bay of Bengal

The Indian monsoon may running behind schedule by more than 10 days but the macro environment remains favourable for it to make gains in the short to longer term.

By June end, the monsoon should ideally cover most of the landscape as the Arabian Sea and Bay arms meet over Central India and drive as one into West Rajasthan. But this may not be achieved this time round.

Slow progression

The two arms have just been joined over Madhya Pradesh, but they need a nudge from the Bay to move ahead; this can come about only with the formation of the next low-pressure area in the Bay.

According to the Australian Bureau of Meteorology (BoM), the lack of tropical activity in the Arabian Sea/Bay in recent weeks has contributed to the relatively slow northward progression of the monsoon.

The northern-most extent of the monsoon is currently near central parts of the Indian subcontinent. The average position would typically be nearer to the northernmost third of India at this time of year.

The India Met Department (IMD) expects a ‘low’ to form in another four days, which should help the rains march into the remaining parts of Central India and parts of West and north-West India from July 1 to 3.

The IMD has forecast ‘active’ to ‘vigorous’ monsoon conditions resulting in widespread rainfall with isolated heavy to very heavy and extremely heavy falls over East and North-East India over the next two days.

A weather tracker of the Climate Prediction Centre of the US National Weather Services sees a follow-up ‘low’ forming over the Bay, and triggering a fresh wet spell over North India between July 8 and 12.

El Nino ‘inactive’

If this were to materialise, it should expectedly keep the monsoon busy into the first half of July and also enable it to run over the whole country, bringing to closure the onset phase.

Meanwhile, the Australian Bureau has further downgraded its El Nino 'watch' status to ‘inactive.’ Separately, it reiterated that the positive Indian Ocean Dipole (IOD) phase will run from July to November.

The immediate likelihood of El Nino has passed, meaning, the outlook has been reset to ‘inactive,’ the Bureau explained. El Nino has been harmful for the Indian monsoon, though with exceptions.

While the possibility of El Nino cannot be completely ruled out for 2019, the tropical Pacific Ocean is more likely than not to remain in a ‘neutral’ phase over the coming months.

The Indian Ocean Dipole mimics the El Nino-La Nina phenomena in the Indian Ocean. Its positive phase (the western basin getting warmer than the eastern one) is known to be helpful for the concurrent Indian monsoon.

The Australian Bureau said the Indian Ocean waters remain average to cooler than average in the eastern parts and warmer than average further west, a pattern typical of a positive Indian Ocean Dipole.

While the IOD index had fallen below the positive threshold this week, climate models indicate this is likely to be temporary, with positive values for the Indian Ocean Dipole forecast to persist through the rest of the season.

Published on June 26, 2019
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