Agri Business

Monsoon may splutter to life in phases: IMD

Vinson Kurian Thiruvananthapuram | Updated on June 16, 2021

33 per cent surplus rain since June 1

The progress of the monsoon over parts of North-West India remains stalled but India Meteorological Department (IMD) assesses that the jinx will be broken gradually over the next five days as seasonal rains enter more parts of Uttar Pradesh backed by the remnant of an erstwhile low-pressure area.

As of Wednesday, India as a whole has recorded a rainfall surplus of 33 per cent with rainfall deficits being confined to parts of North-East India; Jammu & Kashmir and Ladakh in North-West India; Gujarat in West India; and Puducherry over the South Peninsula and the Lakshadweep Islands.

Rains to sustain

The ‘low’ originated from the Bay of Bengal has weakened into a cyclonic circulation over East Uttar Pradesh on Wednesday. It will still be capable of triggering fairly widespread to widespread rain with thunderstorms and lightning over most parts of East, Central and North-East India during next 4-5 days.

Dry north-westerlies associated with an incoming western disturbance with a depth extending to the North-East Arabian Sea South of Veraval in Gujarat has been blocking the monsoon easterlies that had raced in at least two weeks ahead of normal time but had stopped just short of Delhi a few days ago.

GP Sharma, President, Meteorology and Climate Change at private forecaster Skymet Weather, told BusinessLine the Arabian Sea and the Bay of Bengal branches of the monsoon should meet over North-West India to set up a crucial land-based trough and generate seasonal rain over the region.

Intruding dry north-westerlies intruding do not allow this to happen and this is why the monsoon is currently stalled over the North-West.

Either the prevailing cyclonic circulation over East Uttar Pradesh needs to rev up or a fresh low-pressure area has to form in the Bay to push in the monsoon easterlies.

Strong easterlies blowing across Odisha, Jharkhand and Uttar Pradesh will be able to drive away the intruding north-westerlies and set up a date with the south-westerly winds from the Arabian Sea branch of the monsoon. Sharma expects the monsoon to delay its onset further over the national capital.

Monsoon trough awaited

Absence of easterly winds has thrown up stray cyclonic circulations over Punjab and adjoining North-West Rajasthan and Haryana, South Assam, and over the plains of West Bengal and adjoining Bangladesh.

An overarching diagonal trough links South Punjab and North-West Bengal. This is a proxy for the monsoon trough that comes to life when active monsoon conditions are generated or vice versa and runs down from West Rajasthan to the Bay of Bengal. Isolated very heavy falls are forecast over Bihar on Thursday and over West Bengal and Sikkim until Friday. Scattered to fairly widespread rain, isolated thunderstorms and lightning may erupt over North-West India and relent from Saturday except East Uttar Pradesh where it will continue to rain.

Offshore stays truncated

The truncated offshore trough, the other rainmaker, runs along the Karnataka-Kerala coasts and will sustain fairly widespread to widespread rainfall with isolated heavy rainfall, thunderstorm and lightning over Konkan, Goa, Karnataka and Kerala and Mahe during the next three days.

Isolated very heavy rain is likely over Konkan and Goa (including Mumbai) until Friday and over Coastal Karnataka on Thursday. A pulse of rain-aiding Madden-Julian Oscillation (MJO) wave is currently entering the West Indian Ocean but is too weak to make an impression on the ongoing monsoon.

Published on June 16, 2021

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