Monsoon onset likely to be weak, marginally delayed: IMD

The monsoon season, which begins on June 1, is crucial for summer crops and brings about 70% of India’s annual rainfall. It is especially critical to the country’s agriculture, which is one of the mainstays of its economy. Monsoon spurs farm produce and improves rural spending.

After the initial euphoria over the monsoon moving fast towards the Indian coast and arriving early in Kerala -- it should have arrived already by those projections — meteorologists said it is likely to make a weak, and likely marginally delayed, onset over Kerala following which it will progress slowly during the first week of June.

IMD forecast on May 14 that the monsoon’s onset over Kerala was likely to be on May 27 with a model error of +/-4 days, five days ahead of its expected onset. (PTI)

Conditions are likely to become favourable for onset of monsoon over Kerala during the week between May 26 and June 1, IMD said in its extended range forecast on Thursday. Between June 2 and June 8, overall rainfall activity is likely to be near normal over northeast India; below normal over rest parts of the country, IMD’s forecast said. This indicates monsoon movement may be slow experts said.

The monsoon has advanced into some parts of the Southwest Arabian Sea, some more parts of the Southeast Arabian Sea, Maldives, Comorin and South Bay of Bengal, the India Meteorological Department said on Thursday, with monsoon track map indicating that it is currently a day late than normal.

But the monsoon’s progress had stalled since May 20. It reached Andaman and Nicobar Islands a week ahead of its usual date on May 16 but slowed after that. There is some improvement in progress now and the onset over Kerala is likely early next week but experts said its likely to be a weak onset. This means rainfall will remain light to moderate over Kerala with isolated instances of heavy rain. “Monsoon will progress but we can expect a weak onset over Kerala. The south-westerly winds are not very strong and the normal monsoon surge is not expected. Light to moderate rainfall is likely over Kerala with isolated heavy rain over some regions. Following the onset, its progress will not be very fast and hence we cannot say immediately how and when it will cover central India. This could lead to a marginal setback for early sowing,” said Mahesh Palawat, vice president, climate change and meteorology, Skymet Weather.

The monsoon season, which begins on June 1, is crucial for summer crops and brings about 70% of India’s annual rainfall. It is especially critical to the country’s agriculture, which is one of the mainstays of its economy. Monsoon spurs farm produce and improves rural spending.

Monsoon rains are a lifeline for about 60% of the country’s net cultivated area that has no irrigation. The monsoon impacts inflation, jobs, and industrial demand. Good farm output keeps a lid on food inflation. Ample harvests raise rural incomes and help inject demand into the economy.

There is a 65% rain deficiency over northwest India, 39% deficiency over central India, 76% excess over peninsular India, and 27% excess over east and northeast India in the ongoing pre-monsoon period which started on March 1. Heat wave spells over northwest India during March, April and May reduced wheat crop yield and quality over many regions.

“Monsoon progress is slow but it is raining over Kerala. Monsoon onset can still happen on time but it will not be a very active monsoon onset as was expected earlier. For the next one week, below normal rains are likely over southern peninsula which shows that progress may be weak after onset. The monsoon moves in pulses, it does have weak phases also. Its very difficult to say when it will progress to other states on the west coast,” said DS Pai, director at the Institute of Climate Change Studies, government of Kerala and a former IMD scientist.

“After a period of six days, large-scale atmospheric conditions over the southern Arabian Sea have marginally improved, resulting in the monsoon’s arrival in Sri Lanka on 26 May. Satellite images are showing an improvement in cloud cover over the Maldives-southern Lakshadweep region, where the monsoon will become very active by 31 May. Forecasts continue to suggest that the onset over Kerala could happen sometime between 30 May and 2 June, and it will not be robust this year. Meanwhile, the Bay of Bengal branch of the monsoon has not shown any progress since 20 May, and is not expected to show any significant progress until early June,” said Akshay Deoras, an independent meteorologist and doctoral researcher at the UK’s University of Reading.

“Forecasts from IMD indicate below-normal monsoon rains and a delayed onset for the next two weeks. Not a great sign to look forward to for those regions that have already been hit by a rain deficit and heatwaves during Mar-May,” tweeted Mathew Roxy Koll, climate scientist at Indian Institute of Tropical Meteorology.

IMD has forecast a “normal” monsoon this year at 99% of long period average with margin error of +/-5%. The new LPA for the monsoon season (June to September) is the average for the period between 1971 and 2020 which is 868.6mm.