The monsoon has gone missing from all of north and north-west India in September , and the heat and humidity the region is witnessing may last for the rest of the season, with experts blaming the monsoon trough from Bay of Bengal travelling in a westerly direction instead of the usual north-westerly one for this.
The sultry conditions may last for the next 10-13 days, the experts added, at least till the monsoon fully withdraws from the region without any rainfall.
The withdrawal will finally result in pleasant weather, they added.
According to the India Meteorological Department, the rainfall deficit in the northern part of India in September is near total — up to 99% of the normal, the highest for any region in the country.
The southern states of Karnataka, Andhra Pradesh and Telangana received up to 50% excess rain during the same period with Chitradurga district in Karnataka seeing 245% excess rainfall.
In Himachal, the tribal district of Kinnaur, known for its delicious royal apples harvested this month, received 88% less rainfall, the highest for any district in the state. In Uttar Pradesh, the western parts were almost dry with districts such Bulandshahr and Mathura recording 100% rain deficiency.
Delhi was slightly better than its neighbouring states with 61% rain deficiency. New Delhi, the seat of the Central government, recorded 76% less rainfall than normal, the most for any district in the national capital. Likewise, southern Haryana districts such as Gurugram and Faridabad recorded close to 90% less rainfall.
“Only one trough formed in the Bay of Bengal during this period and that also travelled towards the westerly direction bringing in some rain in West Bengal, Odisha and North-East India. Hence, the north and north-west remained dry,” said Mahesh Palawat, vice president, climate and meteorology, Skymet Weather, a private forecaster.
North and north-west India receive rains due to the oscillation of troughs, getting its moisture feed from the Bay of Bengal and the Arabian Sea. With few troughs forming, the region witnessed westerly winds adding to the humid conditions, said an IMD scientist, who asked not to be named as he is not authorised to speak to media.
The warmer-than-usual period, with temperatures ranging from 32 degrees Celsius in the hills of Himachal and Uttarakhand to 39 degrees in Delhi, five to eight degrees above normal, showed its impact on horticulture crops.
“Because of the excessive heat, the colour of apples in my orchards turned almost yellow from red. No rain has resulted in leaf-fall turning the fruit, which looked good a month ago, into bad quality. Nobody buys a small size and pale red apple,” said Chander Mohan Justa, an orchad owner in Shimla.
Devendra Sharma, an agriculture expert, said poor rainfall in the food bowl states of Punjab, Haryana and Uttar Pradesh, could have some impact in the kharif output. “Though the sowing was good because of good early monsoon rains, the dry patch in August and September has hurt farmers.”
North and north-west India’s loss was east and south India’s gain — depressions in the Arabian Sea and the Bay of Bengal moved towards the west bringing heavy rains.
The western coast, from Maharashtra to Kerala received 90-100% excess rain whereas most of the North-Eastern states received up to 50% more rainfall than normal, IMD data showed.
A recent study by the Indian Institute of Technology, Kharagpur, said that by the end of this century southern India is likely to register the maximum increase in rainfall compared to the states in central and north India. “In the worst-case scenario, rainfall could increase by 2.7 mm per day in north India and by 18.5 mm per day in Western Ghats in southern India,” said Rajib Maity, a professor of civil engineering at IIT Kharagpur, who led the study.
In its weekly forecast, IMD did not project any major rainfall in the remaining part of the monsoon season; the monsoon is expected to withdraw from western India in the third week of September. The temperature is expected to be higher than normal for northern and central Indian plains.
The anti-cyclone activity, a sign of monsoon withdrawal from western India, is now visible in central Pakistan, meaning that the monsoon will start withdrawing from Rajasthan in a week, Palawat said.
Despite less rainfall in September, Mritunjay Mohapatra, director-general of IMD, said on September 8 that je expected the overall monsoon in India to be 102% of the normal with south, central and western India receiving substantially more than normal rainfall .
“We are not expecting any improvement in rain deficiency over northwest India now because we are heading towards monsoon withdrawal,” said DS Pai, senior scientist, IMD Pune, agreeing that the monsoon is pretty much over in northern India.