The four-month monsoon season has drawn to a close with above-normal rains over India. The drought-prone areas of West Rajasthan and Saurashtra-Kachchh became the wettest this season with +70% more than usual rains, while the key agricultural state of Punjab saw a shortfall of nearly -28%.
According to India Meteorological Department (IMD) chief Dr M Mohapatra, this was largely due to the 14 low-pressure systems which formed over the Bay of Bengal, most of which travelled along central India, Rajasthan and Gujarat towards the Arabian Sea. Very few of them moved towards the foothills of the Himalayas, hence the deficit in Punjab (-28%) and Jammu and Kashmir (-26%).
These weather systems are responsible for the majority of the rain during the season, and can also intensify to become ‘depressions/deep depressions’. “After a long time, we got so many intensified systems. There were six such depressions, normally we have been getting only 3-4 during the last 20 years. Overall, it was a good monsoon year. Nearly 89% of the sub-divisional area of the country saw normal to above-normal rains. It was below normal in the remaining 11%,” he added.
According to IMD, the seasonal rainfall was 108% of the long-period average (LPA) from June to September. Monsoon between 96-104% of the LPA is considered normal.
The monsoon was powered by 14 low-pressure systems against the normal of 13, but they lasted for nearly 69 days compared to the usual 55. Six of them intensified and one of them turned into a rare cyclonic storm, Asna, which caused disastrous rain spells over Gujarat and adjoining Rajasthan districts.
Region-wise, only northeast India recorded below-normal rains (86% of LPA), while it was ‘above-normal’ over northwest India (107%), central India (119%), and the south peninsula (114% of LPA).
Sub-division-wise, the deficit persisted in Punjab (-28%), Jammu and Kashmir (-26%), and Arunachal Pradesh (-28%). Another major reason for the deficient rain in north India was the southward position of the monsoon trough for most of the season. Also, there were no major western disturbances all through the season, which could have made up for the shortfall in the Himalayan foothills.
MONSOON WITHDRAWAL FROM NORTHWEST INDIA THIS WEEK
The monsoon has already begun its withdrawal from west Rajasthan on September 23. However, its retreat from north-western states has been delayed again this year. Forecasters predict it could take another week to retreat from Punjab, Haryana, Delhi, Himachal Pradesh and parts of Uttarakhand.
But IMD has still indicated a high probability of excess rains in October – which could be 115% of the long-period average (LPA). The rains are likely to be ‘above-normal’ over most parts of the country, except some parts of northeast and northwest India like Punjab.
EXCESS RAINS IN SOUTHERN PENINSULA THIS WINTER
Meanwhile, the southern peninsula is bracing for its ‘winter monsoon’ – the north-east monsoon which normally arrives over the southern coast by October 15. It is responsible for bringing 30% of the annual rainfall over the five subdivisions of Tamil Nadu-Puducherry, Kerala, south interior Karnataka, Rayalaseema, and coastal Andhra Pradesh during October-December.
According to IMD, the region is likely to witness above-normal rains during this period – at least 112% above the long-period average (LPA). “There is a good probability of ‘above-normal’ rains for the entire southeast peninsula this year. However, it may be near-normal in Tamil Nadu as the state usually does not get very good rains during a La-Nina year. However, the exact picture will get clear once the north-east monsoon sets in,” said the IMD chief on Tuesday.
Comments
0 comment