It is estimated that 82.5 mm of rainfall fell over the country within the first fortnight of October, an amount 88 per cent greater than the Long Period Average (LPA). A total of 76 mm of rainfall was recorded during the month, which was above the climatological normal of 76 mm.
According to the India Meteorological Department (IMD), the country received 82.5 mm of rainfall between October 1-14, of which 58.5 mm occurred between October 6-12.
By the middle of October, the southwest monsoon normally withdraws from most parts of central and northwest India, giving way to a period of drought.
Rainfall trends over the past few years, including 2022, indicate that the monsoon has been ‘delayed’, so rainfall activity continues in the north and central regions until the third week in October.
As a result of this delayed departure, the onset of the Northeast monsoon over southern parts of the country is also delayed past the normal date of October 21.
Only 25 per cent of October months have reported rainfall of more than 80 millimeters throughout India since 1901. According to IMD data, the country experienced its wettest Octobers in 1975 (121.7 mm of rainfall) and 1961 (121.3 mm).
IMD’s data indicates that rainfall in the northwest India region of over 58.4 mm (346 percent excess) during the fortnight of this month is very rare.
From 1901 to 2022 (until October 14), northwest India recorded rainfall exceeding 50 mm in October only 13 times, including twice in this century (2004 and 2022).
Between October 7 and 11, the latest long rains were associated with a cyclonic circulation in lower atmospheric levels, which emerged over north Madhya Maharashtra on October 7 and then moved over south Gujarat, northeast Rajasthan, south Haryana and Punjab.
Over Rajasthan, Delhi, Haryana, Uttar Pradesh and Uttarakhand, this system attracted moist winds from the Bay of Bengal, which interacted with the passing western disturbances, resulting in one of the wettest spells of October in recent memory.
According to IMD’s weekly weather analysis, the interaction caused such a long spell over northwest India, including Delhi-NCR.
|Many parts of India are likely to have cooler weather: IMD|