New Delhi: Rainfall in August, which recorded 24% deficit, was lowest since 2002, the India Meteorological Department (IMD) said on Friday.
Two major spells of weak monsoon prevailed over the country -- from August 9-16 and August 23-27 -- when northwest, central and adjoining peninsular and west coast of India had subdued rainfall activities.
"During August 2021, rainfall over the country as a whole was below Long Period Average (LPA) by minus 24%. It is also lowest August rainfall in last 19 years, since 2002," the IMD said.
The Southwest Monsoon season officially commences from June 1 and lasts till September 30. However this year, both July and August rainfall were below normal. Between June 1 and August 31, the all-India rainfall was 91% of the Long Period Average (LPA), which is 880 mm.
During the entire month, the country recorded only 190.5 mm of rain. July and August are crucial rainfall months during the four-month-long monsoon season as each accounts for nearly 35% of the season’s rainfall.
The country received 24% less than normal rainfall in August. Of the four meteorological divisions of the IMD, the central India division received 39% less. The division consists of a large swathe of area from Maharashtra, Gujarat, Goa, Madhya Pradesh, Chhattisgarh and Odisha.
The deficiency in the northwest India division, which comprises northern Indian states, was 30%.
The deficiency was 10% in the south peninsula whereas the east and northeast division received two percent more rainfall than the normal.
The IMD had predicted that the rainfall activity was expected to be normal during August. It has now predicted above normal precipitation in September.
The weather forecasting agency said intra-seasonal variation in terms of week by week rainfall variation over India shows that monsoon rainfall activities were largely subdued consecutively for three weeks -- for week ending on August 11, August 18 and August 25 -- when all India weekly cumulative rainfall for the country as a whole was 35%, 36% and 21%, respectively, below its Long Period Average (LPA).
The formation of less number of low pressure systems (PLS) and their lesser number of days compared to the climatology and absence of their longer westward movements during the month of August 2021 contributed to the large deficient rainfall in central India as well as all India, the IMD said.
It said negative Indian Ocean Dipole (IOD) over tropical Indian Ocean, unfavourable for Indian monsoon prevailed throughout the month of the August, which also contributed to deficient rainfall over India in the month.
A negative IOD is associated with the heating of waters of the Indian Ocean.
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