Southwest monsoon ends with below-normal level rains in the country. As of September 29, nationwide cumulative rainfall deficiency stood at 6% of the long-period average (LPA) of the total rainfall for the season. The country, in the season, had recorded a total of 814.9 mm of rain against the normal average of 865 mm. Kerala reported rainfall deficiency as high as 36%, followed by Jharkhand at 27%, and Bihar 24%.
During the southwest monsoon, east and northeast India recorded 1,108.4 mm rain, between June 1 and September 29, against the normal rainfall of 1,361.2 mm of the said time period. The southern peninsula recorded 650 mm of rain against 710 mm of normal rainfall, central India recorded 974.8 mm against 974.7 mm, and northwest India recorded 593.0 mm against 586.6 mm.
It is to be noted that out of 36 meteorological subdivisions in the country, 26 subdivisions recorded normal rainfall, which covered 73% of the area of the country. Meanwhile, seven subdivisions recorded deficit rainfall that covered 18% of the area. Only three subdivisions witnessed excess rainfall amounting to an area of 7%.
The reason for the deficit was the influence of the El Nino in the Pacific Ocean. Experts have warned that monsoon rains would be less in the second half of the monsoon. Despite the warning, two low-pressure areas saved the country from the drought.
According to the statement by Climate Trends, a research-based initiative, delayed monsoon onset and slow progress in the following weeks resulted in deficit rainfall in June of up to 10%. “Cyclone Biparjoy, which emerged in the Arabian Sea, was responsible for initiating the onset of the monsoon over Kerala. However, as it intensified, it took away all the moisture from the country and stalled the progress as well as the performance of the Monsoon in June, resulting in double-digit deficiency,” the statement noted. The absence of the monsoon rains during that period also resulted in the humid heatwave conditions across east India. Meanwhile, in July, the rain poured across the country except in east and northeast parts of the country.
Prolonged ‘break monsoon’ conditions
The core monsoon month of August accounted for an all-time low cumulative rainfall of the century, on account of prolonged ‘break monsoon’ conditions. It was the third longest break-monsoon period of the century in August 2023, after 2002 and 2009. Gujarat reported rainfall deficiency of 90.67%, followed by Kerala at 86.61%, Rajasthan at 80.15%, Karnataka at 74.16%, and Telangana at 64.66% in August this year.
The initial spell in the month began on August 7 and ended on August 18. The second spell started on August 27 and lasted in early September. As per Climate Trends, the phenomenon of a break in monsoon typically occurs in the months of July and August and lasts for about 1-2 weeks. During these conditions, the monsoon trough, which governs the rainfall over northwest and central India, moves closer to the Himalayas, limiting rainfall over hilly states and adjoining foothills. Monsoon rains revived during the second week of September and the rainfall deficiency recovered from 11% on September 1 to 6% on September 29.
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