Monsoon report card: Sept saving grace, India 2% behind season’s normal

The southwest monsoon, which determines the fate of Indian’s agrarian economy, has ensured a rainfall of 850.3 mm as of Monday, just 2 per cent short of the season’s normal and may see a delayed retreat against its predicted withdrawal from September 17.

While several parts of the country initially received deficient rainfall, the all-India cumulative rainfall only reached normal levels last week with September being the wettest month so far, say reports.

According to India Meteorological Department (IMD), rainfall in the country was below the normal mark between July and September 21. While Northwest India experienced deficient rainfall since July 3, East and Northeast India had a comparatively dry spell since July 7. Central India, which receives the most rainfall, experienced deficient rainfall from July onwards till September 15.

The southwest monsoon arrived in India on June 3, three days late against its expected arrival on June 1.

The IMD while forecasting the arrival of the monsoon in April had predicted it to be “normal” at around 98 per cent of the Long Period Average (LPA). The current LPA of southwest monsoon rainfall, based on the average rainfall between 1961 -2010, is 880.6mm.

The remnants of very severe Cyclone Yaas (which made landfall in Odisha’s Balasore on May 26) paired by the subsequent onset of monsoon in Kerala helped in bringing rains to the Southern peninsula, the east, the northeast and central India in June. The country received an average rainfall of 182.9 mm or roughly 11 per cent more than the normal rainfall in June (166.9 mm).

Also read: Cyclone Gulab may be preparing for second coming; know more here

The next month, however, witnessed a lull of 23 days before the monsoon managed to cover the entire country by July 13, which was five days behind schedule. July recorded a cumulative rainfall of -6.8 per cent.

August, which along with July accounts for around 35 per cent of the southwest monsoon rainfall, witnessed extremely deficient rainfall – 190.5 mm – this year and was dubbed the seventh most rain-deficient August in the last 122 years. The rainfall was 24.1 per cent below normal.

During August, rainfall was limited to the Himalayan foothills while the northwest, central and peninsular India were devoid of normal rainfall. The agricultural belt of Central India received only 60 per cent of the LPA while northwest India received 70 per cent of the LPA. All the districts of Gujarat and the Kutch-Saurashtra region received deficient rainfall.

Weather experts attributed the deficient rains to the failure in development of low pressure systems in the Bay of Bengal, a usual occurrence in the month of August, and due to limited presence of monsoon troughs largely in the foothills of the Himalayas. Low pressure systems that form in the Bay of Bengal during August intensify into depression and bring rains to east Central India. These low-pressure systems originate from typhoons formed in the west Pacific Ocean during July-September, and move west to re-enter the Bay of Bengal. However, this year most of the typhoons recurved and moved towards the north-east direction, D Sivanand Pai, head of Climate Research and Services, IMD, Pune told Indian Express.

However, isolated parts of Uttarakhand, Madhya Pradesh, Odisha and Jharkhand witnessed heavy rains during the month.

September turned out to be the saving grace as four low-pressure systems aided in bringing rains to parched Central and Northwest India.

India recorded 205 mm rainfall – 29.3 per cent surplus – in September alone, while it is expected the monsoon may reach the normal level as rains are forecasted till October 1 due to the remnants of Cyclone Gulab.

While the first deep depression in September brought over 400 mm of rain in Odisha, another low pressure area helped Gujarat receive a total of 515 mm or 61 per cent of the season’s average by September 12. The count increased to 625 mm on September 19 (75 per cent of the season’s average rainfall).

Delhi, which remained dry in July received nearly 70 per cent of its season’s (553.8 mm) rainfall in the first week of September itself. The national capital which recorded 29.6 mm of rainfall in June, followed by a 42 per cent surplus (338.8 mm) in July and 14 per cent deficient rainfall (214.5) in August, received 386.5 mm in September (as of September 13).

The low pressure in the Bay of Bengal which has intensified in the form of Cyclone Gulab, has brought rains to Odisha and Andhra Pradesh, while its remnants are expected to bring heavy rains to Odisha, the Gangetic West Bengal, Jharkhand, north-central Maharashtra and north Konkan, Marathawada and Saurashtra and Kutch in Gujarat.

The monsoon, which was predicted to withdraw from September 17 onwards is now expected to delay its withdrawal and may stay on till October 6, thus making 2021 the year of the second-most delayed retreat of monsoon since 1975.