August, third month of monsoon, ends with 10% excess rain
A region-wise break-up of the data shows rainfall is 21% and 20% excess over central India and southern peninsula, respectively; 9% deficient over the north-west and 2% excess over east and north-east India.
Many parts of Gujarat have reported flooding after Madhya Pradesh (MP) following extremely heavy rainfall was recorded in these areas on Sunday and Monday.
Monsoon rain from June 1 until August 31 is at 10% excess in the country.
A region-wise break-up of the data shows rainfall is 21% and 20% excess over central India and southern peninsula, respectively; 9% deficient over the north-west and 2% excess over east and north-east India.
The India Meteorological Department (IMD) has said rains would gradually reduce over flood-affected regions and start picking up over northern plains, north-eastern states and parts of southern peninsula. There is no likelihood of development of any low-pressure area over the Bay of Bengal, and, as a result, monsoon is likely to be subdued for the coming week, it said.
Parts of Gujarat and Rajasthan are affected by extremely heavy rain, measuring over 20 centimetres (cm), including Jamnagar (24 cm); Jodhpur (23 cm); Dwarka (21 cm); Botad and Morbi (20 cm) each . “But we are not expecting severe floods in Gujarat because it has rained only for a day instead of persistent rains for two-three days such as in MP and Odisha. There is a mid-latitude westerly trough (low-pressure area) that is moving eastwards, while the low-pressure is over western Rajasthan that is moving further west. The convergence of the two is likely to bring heavy rains in Punjab and the adjoining region in Pakistan,” said RK Jenamani, senior scientist at national weather forecasting centre (NWFC), IMD.
“There is no likelihood of any low-pressure area developing over the Bay of Bengal for the next 10 days. So rain will be limited to the northern foothills and southern peninsula, including Kerala and Karnataka, but remain subdued over central India, which is a good thing since the region is impacted by floods. Whenever the monsoon trough moves to the north, a convergence zone develops in the extreme south peninsular region. Hence, heavy rain is likely in Kerala over the next few days,” Jenamani added.
The low-pressure area over western Rajasthan, which brought floods in MP, when it was over western MP, is very likely to move northwards during the next 24 hours and become less marked thereafter. The western end of the monsoon trough lies to the south of its normal position (from Ganganagar in Rajasthan to the Bay of Bengal) and eastern end lies close to the Himalayan foothills.
Due to these favourable conditions widespread to very heavy rainfall is very likely over western Rajasthan on Tuesday. Under the influence of interaction between south-westerly winds from the Arabian Sea and mid-level westerly trough, widespread and heavy rain is also likely over northwest India and western Himalayan region on Wednesday and Thursday. “Under the influence of strengthening of the north-south trough along the east coast, rainfall intensity over peninsular India is very likely to increase from Tuesday. South Interior Karnataka, Kerala and Tamil Nadu are very likely to receive heavy to very heavy rain on Wednesday and Thursday, the IMD bulletin said.
Persistently very heavy to extremely heavy rainfall, measuring over 20 cm, was recorded in two-three days—from August 25 to 27 in Odisha and from August 27 to 30 over MP.
In MP’s Chhindwara district’s 12 weather stations recorded 20 to 41 cm of rain on August 28 to 29. While Chaurai in MP recorded 41 cm in a day, which is likely to be the highest ever recorded figure that the IMD is trying to ascertain. This spell triggered widespread flooding in MP.
Eight dams in Odisha, Maharashtra, MP and Karnataka continue to be at over 100% storage capacity, according to the Central Water Commission (CWC).
August received record rains at 26.3% excess, which is the highest in 44 years. The country has recorded 61.5% and 36.7% excess rainfall over central India and the southern peninsula, respectively; 19.1% deficient over east and the north-east; and 1.9% excess over north-west India.
A good monsoon, which accounts for 70% of India’s annual rainfall, is critical to the fortunes of the agricultural sector on which at least 700 million people are dependent for a livelihood. The monsoon is crucial for the yield of rice, wheat, sugarcane, and oilseeds in a country, where farming accounts for about 15% of the economy but employs over half of its people.
The impact of good monsoon rain on farmers has not been that significant, said experts.
“During the initial days of the coronavirus disease (Covid-19) outbreak, sowing was impacted due to labour shortage and market uncertainty. Now, vegetable growers are affected by severe rains that have damaged the crop in many parts of the country. Consequently, vegetable prices are likely to go up. How efficiently we have used rain water depends on how much harvesting has occurred locally. India doesn’t have large scale systems in place to harvest rainwater locally and run-off is rampant. Rainy days have reduced and extreme rainfall has increased that needs to be factored into a data analysis,” said Ramanjaneyulu GV, executive director, Centre for Sustainable Agriculture, Telangana.
Monsoon is likely to start retreating from September 17, as per the new normal onset and withdrawal dates issued by IMD in April, as compared to September 1 until last year.
IMD’s new onset dates are based on analysis of monsoon data from 1961 to 2019 and withdrawal dates are based from 1971 to 2019 by its scientists in Pune.
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